AP bio getting wrecked Flashcards

About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
A) carbon, sodium, hydrogen, nitrogen
B) carbon, oxygen, phosphorus, hydrogen
C) oxygen, hydrogen, calcium, nitrogen
D) carbon, hydrogen, nitrogen, oxygen
E) carbon, oxygen, nitrogen, calcium

Answer: D

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?
A) nitrogen
B) calcium
C) iodine
D) sodium
E) phosphorus

Answer: C

Which of the following statements is false?
A) Carbon, hydrogen, oxygen, and nitrogen are the most abundant elements of living matter.
B) Some trace elements are very abundant on Earth.
C) Virtually all organisms require the same elements in the same quantities.
D) Iron is an example of an element needed by all organisms.
E) Other than some trace elements, animals are mostly made up of the same elements as plants, in similar proportions.

Answer: C

What factors are most important in determining which elements are most common in living matter?
A) the relative abundances of the elements in Earth's crust and atmosphere
B) the emergent properties of the simple compounds made from these elements
C) the reactivity of the elements with water
D) the chemical stability of the elements
E) both the relative abundances of the elements and the emergent properties of the compounds made from these elements

Answer: E

Why is each element unique and different from other elements in chemical properties?
A) Each element has a unique atomic mass.
B) Each element has a unique atomic weight.
C) Each element has a unique number of protons in its nucleus.
D) Each element has a unique number of neutrons in its nucleus.
E) Each element has different radioactive properties.

Answer: C

Knowing just the atomic mass of an element allows inferences about which of the following?
A) the chemical properties of the element
B) the number of protons in the element
C) the number of neutrons in the element
D) the number of protons plus neutrons in the element
E) both the number of protons and the chemical properties of the element

Answer: D

In what way are elements in the same column of the periodic table the same?
A) They have the same number of protons.
B) They have the same number of neutrons.
C) They have the same number of electrons.
D) They have the same number of electrons in their valence shell.
E) They have the same number of electron shells.

Answer: D

Oxygen has an atomic number of 8 and a mass number of 16. Thus, what is the atomic mass of an oxygen atom?
A) exactly 8 grams
B) exactly 8 daltons
C) approximately 16 grams
D) approximately 16 daltons
E) 24 amu (atomic mass units)

Answer: D

) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
A) The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14.
B) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7.
C) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams.
D) The nitrogen atom has a mass number of 7 and an atomic number of 14.
E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons.

Answer: E

Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers of 92, 94, 95, 96, 97, 98, and 100. Therefore, which of the following can be true?
A) Molybdenum atoms can have between 50 and 58 neutrons.
B) The isotopes of molybdenum have different electron configurations.
C) The isotopes of molybdenum can have between 50 and 58 protons.
D) The isotopes of molybdenum have between 50 and 58 neutrons and have different electron configurations.
E) The isotopes of molybdenum have between 50 and 58 protons and have different electron configurations.

Answer: A

Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why?
A) The atomic mass does not include the mass of electrons.
B) Some carbon atoms in nature have an extra proton.
C) Some carbon atoms in nature have more neutrons.
D) Some carbon atoms in nature have a different valence electron distribution.
E) Some carbon atoms in nature have undergone radioactive decay.

Answer: C

Which of the following best describes the relationship between the atoms described below? [SEE IMAGE]
A) They are isomers.
B) They are polymers.
C) They are isotopes.
D) They contain 1 and 3 protons, respectively.
E) They each contain 1 neutron.

Answer: C

The precise weight of a mole of some pure elements like silicon (Si) can vary slightly from the standard atomic mass, or even from sample to sample. Why?
A) The element may undergo radioactive decay.
B) The element may react with itself and gain or lose subatomic particles.
C) The atoms of the element form chemical bonds with each other, and that changes the weight of the element.
D) The element may have multiple stable isotopes, and the isotopic composition may vary from sample to sample.
E) The amount of energy absorbed by the element affects the mass of its electrons, and thus the atomic mass can vary slightly.

Answer: D

One difference between carbon-12 (12/6 C) is that carbon-14 (14/6 C) has
A) two more protons than carbon-12.
B) two more electrons than carbon-12.
C) two more neutrons than carbon-12.
D) two more protons and two more neutrons than carbon-12.
E) two more electrons and two more neutrons than carbon-12.

Answer: C

An atom has 6 electrons in its outer shell. How many unpaired electrons does it have?
A) 0
B) 2
C) 4
D) 6
E) 2 or 4

Answer: B

The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?
A) 6
B) 7
C) 8
D) 12
E) 14

Answer: C

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
A) an electron may move to an electron shell farther away from the nucleus.
B) an electron may move to an electron shell closer to the nucleus.
C) the atom may become a radioactive isotope.
D) the atom would become a positively charged ion, or cation, and become a radioactive isotope.
E) the atom would become a negatively charged ion, or anion.

Answer: A

The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?
A) It has 8 electrons in its outer electron shell.
B) It is inert.
C) It has an atomic mass of 10 daltons.
D) It has 8 electrons in its outer electron shell and it is inert.
E) It has 8 electrons in its outer electron shell, it is inert, and it has an atomic mass of 10 daltons.

Answer: D

From its atomic number of 15, it is possible to predict that the phosphorus atom has
A) 15 neutrons.
B) 15 protons.
C) 15 electrons.
D) 8 electrons in its outermost electron shell.
E) 15 protons and 15 electrons.

Answer: E

Atoms whose outer electron shells contain 8 electrons tend to
A) form ions in aqueous solutions.
B) form hydrogen bonds in aqueous solutions.
C) be stable and chemically nonreactive, or inert.
D) be gaseous at room temperature.
E) be both chemically inert and gaseous at room temperature.

Answer: E

1-20 Section 2

The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (12/6 C)?
A) ₇N nitrogen
B) ₉F flourine
C) ₁₀Ne neon
D) ₁₂Mg magnesium
E) ₁₄Si silicon

Answer: E

Two atoms appear to have the same mass number. These atoms
A) must have the same atomic number.
B) must have the same number of electrons.
C) must have the same chemical properties.
D) must have the same number of protons + neutrons.
E) must have the same atomic number, the same number of protons + neutrons, the same number of electrons, and the same chemical properties.

Answer: D

Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom?
A) 1
B) 3
C) 0
D) 7
E) 9

Answer: A

24) What is the maximum number of electrons in a single 2 p orbital of an atom?
A) 1
B) 2
C) 3
D) 4
E) 5

Answer: B

The organic molecules in living organisms have a measurably lower ratio of carbon-13/carbon-12, two stable isotopes of carbon that comprise approximately 1.1% and 98.9% of atmospheric carbon, respectively. What is a reasonable explanation for this phenomenon?
A) Photosynthesis preferentially uses carbon dioxide molecules with carbon-12, and the lower carbon-13/carbon-12 ratio propagates through the food chain.
B) Carbon dioxide molecules with carbon-13 stay in the upper atmosphere and are less available to terrestrial plants and algae.
C) Carbon-13 has a different valence electron configuration and is therefore less chemically reactive than carbon-12.
D) Oxygen atoms preferentially react with carbon-13, thereby enriching the atmosphere with carbon dioxide molecules containing carbon-13 atoms.
E) Carbon dioxide molecules containing carbon-13 are heavier and sink into the ocean depths, making them less available to living organisms.

Answer: A

Phosphorus-32, a radioactive isotope of phosphorus-31 (atomic number 15), undergoes a form of radioactive decay whereby a neutron turns into a proton and emits radiation in the form of an electron. What is the product of such radioactive decay of phosphorus-32?
A) phosphorus-31
B) a positively charged phosphorus-31 ion
C) a negatively charged phosphorus-32 ion
D) sulfur-32 (atomic number 16)
E) the conversion of the phosphorus-32 atom into pure energy

Answer: D

An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
A) It would form ions with a +1 charge.
B) It would form ions with a +2 charge.
C) It would form ions with a -1 charge.
D) It would form ions with a -2 charge.
E) It would form two covalent bonds with other atoms.

Answer: B

If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for this animal?
A) a surface coated with a thin film of water
B) a surface made with carbon and hydrogen atoms covalently bonded together
C) a surface made with carbon, hydrogen, and oxygen atoms covalently bonded together
D) a surface made with carbon, hydrogen, nitrogen, and oxygen atoms covalently bonded together
E) a surface made with silicon and oxygen atoms covalently bonded together

Answer: B

A covalent chemical bond is one in which
A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged.
B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms.
C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms.
D) outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom.
E) an electron occupies a hybrid orbital located between the nuclei of two atoms.

Answer: C

If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed?

[SEE IMAGE FOR CHOICES]

Answer: B

What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?
A) 1
B) 2
C) 3
D) 4
E) 6

Answer: B

Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH₃)?
A) Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
B) The nitrogen atom has a strong positive charge; each hydrogen atom has a strong positive charge.
C) Each hydrogen atom has a slight negative charge; the nitrogen atom has a strong positive charge.
D) The nitrogen atom has a slight positive charge; each hydrogen atom has a slight negative charge.
E) There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom.

Answer: A

When two atoms are equally electronegative, they will interact to form
A) hydrogen bonds.
B) van der Waals interactions.
C) polar covalent bonds.
D) nonpolar covalent bonds.
E) ionic bonds.

Answer: D

What results from an unequal sharing of electrons between atoms?
A) a nonpolar covalent bond
B) a polar covalent bond
C) an ionic bond
D) a hydrogen bond
E) a hydrophobic interaction

Answer: B

A covalent bond is likely to be polar when
A) one of the atoms sharing electrons is much more electronegative than the other atom.
B) the two atoms sharing electrons are equally electronegative.
C) oxygen is one of the two atoms sharing electrons.
D) one of the atoms has absorbed more energy than the other atom.
E) the two atoms sharing electrons are different elements.

Answer: A

Which of the following molecules contains the most polar covalent bond?
A) H₂
B) O₂
C) CO₂
D) H₂O
E) CH₄

Answer: D

In comparing covalent bonds and ionic bonds, which of the following would you expect?
A) An atom can form covalent bonds with multiple partner atoms, but only a single ionic bond with a single partner atom.
B) Covalent bonds and ionic bonds occupy opposite ends of a continuous spectrum, from nearly equal to completely unequal sharing of electrons.
C) Both involve electrical attraction between the electrons of one atom and the nucleus of the other atom.
D) Ionic interactions remain when covalent bonds are broken in water. Ionic bonds are much stronger than covalent bonds.

Answer: B

What is the difference between covalent bonds and ionic bonds?
A) Covalent bonds are formed between atoms to form molecules; ionic bonds are formed between atoms to form compounds.
B) Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms.
C) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
D) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms.
E) Covalent bonds involve the transfer of electrons between atoms; ionic bonds involve the sharing of electrons between atoms.

Answer: C

In ammonium chloride salt (NH₄Cl) the anion is a single chloride ion, Cl. What is the cation of NH₄Cl?
A) N, with a charge of +1
B) NH, with a charge of +1
C) H₃, with a charge of +1
D) NH₄, with a charge of +1
E) NH₄, with a charge of +4

Answer: D

The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?
A) MgCl
B) MgCl₂
C) Mg₂Cl
D) Mg₂Cl₂
E) MgCl₃

Answer: B

21-40 Section 2

How many electron pairs are shared between carbon atoms in a molecule that has the formula C₂H₄?
A) 0
B) 1
C) 2
D) 3
E) 4

Answer: C

Which bond or interaction would be difficult to disrupt when compounds are put into water?
A) covalent bond
B) hydrogen bond
C) van der Waals interaction
D) ionic bond
E) either covalent bonds or ionic bonds

Answer: A

Which of the following explains most specifically the attraction of water molecules to one another?
A) nonpolar covalent bond
B) polar covalent bond
C) ionic bond
D) hydrogen bond
E) hydrophobic interaction

Answer: D

Van der Waals interactions result when
A) hybrid orbitals overlap.
B) electrons are not symmetrically distributed in a molecule.
C) molecules held by ionic bonds react with water.
D) two polar covalent bonds react.
E) a hydrogen atom loses an electron.

Answer: B

What bonding or interaction is most likely to occur among a broad array of molecules of various types (polar, nonpolar, hydrophilic, hydrophobic)?
A) covalent bonding
B) polar covalent bonding
C) ionic bonding
D) hydrogen bonding
E) van der Waals interactions

Answer: E

Which of the following is not considered to be a weak molecular interaction?
A) a covalent bond
B) a van der Waals interaction
C) an ionic bond in the presence of water
D) a hydrogen bond
E) both a hydrogen bond and a covalent bond

Answer: A

Which of the following would be regarded as compounds?
A) H₂O, O₂, and CH₄
B) H₂O and O₂
C) O₂ and CH₄
D) CH₄ and O₂, but not H₂O
E) H₂O and CH₄, but not O₂

Answer: E

What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms?
A) 2
B) 3
C) 4
D) 6
E) 8

Answer: D

of the following is true for this reaction?
3 H₂ + N₂ ↔ 2 NH₃
A) The reaction is nonreversible.
B) Hydrogen and nitrogen are the reactants of the reverse reaction.
C) Hydrogen and nitrogen are the products of the forward reaction.
D) Ammonia is being formed and decomposed.
E) Hydrogen and nitrogen are being decomposed.

Answer: D

Which of the following correctly describes chemical equilibrium?
A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products.
B) Concentrations of products are higher than the concentrations of the reactants.
C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products.
D) Reactions stop only when all reactants have been converted to products.
E) There are equal concentrations of reactants and products, and the reactions have stopped.

Answer: A

Which of the following correctly describes any reaction that has reached chemical equilibrium?
A) The concentration of the reactants equals the concentration of the products.
B) The rate of the forward reaction is equal to the rate of the reverse reaction.
C) All of the reactants have been converted to the products of the reaction.
D) All of the products have been converted to the reactants of the reaction.
E) Both the forward and the reverse reactions have stopped with no net effect on the concentration of the reactants and the products.

Answer: B

Which of these systems is least likely to be at chemical equilibrium?
A) a test tube of living cells
B) a test tube of organic molecules, kept in the freezer
C) a test tube of dry organic molecules, kept at room temperature
D) a test tube of organic molecules dissolved in water, kept at room temperature
E) a test tube of dead cells in water, kept at room temperature

Answer: A

Refer to the figure above (first three rows of the periodic table). If life arose on a planet where carbon is absent, which element might fill the role of carbon?
A) boron
B) silicon
C) nitrogen
D) aluminum
E) phosphorus

Answer: B

Which drawing in the figure above depicts the electron configuration of an element with chemical properties most similar to Helium (₂He)?
A) A
B) B
C) C
D) D
E) E

Answer: E

Which drawing in the figure above depicts the electron configuration of an atom that can form covalent bonds with two hydrogen atoms?
A) A
B) B
C) C
D) D
E) E

Answer: C

Which drawing in the figure above depicts the electron configuration of an atom capable of forming three covalent bonds with other atoms?
A) A
B) B
C) C
D) D
E) E

Answer: B

Which drawing in the figure above is of the electron configuration of a sodium ₁₁Na⁺ ion?
A) A
B) B
C) C
D) D
E) E

Answer: E

Which drawing in the figure above depicts the most electronegative atom?
A) A
B) B
C) C
D) D
E) E

Answer: D

Which drawing in the figure above depicts an atom with a valence of 3?
A) A
B) B
C) C
D) D
E) E

Answer: B

Which drawing in the figure above depicts an atom with a valence of 2?
A) A
B) B
C) C
D) D
E) E

section 2 41-60

In the figure above, how many electrons does nitrogen have in its valence shell?
A) 2
B) 5
C) 7
D) 8
E) 14

Answer: B

In the figure above, how many unpaired electrons does phosphorus have in its valence shell?
A) 15
B) 2
C) 3
D) 7
E) 5

Answer: C

How many neutrons are present in the nucleus of a phosphorus-32 (³²P) atom (see the figure above)?
A) 5
B) 15
C) 16
D) 17
E) 32

Answer: D

How many electrons does an atom of sulfur have in its valence shell (see the figure above)?
A) 4
B) 6
C) 8
D) 16
E) 32

Answer: B

Based on electron configuration, which of these elements in the figure above would exhibit a chemical behavior most like that of oxygen?
A) carbon
B) hydrogen
C) nitrogen
D) sulfur
E) phosphorus

Answer: D

The illustration above shows a representation of formic acid. A formic acid molecule
A) will form hydrogen bonds with water molecules.
B) has a tetrahedral configuration of hybrid electron orbitals for the carbon atom.
C) consists of largely nonpolar covalent bonds.
D) is held together by hydrogen bonds.
E) has a tetrahedral shape and will form hydrogen bonds with water molecules.

Answer: A

What results from the chemical reaction illustrated above?
A) a cation with a net charge of +1
B) a cation with a net charge of -1
C) an anion with a net charge of +1
D) an anion with a net charge of -1
E) a cation with a net charge of +1 and an anion with a net charge of -1

Answer: E

What is the atomic number of the cation formed in the reaction illustrated above?
A) 1
B) 8
C) 10
D) 11
E) 16

Answer: D

What causes the shape of the molecule shown above?
A) the configuration of the 2 p orbitals in the carbon atom
B) the configuration of the 1 s orbital in the carbon atom
C) the configuration of the sp hybrid orbitals of the electrons shared between the carbon and hydrogen atoms
D) the packing of the carbon and hydrogen atoms in a crystal lattice
E) hydrogen bonding configurations between the carbon and hydrogen atoms

Answer: C

In the methane molecule shown in the figure above, bonds have formed that include both the s orbital valence electrons of the hydrogen atoms and the p orbital valence electrons of the carbon. The electron orbitals in these bonds are said to be
A) double orbitals.
B) tetrahedral orbitals.
C) complex orbitals.
D) hybrid orbitals.
E) polar orbitals.

Answer: D

Which one of the atoms shown would be most likely to form a cation with a charge of +1?

[SEE IMAGE FOR CHOICES]

Answer: A

Which one of the atoms shown would be most likely to form an anion with a charge of -1?

[SEE IMAGE FOR CHOICES]

Answer: D

Which of the following pairs of atoms would be most likely to form a polar covalent bond?

[SEE IMAGE FOR CHOICES]

Answer: A

Which of the following pairs of atoms would be most likely to form an ionic bond?

[SEE IMAGE FOR CHOICES]

Answer: B

group of molecular biologists is trying to synthesize a new artificial compound to mimic the effects of a known hormone that influences sexual behavior. They have turned to you for advice. Which of the following compounds is most likely to mimic the effects of the hormone?
A) a compound with the same number of carbon atoms as the hormone
B) a compound with the same molecular mass (measured in daltons) as the hormone
C) a compound with the same three-dimensional shape as part of the hormone
D) a compound with the same number of orbital electrons as the hormone
E) a compound with the same number of hydrogen and nitrogen atoms as the hormone

Answer: C

In the term trace element, the modifier trace means that
A) the element is required in very small amounts.
B) the element can be used as a label to trace atoms through an organism's metabolism.
C) the element is very rare on Earth.
D) the element enhances health but is not essential for the organism's long-term survival.
E) the element passes rapidly through the organism.

Answer: A

Compared with ³¹P, the radioactive isotope ³²P has
A) a different atomic number.
B) a different charge.
C) one more proton.
D) one more electron.
E) one more neutron.

Answer: E

The reactivity of an atom arises from
A) the average distance of the outermost electron shell from the nucleus.
B) the existence of unpaired electrons in the valence shell.
C) the sum of the potential energies of all the electron shells.
D) the potential energy of the valence shell.
E) the energy difference between the s and p orbitals.

Answer: B

Which statement is true of all atoms that are anions?
A) The atom has more electrons than protons.
B) The atom has more protons than electrons.
C) The atom has fewer protons than does a neutral atom of the same element.
D) The atom has more neutrons than protons.
E) The net charge is 1-.

Answer: A

Which of the following statements correctly describes any chemical reaction that has reached equilibrium?
A) The concentrations of products and reactants are equal.
B) The reaction is now irreversible.
C) Both forward and reverse reactions have halted.
D) The rates of the forward and reverse reactions are equal.
E) No reactants remain. Anwer: D

Section 2 61-80

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
A) hydrogen bonds.
B) nonpolar covalent bonds.
C) polar covalent bonds.
D) ionic bonds.
E) van der Waals interactions.

Answer: C

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
A) a covalent bond
B) a hydrogen bond
C) an ionic bond
D) a hydrophilic bond
E) a van der Waals interaction

Answer: B

The partial negative charge in a molecule of water occurs because
A) the oxygen atom acquires an additional electron.
B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.
C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms.
D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus.
E) one of the hydrogen atoms donates an electron to the oxygen atom.

Answer: B

Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H₂S
A) will ionize more readily.
B) will have greater cohesion to other molecules of H₂S.
C) will have a greater tendency to form hydrogen bonds with each other.
D) will have a higher capacity to absorb heat for the same change in temperature.
E) will not form hydrogen bonds with each other.

Answer: E

Water molecules are able to form hydrogen bonds with
A) compounds that have polar covalent bonds.
B) oils.
C) oxygen gas (O₂) molecules.
D) chloride ions.
E) any compound that is not soluble in water.

Answer: A

Which of the following effects is produced by the high surface tension of water?
A) Lakes don't freeze solid in winter, despite low temperatures.
B) A water strider can walk across the surface of a small pond.
C) Organisms resist temperature changes, although they give off heat due to chemical reactions.
D) Evaporation of sweat from the skin helps to keep people from overheating.
E) Water flows upward from the roots to the leaves in plants.

Answer: B

Which of the following takes place as an ice cube cools a drink?
A) Molecular collisions in the drink increase.
B) Kinetic energy in the drink decreases.
C) A calorie of heat energy is transferred from the ice to the water of the drink.
D) The specific heat of the water in the drink decreases.
E) Evaporation of the water in the drink increases.

Answer: B

A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1 kilocalorie?
A) 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1,000°C
B) 100 calories, or the amount of heat required to raise the temperature of 100 g of water by 1°C
C) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F
D) 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C
E) 1,000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C

Answer: D

The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius?
A) 0.2°C
B) 1.0°C
C) 2.0°C
D) 10.0°C
E) 20.0°C

Answer: D

Liquid water's high specific heat is mainly a consequence of the
A) small size of the water molecules.
B) high specific heat of oxygen and hydrogen atoms.
C) absorption and release of heat when hydrogen bonds break and form.
D) fact that water is a poor heat conductor.
E) higher density of liquid water than solid water (ice).

Answer: C

Which type of bond must be broken for water to vaporize?
A) ionic bonds
B) both hydrogen bonds and ionic bonds
C) polar covalent bonds
D) hydrogen bonds
E) both polar covalent bonds and hydrogen bonds

Answer: D

Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
A) the change in density when it condenses to form a liquid or solid
B) reactions with other atmospheric compounds
C) the release of heat by the formation of hydrogen bonds
D) the release of heat by the breaking of hydrogen bonds
E) the high surface tension of water

Answer: C

Why does evaporation of water from a surface cause cooling of the surface?
A) The breaking of bonds between water molecules absorbs heat.
B) The water molecules with the most heat energy evaporate more readily.
C) The solute molecules left behind absorb heat.
D) Water molecules absorb heat from the surface in order to acquire enough energy to evaporate.
E) The expansion of water vapor extracts heat from the surface.

Answer: B

Why does ice float in liquid water?
A) The high surface tension of liquid water keeps the ice on top.
B) The ionic bonds between the molecules in ice prevent the ice from sinking.
C) Ice always has air bubbles that keep it afloat.
D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
E) The crystalline lattice of ice causes it to be denser than liquid water.

Answer: D

Hydrophobic substances such as vegetable oil are
A) nonpolar substances that repel water molecules.
B) nonpolar substances that have an attraction for water molecules.
C) polar substances that repel water molecules.
D) polar substances that have an affinity for water.
E) charged molecules that hydrogen-bond with water molecules.

Answer: A

One mole (mol) of glucose (molecular mass = 180 daltons) is
A) 180 × 10²³ molecules of glucose.
B) 1 kg of glucose dissolved in 1 L of solution.
C) the largest amount of glucose that can be dissolved in 1 L of solution.
D) 180 kilograms of glucose.
E) both 180 grams of glucose and 6.02 × 10²³ molecules of glucose.

Answer: E

How many molecules of glucose (C₆H₁₂O₆ molecular mass = 180 daltons) would be present in 90 grams of glucose?
A) 90 × 10²³
B) (6.02/180) × 10²³
C) (6.02/90) × 10²³
D) (90 x 6.02) × 10²³
E) (90/180) × 6.02 × 10²³

Answer: E

How many molecules of glycerol (C₃H₈O₃; molecular mass = 92) would be present in 1 L of a 1 M glycerol solution?
A) 1 × 10⁶
B) 14 × 6.02 × 10²³
C) 92 × 6.02 × 10²³
D) 6.02 × 10²⁶
E) 6.02 × 10²³

Answer: E

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na⁺) and chloride ions (Cl⁻). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?
A) 1 L of 0.5 M NaCl
B) 1 L of 0.5 M glucose
C) 1 L of 1.0 M NaCl
D) 1 L of 1.0 M glucose
E) 1 L of 1.0 M NaCl and 1 L of 1.0 M glucose will contain equal numbers of solute particles.

Answer: C

The molar mass of glucose is 180 g/mol. Which of the following procedures should you carry out to make a 1 M solution of glucose?
A) Dissolve 1 g of glucose in 1 L of water.
B) Dissolve 180 g of glucose in 1 L of water.
C) Dissolve 180 g of glucose in 180 g of water.
D) Dissolve 180 milligrams (mg) of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.8 L of water, and then add more water until the total volume of the solution is 1 L.

Answer: E

Section 3 1-20

The molar mass of glucose (C₆H₁₂O₆) is 180 g/mol. Which of the following procedures should you carry out to make a 0.5 M solution of glucose?
A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of solution is 1 L.
B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.
C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.
D) Dissolve 0.5 g of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.5 L of water.

Answer: B

You have a freshly prepared 0.1 M solution of glucose in water. Each liter of this solution contains how many glucose molecules?
A) 6.02 × 10²³
B) 3.01 × 10²³
C) 6.02 × 10²⁴
D) 12.04 × 10²³
E) 6.02 × 10²²

Answer: E

The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water? (Hint: What is the mass of 1 liter of pure water?)
A) 55.6 M
B) 18 M
C) 37 M
D) 0.66 M
E) 1.0 M

Answer: A

You have a freshly prepared 1 M solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample?
A) 6.02 × 10²³
B) 3.01 × 10²³
C) 6.02 × 10²⁴
D) 12.04 × 10²³
E) 6.02 × 10²²

Answer: E

A strong acid like HCl
A) ionizes completely in an aqueous solution.
B) increases the pH when added to an aqueous solution.
C) reacts with strong bases to create a buffered solution.
D) is a strong buffer at low pH.
E) both ionizes completely in aqueous solutions and is a strong buffer at low pH.

Answer: A

Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?
A) NaCl
B) HCl
C) NH₃
D) H₂CO₃
E) NaOH

Answer: E

A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?
A) It is a strong acid that ionizes completely in water.
B) It is a strong base that ionizes completely in water.
C) It is a weak acid.
D) It is a weak base.
E) It is neither an acid nor a base.

Answer: A

A given solution contains 0.0001(10⁻⁴) moles of hydrogen ions [H⁺] per liter. Which of the following best describes this solution?
A) acidic: will accept H⁺ from both strong and weak acids
B) basic: will accept H⁺ from both strong and weak acids
C) acidic: will give H⁺ to weak acids, but accept H+ from strong acids
D) basic: will give H⁺ to weak acids, but accept H⁺ from weak acids
E) acidic: will give H⁺ to both strong and weak acids

Answer: C

A solution contains 0.0000001(10⁻⁷) moles of hydroxyl ions [OH⁻] per liter. Which of the following best describes this solution?
A) acidic: H⁺ acceptor
B) basic: H⁺ acceptor
C) acidic: H⁺ donor
D) basic: H⁺ donor
E) neutral

Answer: E

What is the pH of a solution with a hydroxyl ion [OH⁻] concentration of 10⁻¹² M?
A) pH 2
B) pH 4
C) pH 10
D) pH 12
E) pH 14

Answer: A

What is the pH of a 1 millimolar NaOH solution?
A) pH 3
B) pH 8
C) pH 9
D) pH 10
E) pH 11

Answer: E

Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?
A) gastric juice at pH 2
B) vinegar at pH 3
C) tomato juice at pH 4
D) black coffee at pH 5
E) household bleach at pH 12

Answer: A

What is the hydrogen ion [H⁺] concentration of a solution of pH 8?
A) 8 M
B) 8 x 10⁻⁶ M
C) 0.01 M
D) 10⁻⁸ M
E) 10⁻⁶ M

Answer: D

If the pH of a solution is decreased from 9 to 8, it means that the
A) concentration of H⁺ has decreased to one-tenth (1/10) what it was at pH 9.
B) concentration of H⁺ has increased tenfold (10X) compared to what it was at pH 9.
C) concentration of OH⁻ has increased tenfold (10X) compared to what it was at pH 9.
D) concentration of OH⁻ has decreased to one-tenth (1/10) what it was at pH 9.
E) concentration of H⁺ has increased tenfold (10X) and the concentration of OH⁻ has decreased to one-tenth (1/10) what they were at pH 9.

Answer: E

If the pH of a solution is increased from pH 5 to pH 7, it means that the
A) concentration of H⁺ is twice (2X) what it was at pH 5.
B) concentration of H⁺ is one-half (1/2) what it was at pH 5.
C) concentration of OH⁻ is 100 times greater than what it was at pH 5.
D) concentration of OH⁻ is one-hundredth (0.01X) what it was at pH 5.
E) concentration of H⁺ is 100 times greater and the concentration of OH⁻ is one-hundredth what they were at pH 5.

Answer: C

One liter of a solution of pH 2 has how many more hydrogen ions (H⁺) than 1 L of a solution of pH 6?
A) 4 times more
B) 16 times more
C) 40,000 times more
D) 10,000 times more
E) 100,000 times more

Answer: D

One liter of a solution of pH 9 has how many more hydroxyl ions (OH⁻) than 1 L of a solution of pH 4?
A) 5 times more
B) 32 times more
C) 50,000 times more
D) 10,000 times more
E) 100,000 times more

Answer: E

Which of the following statements is true about buffer solutions?
A) They maintain a constant pH when bases are added to them but not when acids are added to them.
B) They maintain a constant pH when acids are added to them but not when bases are added to them.
C) They maintain a relatively constant pH of approximately 7 when either acids or bases are added to them.
D) They maintain a relatively constant pH when either acids or bases are added to them.
E) They are found only in living systems and biological fluids.

Answer: D

Buffers are substances that help resist shifts in pH by
A) releasing H⁺ to a solution when acids are added.
B) donating H⁺ to a solution when bases are added.
C) releasing OH⁻ to a solution when bases are added.
D) accepting H⁺ from a solution when acids are added.
E) both donating H⁺ to a solution when bases are added, and accepting H⁺ when acids are added.

Answer: E

One of the buffers that contribute to pH stability in human blood is carbonic acid (H₂CO₃). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO₃⁻) and a hydrogen ion (H⁺). Thus,

H₂CO₃ ↔ HCO₃⁻ + H⁺

If the pH of the blood drops, one would expect
A) a decrease in the concentration of H₂CO₃ and an increase in the concentration of HCO₃⁻.
B) the concentration of hydroxide ion (OH⁻) to increase.
C) the concentration of bicarbonate ion (HCO₃⁻) to increase.
D) the HCO₃⁻ to act as a base and remove excess H⁺ with the formation of H₂CO₃.
E) the HCO₃⁻ to act as an acid and remove excess H⁺ with the formation of H₂CO₃.

Answer: D

Section 3 21-40

One of the buffers that contribute to pH stability in human blood is carbonic acid (H₂CO₃). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO₃⁻ and a hydrogen ion (H⁺). Thus, H₂CO₃ ↔ HCO₃⁻ + H⁺ If the pH of the blood increases, one would expect A) a decrease in the concentration of H₂CO₃ and an increase in the concentration of HCO₃⁻. B) an increase in the concentration of H₂CO₃ and a decrease in the concentration of HCO₃⁻. C) a decrease in the concentration of HCO₃⁻ and an increase in the concentration of H⁺. D) an increase in the concentration of HCO₃⁻ and a decrease in the concentration of OH⁻. E) a decrease in the concentration of HCO₃⁻ and an increase in the concentration of both HH₂CO₃ and H⁺. Answer: A 42 Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake? A) 1 × 10⁻¹⁰ mol of hydroxyl ion per liter of lake water B) 1 × 10⁻⁴ mol of hydroxyl ion per liter of lake water C) 10.0 M with regard to hydroxyl ion concentration D) 4.0 M with regard to hydroxyl ion concentration E) 1 × 10⁻⁴ mol of hydroxyl ion per liter of lake water and 4.0 M with regard to hydrogen ion concentration Answer: A 43 Research indicates that acid precipitation can damage living organisms by A) buffering aquatic systems such as lakes and streams. B) decreasing the H⁺ concentration of lakes and streams. C) increasing the OH⁻ concentration of lakes and streams. D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth. E) both decreasing the H⁺ concentration of lakes and streams and increasing the OH⁻ concentration of lakes and streams. Answer: D 44 Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that A) solution Y has no free hydrogen ions (H⁺). B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y. C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X. D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y. E) the concentration of hydrogen ions in solution X is 1,000 times as great as the concentration of hydrogen ions in solution Y. Answer: E 45 If a solution has a pH of 7, this means that A) there are no H⁺ ions in the water. B) this is a solution of pure water. C) the concentration of H⁺ ions in the water equals the concentration of OH⁻ ions in the water. D) this is a solution of pure water, and the concentration of H⁺ ions in the water is 10⁻⁷ M. E) this is a solution of pure water, and the concentration of H⁺ ions equals the concentration of OH⁻ ions in the water. Answer: C 46 Carbon dioxide (CO₂) is readily soluble in water, according to the equation CO₂ + H₂O ↔ H₂CO₃. Carbonic acid (H₂CO₃) is a weak acid. Respiring cells release CO₂ into the bloodstream. What will be the effect on pH of blood as that blood first comes in contact with respiring cells? A) Blood pH will decrease slightly. B) Blood pH will increase slightly. C) Blood pH will remain unchanged. D) Blood pH will first increase, then decrease as CO₂ combines with hemoglobin. E) Blood pH will first decrease, then increase sharply as CO₂ combines with hemoglobin. Answer: A 47 A beaker contains 100 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing? A) The concentration of Na⁺ ion rises. B) The concentration of Cl⁻ ion will be 0.1 M. C) The concentration of undissociated H₂O molecules remains unchanged. D) The pH of the beaker's contents will be neutral. E) The pH of the beaker's contents falls. Answer: E 48 Equal volumes (5 mL) of vinegar from a freshly opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH? A) 100 mL of pure water B) 100 mL of freshly brewed coffee C) 100 mL of household cleanser containing 0.5 M ammonia D) 100 mL of freshly squeezed orange juice E) 100 mL of tomato juice Answer: C 49 Increased atmospheric CO₂ concentrations might have what effect on seawater? A) Seawater will become more acidic, and bicarbonate concentrations will decrease. B) Seawater will become more alkaline, and carbonate concentrations will decrease. C) There will be no change in the pH of seawater, because carbonate will turn to bicarbonate. D) Seawater will become more acidic, and carbonate concentrations will decrease. E) Seawater will become more acidic, and carbonate concentrations will increase. Answer: D 50 How would acidification of seawater affect marine organisms? A) Acidification would increase dissolved carbonate concentrations and promote faster growth of corals and shell-building animals. B) Acidification would decrease dissolved carbonate concentrations and promote faster growth of corals and shell-building animals. C) Acidification would increase dissolved carbonate concentrations and hinder growth of corals and shell-building animals. D) Acidification would decrease dissolved carbonate concentrations and hinder growth of corals and shell-building animals. E) Acidification would increase dissolved bicarbonate concentrations, and cause increased calcification of corals and shellfish. Answer: D 51 One idea to mitigate the effects of burning fossil fuels on atmospheric CO₂ concentrations is to pipe liquid CO₂ into the ocean at depths of 2,500 feet or greater. At the high pressures at such depths, CO₂ is heavier than water. What potential effects might result from implementing such a scheme? A) increased photosynthetic carbon fixation because of the increased dissolved carbon dioxide in the deep water B) increased carbonate concentrations in the deep waters C) reduced growth of corals from a change in the carbonate—bicarbonate equilibrium D) no effect because carbon dioxide is not soluble in water E) both increased acidity of the deep waters and changes in the growth of bottom-dwelling organisms with calcium carbonate shells Answer: E 52 If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that A) the concentration of H⁺ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix. B) the concentration of H⁺ ions is tenfold higher in the mitochondrial matrix than in the cytoplasm. C) the concentration of H⁺ ions in the cytoplasm is 7/8 the concentration in the mitochondrial matrix. D) the mitochondrial matrix is more acidic than the cytoplasm. E) the concentration of H⁺ ions in the cytoplasm is 8/7 the concentration in the mitochondrial matrix. Answer: A 53 Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is most likely A) positively charged. B) negatively charged. C) without charge. D) hydrophobic. E) nonpolar. Answer: A 54 How many grams would be equal to 1 mol of the compound shown in the figure above? (carbon = 12, oxygen = 16, hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 Answer: C 55 How many grams of the compound in the figure above would be required to make 1 L of a 0.5 M solution? (carbon = 12, oxygen = 16, hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 Answer: B 56 How m

section 3 41-60

You have two beakers. One contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen.
A) Equal amounts of NaCl crystals will dissolve in both water and methanol.
B) NaCl crystals will NOT dissolve in either water or methanol.
C) NaCl crystals will dissolve readily in water but will not dissolve in methanol.
D) NaCl crystals will dissolve readily in methanol but will not dissolve in water.
E) When the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more crystals are added, the crystals will begin to dissolve faster and faster.

Answer: C

You have two beakers. One contains a solution of HCl at pH = 1.0. The other contains a solution of NaOH at pH = 13. Into a third beaker, you slowly and cautiously pour 20 mL of the HCl and 20 mL of the NaOH. After complete stirring, the pH of the mixture will be
A) 2.0.
B) 12.0.
C) 7.0.
D) 5.0.
E) 9.0.

Answer: C

Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
A) water's change in density when it condenses
B) water's ability to dissolve molecules in the air
C) the release of heat by the formation of hydrogen bonds
D) the absorption of heat by the breaking of hydrogen bonds
E) water's high surface tension

Answer: D

The bonds that are broken when water vaporizes are
A) ionic bonds.
B) hydrogen bonds between water molecules.
C) covalent bonds between atoms within water molecules.
D) polar covalent bonds.
E) nonpolar covalent bonds.

Answer: B

Which of the following is a hydrophobic material?
A) paper
B) table salt
C) wax
D) sugar
E) pasta

Answer: C

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their
A) mass in daltons.
B) mass in grams.
C) volume.
D) number of atoms.
E) number of molecules.

Answer: E

Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?
A) 4.0 M
B) 10⁻¹⁰ M
C) 10⁻⁴ M
D) 10⁴ M
E) 4%

Answer: C

Measurements show that the pH of a particular lake is 4.0. What is the hydroxide ion concentration of the lake?
A) 10⁻¹⁰ M
B) 10⁻⁴ M
C) 10⁻⁷ M
D) 10⁻¹⁴ M
E) 10 M

Answer: A

A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.)
A) 50°C
B) 5°C
C) 1°C
D) 100°C
E) 10°C

Answer: E

How many grams of acetic acid (C₂H₄O₂) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.)
A) 10 g
B) 0.1 g
C) 6.0 g
D) 60 g
E) 0.6 g

Answer: D

Section 3 61-end

When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using
A) a phase-contrast light microscope.
B) a scanning electron microscope.
C) a transmission electronic microscope.
D) a confocal fluorescence microscope.
E) a super-resolution fluorescence microscope.

Answer: C

The advantage of light microscopy over electron microscopy is that
A) light microscopy provides for higher magnification than electron microscopy.
B) light microscopy provides for higher resolving power than electron microscopy.
C) light microscopy allows one to view dynamic processes in living cells.
D) light microscopy provides higher contrast than electron microscopy.
E) specimen preparation for light microcopy does not produce artifacts.

Answer: C

A primary objective of cell fractionation is to
A) view the structure of cell membranes.
B) sort cells based on their size and weight.
C) determine the size of various organelles.
D) separate the major organelles so that their particular functions can be determined.
E) separate lipid-soluble from water-soluble molecules.

Answer: D

In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is
A) the relative solubility of the component.
B) the size and weight of the component.
C) the percentage of carbohydrates in the component.
D) the presence or absence of nucleic acids in the component.
E) the presence or absence of lipids in the component.

Answer: B

Which of the following correctly lists the order in which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge?
A) ribosomes, nucleus, mitochondria
B) chloroplasts, ribosomes, vacuoles
C) nucleus, ribosomes, chloroplasts
D) vacuoles, ribosomes, nucleus
E) nucleus, mitochondria, ribosomes

Answer: E

Green fluorescent protein (GFP) can be used to fluorescently label a specific protein in cells by genetically engineering cells to synthesize the target protein fused to GFP. What is the advantage of using GFP fusions to visualize specific proteins, instead of staining cells with fluorescently labeled probes that bind to the target protein?
A) GFP fusions enable one to track changes in the location of the protein in living cells; staining usually requires preserved cells.
B) GFP fusions enable higher resolution than staining with fluorescent probes.
C) GFP permits the position of the protein in the cell more precisely than fluorescent probes.
D) GFP permits visualization of protein-protein interactions; fluorescent probes do not.
E) GFP fusions are not subject to artifacts; fluorescent probes may introduce background artifacts.

Answer: A

What is the reason that a modern electron microscope (TEM) can resolve biological images to the subnanometer level, as opposed to tens of nanometers achievable for the best super-resolution light microscope?
A) The focal length of the electron microscope is significantly longer.
B) Contrast is enhanced by staining with atoms of heavy metal.
C) Electron beams have much shorter wavelengths than visible light.
D) The electron microscope has a much greater ratio of image size to real size.
E) The electron microscope cannot image whole cells at one time.

Answer: C

What technique would be most appropriate to use to observe the movements of condensed chromosomes during cell division?
A) light microscopy
B) scanning electron microscopy
C) transmission electron microscopy
D) confocal fluorescence microscopy
E) super-resolution fluorescence microscopy

Answer: A

All of the following are part of a prokaryotic cell except
A) DNA.
B) a cell wall.
C) a plasma membrane.
D) ribosomes.
E) an endoplasmic reticulum.

Answer: E

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that
A) plant cells are capable of having a much higher surface-to-volume ratio than animal cells.
B) plant cells have a much more highly convoluted (folded) plasma membrane than animal cells.
C) plant cells contain a large vacuole that reduces the volume of the cytoplasm.
D) animal cells are more spherical, whereas plant cells are elongated.
E) plant cells can have lower surface-to-volume ratios than animal cells because plant cells synthesize their own nutrients.

Answer: C

A mycoplasma is an organism with a diameter between 0.1 and 1.0 µm. What does the organism's size tell you about how it might be classified?
A) It must be a single-celled protist.
B) It must be a single-celled fungus.
C) It could be almost any typical bacterium.
D) It could be a typical virus.
E) It could be a very small bacterium.

Answer: E

Which of the following is a major cause of the size limits for certain types of cells?
A) limitation on the strength and integrity of the plasma membrane as cell size increases
B) the difference in plasma membranes between prokaryotes and eukaryotes
C) evolutionary progression in cell size; more primitive cells have smaller sizes
D) the need for a surface area of sufficient area to support the cell's metabolic needs
E) rigid cell walls that limit cell size expansion

Answer: D

Which of the following statements concerning bacteria and archaea cells is correct?
A) Archaea cells contain small membrane-enclosed organelles; bacteria do not.
B) Archaea cells contain a membrane-bound nucleus; bacteria do not.
C) DNA is present in both archaea cells and bacteria cells.
D) DNA is present in the mitochondria of both bacteria and archaea cells.

Answer: A

The evolution of eukaryotic cells most likely involved
A) endosymbiosis of an aerobic bacterium in a larger host cell–the endosymbiont evolved into mitochondria.
B) anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygen–the anaerobic bacterium evolved into chloroplasts.
C) an endosymbiotic fungal cell evolved into the nucleus.
D) acquisition of an endomembrane system, and subsequent evolution of mitochondria from a portion of the Golgi.

Answer: A

Prokaryotes are classified as belonging to two different domains. What are the domains?
A) Bacteria and Eukarya
B) Bacteria and Archaea
C) Archaea and Protista
D) Bacteria and Protista
E) Bacteria and Fungi

Answer: B

If radioactive deoxythymidine triphosphate (dTTP) is added to a culture of rapidly growing bacterial cells, where in the cell would you expect to find the greatest concentration of radioactivity?
A) nucleus
B) cytoplasm
C) endoplasmic reticulum
D) nucleoid
E) ribosomes

Answer: D

Which organelle or structure is absent in plant cells?
A) mitochondria
B) Golgi vesicles
C) microtubules
D) centrosomes
E) peroxisomes

Answer: D

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
A) lipids
B) glycogen
C) proteins
D) cellulose
E) nucleic acids

Answer: C

The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely consequence?
A) the loss of all nuclear function
B) the inability of the nucleus to divide during cell division
C) a change in the shape of the nucleus
D) failure of chromosomes to carry genetic information
E) inability of the nucleus to keep out destructive chemicals

Answer: C

Recent evidence shows that when chromosomes decondense during interphase, their DNA molecules do not intermingle. Instead, they occupy distinct territories within the nucleus. Considering the structure and location of the following structures, which is most likely to be involved in chromosome location?
A) nuclear pores
B) the nucleolus
C) microfilaments
D) the nuclear lamina
E) the nuclear matrix

Answer: E

Section 6 1-20

A cell with a predominance of free ribosomes is most likely
A) producing primarily proteins for secretion.
B) producing primarily cytoplasmic proteins.
C) constructing an extensive cell wall or extracellular matrix.
D) digesting large food particles.
E) enlarging its vacuole.

Answer: B

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?
A) ribosome
B) lysosome
C) smooth endoplasmic reticulum
D) mitochondrion
E) contractile vacuole

Answer: C

Which structure is the site of the synthesis of proteins that may be exported from the cell?
A) rough ER
B) lysosomes
C) plasmodesmata
D) Golgi vesicles
E) free cytoplasmic ribosomes

Answer: A

The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity?
A) Transport vesicles fuse with one side of the Golgi and leave from the opposite side.
B) Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
C) Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
D) Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
E) All of the above correctly describe polar characteristics of the Golgi function.

Answer: E

The fact that the outer membrane of the nuclear envelope has bound ribosomes allows one to most reliably conclude that
A) at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope.
B) the nuclear envelope is not part of the endomembrane system.
C) the nuclear envelope is physically separated from the endoplasmic reticulum.
D) small vesicles from the Golgi fuse with the nuclear envelope.
E) nuclear pore complexes contain proteins.

Answer: A

The difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by
A) the physical separation of most membranes from each other.
B) the transportation of membrane lipids among the endomembrane system by small membrane vesicles.
C) the function of the Golgi apparatus in sorting and directing membrane components.
D) the modification of the membrane components once they reach their final destination.
E) the synthesis of different lipids and proteins in each of the organelles of the endomembrane system.

Answer: C

Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells?
A) chloroplast
B) lysosome
C) central vacuole
D) peroxisome
E) glyoxysome

Answer: B

Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells?
A) Prokaryotes are unlikely to be able to secrete proteins because they lack an endomembrane system.
B) The mechanism of protein secretion in prokaryotes is probably the same as that in eukaryotes.
C) Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.
D) In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are located outside of the cell.
E) Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell.

Answer: C

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large and complex lipids. Which cellular organelle must be involved in this condition?
A) the endoplasmic reticulum
B) the Golgi apparatus
C) the lysosome
D) mitochondria
E) membrane-bound ribosomes

Answer: C

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?
A) rough ER
B) smooth ER
C) Golgi apparatus
D) nuclear envelope
E) transport vesicles

Answer: B

Which of the following produces and modifies polysaccharides that will be secreted?
A) lysosome
B) vacuole
C) mitochondrion
D) Golgi apparatus
E) peroxisome

Answer: D

Which of the following contains hydrolytic enzymes?
A) lysosome
B) vacuole
C) mitochondrion
D) Golgi apparatus
E) peroxisome

Answer: A

Which organelle often takes up much of the volume of a plant cell?
A) lysosome
B) vacuole
C) mitochondrion
D) Golgi apparatus
E) peroxisome

Answer: B

Which organelle is the primary site of ATP synthesis in eukaryotic cells?
A) lysosome
B) vacuole
C) mitochondrion
D) Golgi apparatus
E) peroxisome

Answer: C

Which plant cell organelle contains its own DNA and ribosomes?
A) glyoxysome
B) vacuole
C) mitochondrion
D) Golgi apparatus
E) peroxisome

Answer: C

Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen?
A) lysosome
B) vacuole
C) mitochondrion
D) Golgi apparatus
E) peroxisome

Answer: E

Thylakoids, DNA, and ribosomes are all components found in
A) vacuoles.
B) chloroplasts.
C) mitochondria.
D) lysosomes.
E) nuclei.

Answer: B

In a plant cell, DNA may be found
A) only in the nucleus.
B) only in the nucleus and mitochondria.
C) only in the nucleus and chloroplasts.
D) in the nucleus, mitochondria, and chloroplasts.
E) in the nucleus, mitochondria, chloroplasts, and peroxisomes.

Answer: D

The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria. In light of the endosymbiont theory for the evolutionary origin of mitochondria, where is most ATP synthesis likely to occur in prokaryotic cells?
A) in the cytoplasm
B) on the inner mitochondrial membrane
C) on the endoplasmic reticulum
D) on the plasma membrane
E) on the inner nuclear envelope

Answer: D

One of the key innovations in the evolution of eukaryotes from a prokaryotic ancestor is the endomembrane system. What eukaryotic organelles or features might have evolved as a part of, or as an elaboration of, the endomembrane system?
A) plasma membrane
B) chloroplasts
C) mitochondria
D) nuclear envelope
E) none of these

Section 6 21-40

A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from
A) a bacterium.
B) an animal, but not a plant.
C) nearly any eukaryotic organism.
D) any multicellular organism, like a plant or an animal.
E) any kind of organism.

Answer: C

Which type of organelle is found in plant cells but not in animal cells?
A) ribosomes
B) mitochondria
C) nuclei
D) plastids
E) none of these

Answer: D

Why isn't the mitochondrion classified as part of the endomembrane system?
A) It is a static structure.
B) Its structure is not derived from the ER or Golgi.
C) It has too many vesicles.
D) It is not involved in protein synthesis.
E) It is not attached to the outer nuclear envelope.

Answer: B

In a liver cell detoxifying alcohol and some other poisons, the enzymes of the peroxisome remove hydrogen from these molecules and
A) combine the hydrogen with water molecules to generate hydrogen peroxide.
B) use the hydrogen to break down hydrogen peroxide.
C) transfer the hydrogen to the mitochondria.
D) transfer the hydrogen to oxygen molecules to generate hydrogen peroxide.

Answer: D

How does the cell multiply its peroxisomes?
A) They bud off from the Golgi.
B) They are brought into the cell from the environment.
C) They are built de novo from cytosol materials.
D) They split in two after they become sufficiently large.
E) The cell synthesizes hydrogen peroxide and encloses it in a membrane.

Answer: D

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
A) sites of energy production in cellular respiration
B) membrane proteins
C) ribosomes
D) cytoskeletal structures
E) cellulose fibers in the cell wall

Answer: D

Movement of vesicles within the cell depends on what cellular structures?
A) microtubules and motor proteins
B) actin filaments and microtubules
C) actin filaments and ribosomes
D) centrioles and motor proteins
E) actin filaments and motor proteins

Answer: A

The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is
A) a mitochondrion.
B) a microtubule.
C) a ribosome.
D) a microfilament.
E) a nuclear pore.

Answer: A

Which of the following contain the 9 + 2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules?
A) both motile cilia and primary (nonmotile) cilia
B) centrioles only
C) both flagella and motile cilia
D) both basal bodies and primary (nonmotile) cilia
E) both centrioles and basal bodies

Answer: C

Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to
A) form cleavage furrows during cell division.
B) migrate by amoeboid movement.
C) separate chromosomes during cell division.
D) extend pseudopods.
E) maintain the shape of the nucleus.

Answer: C

The differences among the three categories of cytoskeletal elements outlined in the table above would suggest that each of the following has specialized roles. Which of the following is a correct match? (All three elements are involved in the maintenance of cell shape.)
A) microfilaments and the nuclear lamina
B) microtubules and cleavage furrow formation
C) microfilaments and ciliary motion
D) intermediate filaments and cytoplasmic streaming
E) microtubules and chromosome movement

Answer: E

Centrioles, cilia, flagella, and basal bodies have remarkably similar structural elements and arrangements. Which of the following hypotheses is most plausible in light of such structural similarities?
A) Cilia and flagella arise from the centrioles.
B) Loss of basal bodies should lead to loss of all cilia, flagella, and centrioles.
C) Motor proteins such as dynein must have evolved before any of these four kinds of structure.
D) Cilia and flagella coevolved in the same ancestral eukaryotic organism.
E) Natural selection for cell motility repeatedly selected for microtubular arrays in circular patterns in the evolution of each of these structures.

Answer: A

If an individual has abnormal microtubules, due to a hereditary condition, in which organs or tissues would you expect dysfunction?
A) limbs, hearts, areas with a good deal of contraction
B) microvilli, alveoli, and glomeruli: cellular projections that increase surface area
C) all ducts, such as those from salivary or sebaceous glands, that transport fluids
D) sperm, larynx, and trachea: cells and tissues that contain flagella or cilia
E) phagocytic cells and white blood cells that exhibit amoeboid movement

Answer: D

Cytochalasin D is a drug that prevents actin polymerization. A cell treated with cytochalasin D will still be able to
A) perform amoeboid movement.
B) form cleavage furrows.
C) contract muscle fibers.
D) extend pseudopodia.
E) move vesicles around the cell.

Answer: E

Which of the following statements about the cytoskeleton is true?
A) The dynamic aspect of cytoskeletal function is made possible by the assembly and disassembly of a large variety of proteins into complex aggregates.
B) Microfilaments are structurally rigid and resist compression, whereas microtubules resist tension (stretching).
C) Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
D) Chemicals that block the assembly of the cytoskeleton would cause little effect on the cell's response to external signals and stimuli.
E) Transport vesicles among the membranes of the endomembrane system produce the cytoskeleton.

Answer: C

Cells require which of the following to form cilia or flagella?
A) centrosomes
B) laminin
C) actin
D) intermediate filaments
E) secretory vesicles

Answer: A

All of the following serve an important role in determining or maintaining the structure of plant cells. Which of the following are distinct from the others in their composition?
A) microtubules
B) microfilaments
C) plant cell walls
D) intermediate filaments
E) nuclear lamina

Answer: C

What do the cell walls of plants and the extracellular matrix of animal cells have in common?
A) They are largely composed of phospholipids and glycoproteins.
B) Their proteins are made by free cytoplasmic ribosomes.
C) They form rigid structures that provide structural support for cells but limit their expansion.
D) They limit the passage of small molecules.
E) They have functional connections with the cytoskeleton inside the cell.

Answer: E

The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic common to all of these extracellular structures?
A) They must block water and small molecules in order to regulate the exchange of matter and energy with their environment.
B) They must permit information transfer between the cell's cytoplasm and the nucleus.
C) They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume.
D) They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell.
E) They are composed of a mixture of lipids and carbohydrates.

Answer: D

When a potassium ion (K+) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion?
A) plasma membrane → primary cell wall → cytoplasm → vacuole
B) secondary cell wall → plasma membrane → primary cell wall → cytoplasm → vacuole
C) primary cell wall → plasma membrane → cytoplasm → vacuole
D) primary cell wall → plasma membrane → lysosome → cytoplasm → vacuole
E) primary cell wall → plasma membrane → cytoplasm → secondary cell wall → vacuole

Answer: C

Section 6 41-60

A mutation that disrupts the ability of an animal cell to add polysaccharide modifications to proteins would most likely cause defects in its
A) nuclear lamina and nuclear matrix.
B) nuclear matrix and extracellular matrix.
C) mitochondria and Golgi apparatus.
D) Golgi apparatus and extracellular matrix.
E) nuclear pores and secretory vesicles.

Answer: D

The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via which of the following?
A) gap junctions
B) the nucleus
C) DNA and RNA
D) integrins
E) plasmodesmata

Answer: D

Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells?
A) peroxisomes
B) desmosomes
C) gap junctions
D) extracellular matrix
E) tight junctions

Answer: C

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through
A) plasmodesmata.
B) intermediate filaments.
C) tight junctions.
D) desmosomes.
E) gap junctions.

Answer: E

Which of the following makes it necessary for animal cells, although they have no cell walls, to have intercellular junctions?
A) Cell membranes do not distinguish the types of ions and molecules passing through them.
B) Large molecules, such as proteins and RNA molecules, do not readily get through one, much less two, adjacent cell membranes.
C) Cell-to-cell communication requires physical attachment of one cell to another.
D) Maintenance of tissue integrity and barriers to fluid leakage requires cells to adhere tightly to one another.
E) The relative shapelessness of animal cells requires a mechanism for keeping the cells aligned.

Answer: D

Recent evidence shows that signals from the extracellular matrix (ECM) can regulate the expression of genes in the cell nucleus. A likely mechanism is that
A) mechanical signals of the ECM can alter the cytoskeleton, which can alter intracellular signaling.
B) intracellular signals might cause changes in the fibronectin binding to the cell surface.
C) orientation of microtubules to the ECM can change gene activity.
D) integrins that receive signals from the ECM migrate to the nucleus.
E) proteoglycans in the ECM undergo endocytosis and produce intracellular signaling molecules.

Answer: A

Signals between the ECM and the cytoskeleton may be transmitted by
A) fibronectin.
B) proteoglycans.
C) integrins.
D) collagen.
E) middle lamella.

Answer: C

ECM proteins are made by ribosomes in which part of a eukaryotic cell?
A) mitochondria
B) cytoplasm
C) nuclear envelope
D) Golgi apparatus
E) rough ER

Answer: E

What types of proteins are not synthesized in the rough ER?
A) endoplasmic reticulum proteins
B) extracellular matrix proteins
C) secreted proteins
D) mitochondrial proteins
E) plasma membrane proteins

Answer: D

Which of the trees in this figure groups the domains according to similarities in cellular size and architecture?
A) A
B) B
C) C
D) D

Answer: A

biologist wants specifically to examine the surfaces of different types of cells in kidney tubules of small mammals. The cells in question can be distinguished by external shape, size, and 3-D characteristics. Which of the following would be the optimum method for her study?
A) transmission electron microscopy
B) cell fractionation
C) light microscopy using stains specific to kidney function
D) light microscopy of living unstained material
E) scanning electron microscopy

Answer: E

A newspaper ad for a local toy store indicates that a very inexpensive microscope available for a small child is able to magnify specimens nearly as much as the much more costly microscope available in your college lab. What is the primary reason for the price difference?
A) The ad agency is misrepresenting the ability of the toy microscope to magnify.
B) The toy microscope does not have the same fine control for focus of the specimen.
C) The toy microscope magnifies a good deal, but has low resolution and therefore poor quality images.
D) The college microscope produces greater contrast in the specimens.
E) The toy microscope usually uses a different wavelength of light source.

Answer: C

A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, whereas organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively,
A) mitochondria and chloroplasts.
B) chloroplasts and peroxisomes.
C) peroxisomes and chloroplasts.
D) chloroplasts and mitochondria.
E) mitochondria and peroxisomes.

Answer: D

Which structure is not part of the endomembrane system?
A) nuclear envelope
B) chloroplast
C) Golgi apparatus
D) plasma membrane
E) ER

Answer: B

Which structure is common to plant and animal cells?
A) chloroplast
B) wall made of cellulose
C) central vacuole
D) mitochondrion
E) centriole

Answer: D

Which of the following is present in a prokaryotic cell?
A) mitochondrion
B) ribosome
C) nuclear envelope
D) chloroplast
E) ER

Answer: B

Which structure-function pair is mismatched?
A) nucleolus; production of ribosomal subunits
B) lysosome; intracellular digestion
C) ribosome; protein synthesis
D) Golgi; protein trafficking
E) microtubule; muscle contraction

Answer: E

Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the
A) mitochondria.
B) ribosomes.
C) peroxisomes.
D) lysosomes.
E) endoplasmic reticulum.

Answer: A

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
A) ER → Golgi → nucleus
B) Golgi →ER →lysosome
C) nucleus →ER →Golgi
D) ER →Golgi →vesicles that fuse with plasma membrane
E) ER →lysosomes →vesicles that fuse with plasma membrane

Answer: D

Which cell would be best for studying lyosomes?
A) muscle cell
B) nerve cell
C) phagocytic white blood cell
D) leaf cell of a plant
E) bacterial cell

Answer: C

Section 6 61-80

Humans and mice differ because
A) their cells have different small organic molecules.
B) their cells make different types of large biological molecules.
C) their cells make different types of lipids.
D) their cells have some differences in the sequence of nucleotides in their nucleic acids.
E) their cells make different types of proteins.

Answer: D

Molecules with which functional groups may form polymers via dehydration reactions?
A) hydroxyl groups
B) carbonyl groups
C) carboxyl groups
D) either carbonyl or carboxyl groups
E) either hydroxyl or carboxyl groups

Answer: E

Which of these molecules is not formed by dehydration reactions?
A) fatty acids
B) disaccharides
C) DNA
D) protein
E) amylose

Answer: A

) In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. Only a small portion of these monomers are used for synthesis of new macromolecules. The net result is that
A) water is generated by animal metabolism.
B) water is consumed by animal metabolism.
C) the water consumed is exactly balanced by the water generated, to maintain homeostasis.
D) water is consumed during homeostasis, but water is generated during periods of growth.
E) water is generated during homeostasis, but water is consumed during periods of growth.

Answer: B

Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?
A) lipids
B) carbohydrates
C) proteins
D) nucleic acids
E) lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers

Answer: B

Which of the following is not a polymer?
A) glucose
B) starch
C) cellulose
D) chitin
E) DNA

Answer: A

What is the chemical reaction mechanism by which cells make polymers from monomers?
A) phosphodiester linkages
B) hydrolysis
C) dehydration reactions
D) ionic bonding of monomers
E) the formation of disulfide bridges between monomers

Answer: C

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
A) 12
B) 11
C) 10
D) 9
E) 8

Answer: C

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
B) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable.
C) Dehydration reactions can occur only after hydrolysis.
D) Hydrolysis creates monomers, and dehydration reactions break down polymers.
E) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers.

Answer: A

Which of the following polymers contain nitrogen?
A) starch
B) glycogen
C) cellulose
D) chitin
E) amylopectin

Answer: D

The molecular formula for glucose is C₆H₁2O₆. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
A) C₁₈H₃₆O₁₈
B) C₁₈H₃₂O₁₆
C) C₆H₁₀O₅
D) C1₈H₁₀O₁₅
E) C₃H₆O₃

Answer: B

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?
A) glycogen
B) cellulose
C) chitin
D) glycogen and chitin only
E) glycogen, cellulose, and chitin

Answer: A

On food packages, to what does the term insoluble fiber refer?
A) cellulose
B) polypeptides
C) starch
D) amylopectin
E) chitin

Answer: A

A molecule with the chemical formula C₆H₁₂O₆ is probably a
A) carbohydrate.
B) lipid.
C) monosaccharide
D) carbohydrate and lipid only.
E) carbohydrate and monosaccharide only.

Answer: E

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
A) as a pentose
B) as a hexose
C) as a monosaccharide
D) as a disaccharide
E) as a polysaccharide

Answer: D

All of the following are polysaccharides except
A) lactose.
B) glycogen.
C) chitin.
D) cellulose.
E) amylopectin.

Answer: A

of the following is true of both starch and cellulose?
A) They are both polymers of glucose.
B) They are cis-trans isomers of each other.
C) They can both be digested by humans.
D) They are both used for energy storage in plants.
E) They are both structural components of the plant cell wall.

Answer: A

Which of the following is true of cellulose?
A) It is a polymer composed of enantiomers of glucose.
B) It is a storage polysaccharide for energy in plant cells.
C) It is digestible by bacteria in the human gut.
D) It is a major structural component of plant cell walls.
E) It is a polymer composed of enantiomers of glucose, it is a storage polysaccharide for energy in plant cells, it is digestible by bacteria in the human gut, and it is a major structural component of plant cell walls.

Answer: D

Humans can digest starch but not cellulose because
A) the monomer of starch is glucose, while the monomer of cellulose is galactose.
B) humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose.
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.
D) humans harbor starch-digesting bacteria in the digestive tract.
E) the monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group.

Answer: C

Which of the following statements concerning saturated fats is not true?
A) They are more common in animals than in plants.
B) They have multiple double bonds in the carbon chains of their fatty acids.
C) They generally solidify at room temperature.
D) They contain more hydrogen than unsaturated fats having the same number of carbon atoms.
E) They are one of several factors that contribute to atherosclerosis.

Answer: B

Section 5 1-20

A molecule with the formula C₁₈H3₆O₂ is probably a
A) carbohydrate.
B) fatty acid.
C) protein.
D) nucleic acid.
E) hydrocarbon.

Answer: B

Which of the following statements is true for the class of biological molecules known as lipids?
A) They are insoluble in water.
B) They are made from glycerol, fatty acids, and phosphate.
C) They contain less energy than proteins and carbohydrates.
D) They are made by dehydration reactions.
E) They contain nitrogen.

Answer: A

The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil?
A) The hydrogenated vegetable oil has a lower melting point.
B) The hydrogenated vegetable oil stays solid at room temperature.
C) The hydrogenated vegetable oil has more "kinks" in the fatty acid chains.
D) The hydrogenated vegetable oil has fewer trans fatty acids.
E) The hydrogenated vegetable oil is less likely to clog arteries.

Answer: B

Which of the following is true regarding saturated fatty acids?
A) They are the predominant fatty acid in corn oil.
B) They have double bonds between carbon atoms of the fatty acids.
C) They are the principal molecules in lard and butter.
D) They are usually liquid at room temperature.
E) They are usually produced by plants.

Answer: C

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?
A) a steroid
B) cellulose
C) DNA
D) an enzyme
E) a contractile protein

Answer: A

Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?
A) creating cis double bonds to the fatty acids
B) adding hydrogens to the fatty acids
C) creating trans double bonds to the fatty acids
D) adding hydrogens and trans double bonds to the fatty acids
E) adding cis double bonds and trans double bonds to the fatty acids

Answer: D

Why are human sex hormones considered to be lipids?
A) They are essential components of cell membranes.
B) They are not soluble in water.
C) They are made of fatty acids.
D) They are hydrophilic compounds.
E) They contribute to atherosclerosis.

Answer: B

All of the following contain amino acids except
A) hemoglobin.
B) cholesterol.
C) antibodies.
D) enzymes.
E) insulin.

Answer: B

) The bonding of two amino acid molecules to form a larger molecule requires
A) the release of a water molecule.
B) the release of a carbon dioxide molecule.
C) the addition of a nitrogen atom.
D) the addition of a water molecule.
E) the release of a nitrous oxide molecule.

Answer: A

There are 20 different amino acids. What makes one amino acid different from another?
A) different side chains (R groups) attached to a carboxyl carbon
B) different side chains (R groups) attached to the amino groups
C) different side chains (R groups) attached to an α carbon
D) different structural and optical isomers
E) different asymmetric carbons

Answer: C

The bonding of two amino acid molecules to form a larger molecule requires which of the following?
A) removal of a water molecule
B) addition of a water molecule
C) formation of a glycosidic bond
D) formation of a hydrogen bond
E) both removal of a water molecule and formation of a hydrogen bond

Answer: A

) Polysaccharides, triacylglycerides, and proteins are similar in that they
A) are synthesized from monomers by the process of hydrolysis.
B) are synthesized from subunits by dehydration reactions.
C) are synthesized as a result of peptide bond formation between monomers.
D) are decomposed into their subunits by dehydration reactions.
E) all contain nitrogen in their monomer building blocks.

Answer: B

Dehydration reactions are used in forming which of the following compounds?
A) triacylglycerides
B) polysaccharides
C) proteins
D) triacylglycerides and proteins only
E) triacylglycerides, polysaccharides, and proteins

Answer: E

Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?
A) 101
B) 100
C) 99
D) 98
E) 97

Answer: C

What aspects of protein structure are stabilized or assisted by hydrogen bonds?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
E) secondary, tertiary, and quaternary structures, but not primary structure

Answer: E

How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?
A) 4¹²
B) 12²⁰
C) 240
D) 20
E) 20¹²

Answer: E

Which bonds are created during the formation of the primary structure of a protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bonds
D) phosphodiester bonds
E) peptide bonds, hydrogen bonds, and disulfide bonds

Answer: A

What maintains the secondary structure of a protein?
A) peptide bonds
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
C) disulfide bonds
D) hydrophobic interactions
E) hydrogen bonds between the R groups

Answer: B

Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?
A) hydrophobic interactions
B) disulfide bonds
C) ionic bonds
D) hydrogen bonds
E) peptide bonds

Answer: D

Which level of protein structure do the α helix and the β pleated sheet represent?
A) primary
B) secondary
C) tertiary
D) quaternary
E) primary, secondary, tertiary, and quaternary

Answer: B

Section 5 21-40

The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary structure is stabilized by
A) covalent bonds.
B) peptide bonds.
C) ionic bonds.
D) polar bonds.
E) hydrogen bonds.

Answer: E

The tertiary structure of a protein is the
A) bonding together of several polypeptide chains by weak bonds.
B) order in which amino acids are joined in a polypeptide chain.
C) unique three-dimensional shape of the fully folded polypeptide.
D) organization of a polypeptide chain into an α helix or β pleated sheet.
E) overall protein structure resulting from the aggregation of two or more polypeptide subunits.

Answer: C

What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three-dimensional shape?
A) ionic bond
B) hydrophobic interaction
C) van der Waals interaction
D) disulfide bond
E) hydrogen bond

Answer: D

At which level of protein structure are interactions between the side chains (R groups) most important?
A) primary
B) secondary
C) tertiary
D) quaternary
E) all of the above

Answer: C

The R group or side chain of the amino acid serine is –CH₂–OH. The R group or side chain of the amino acid leucine is –CH₂–CH–(CH₃)₂. Where would you expect to find these amino acids in a globular protein in aqueous solution?
A) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
C) Both serine and leucine would be in the interior of the globular protein.
D) Both serine and leucine would be on the exterior of the globular protein.
E) Both serine and leucine would be in the interior and on the exterior of the globular protein.

Answer: B

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?
A) Alzheimer's only
B) Parkinson's only
C) diabetes mellitus only
D) Alzheimer's and Parkinson's only
E) Alzheimer's, Parkinson's, and diabetes mellitus

Answer: D

Changing a single amino acid in a protein consisting of 325 amino acids would
A) alter the primary structure of the protein, but not its tertiary structure or function.
B) cause the tertiary structure of the protein to unfold.
C) always alter the biological activity or function of the protein.
D) always alter the primary structure of the protein and disrupt its biological activity.
E) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and affect its biological activity.

Answer: E

Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits
A) altered primary structure.
B) altered secondary structure.
C) altered tertiary structure.
D) altered quaternary structure.
E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.

Answer: E

What methods may be used to elucidate the structures of purified proteins?
A) X-ray crystallography
B) bioinformatics
C) analysis of amino acid sequence of small fragments
D) NMR spectroscopy
E) both X-ray crystallography and NMR spectroscopy

Answer: E

In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?
A) in the interior of the folded protein, away from water
B) on the exterior surface of the protein, interacting with water
C) in the transmembrane portion interacting with lipid fatty acid chains
D) in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains
E) anywhere in the protein, with equal probability

Answer: D

of the following techniques uses the amino acid sequences of polypeptides to predict a protein's three-dimensional structure?
A) X-ray crystallography
B) bioinformatics
C) analysis of amino acid sequence of small fragments
D) NMR spectroscopy
E) high-speed centrifugation

Answer: B

If cells are grown in a medium containing radioactive ³⁵S, which of these molecules will be labeled?
A) phospholipids
B) nucleic acids
C) proteins
D) amylose
E) both proteins and nucleic acids

Answer: C

What is the term used for a protein molecule that assists in the proper folding of other proteins?
A) tertiary protein
B) chaperonin
C) enzyme protein
D) renaturing protein
E) denaturing protein

Answer: B

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?
A) The two strands of the double helix would separate.
B) The phosphodiester bonds between deoxyribose sugars would be broken.
C) The purines would be separated from the deoxyribose sugars.
D) The pyrimidines would be separated from the deoxyribose sugars.
E) All bases would be separated from the deoxyribose sugars.

Answer: B

Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct?
A) The 5' end has a hydroxyl group attached to the number 5 carbon of ribose.
B) The 5' end has a phosphate group attached to the number 5 carbon of ribose.
C) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base.
D) The 5' end has a carboxyl group attached to the number 5 carbon of ribose.
E) The 5' end is the fifth position on one of the nitrogenous bases.

Answer: B

One of the primary functions of RNA molecules is to
A) transmit genetic information to offspring.
B) function in the synthesis of proteins.
C) make a copy of itself, thus ensuring genetic continuity.
D) act as a pattern or blueprint to form DNA.
E) form the genes of higher organisms.

Answer: B

If ¹⁴C-labeled uridine triphosphate is added to the growth medium of cells, what macromolecules will be labeled?
A) phospholipids
B) DNA
C) RNA
D) both DNA and RNA
E) proteins

Answer: C

Which of the following descriptions best fits the class of molecules known as nucleotides?
A) a nitrogenous base and a phosphate group
B) a nitrogenous base and a pentose sugar
C) a nitrogenous base, a phosphate group, and a pentose sugar
D) a phosphate group and an adenine or uracil
E) a pentose sugar and a purine or pyrimidine

Answer: C

Which of the following are nitrogenous bases of the pyrimidine type?
A) guanine and adenine
B) cytosine and uracil
C) thymine and guanine
D) ribose and deoxyribose
E) adenine and thymine

Answer: B

Which of the following are nitrogenous bases of the purine type?
A) cytosine and guanine
B) guanine and adenine
C) adenine and thymine
D) thymine and uracil
E) uracil and cytosine

Answer: B

41-60

If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
A) 10
B) 20
C) 40
D) 80
E) impossible to tell from the information given

Answer: C

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of
A) 120 adenine and 120 uracil molecules.
B) 120 thymine and 120 adenine molecules.
C) 120 cytosine and 120 thymine molecules.
D) 120 adenine and 120 cytosine molecules.
E) 120 guanine and 120 thymine molecules.

Answer: B

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA
A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar.
B) can form a double-stranded molecule.
C) is an aldehyde sugar and the sugar in RNA is a keto sugar.
D) is in the α configuration and the sugar in RNA is in the β configuration.
E) contains one less oxygen atom.

Answer: E

Which of the following statements best summarizes the differences between DNA and RNA?
A) DNA encodes hereditary information, whereas RNA does not.
B) The bases in DNA form base-paired duplexes, whereas the bases in RNA do not.
C) DNA nucleotides contain a different sugar than RNA nucleotides.
D) DNA contains the base uracil, whereas RNA contains the base thymine.
E) DNA encodes hereditary information, whereas RNA does not; the bases in DNA form base-paired duplexes, whereas the bases in RNA do not; and DNA nucleotides contain a different sugar than RNA nucleotides.

Answer: C

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence
A) 5'TAACGT3'.
B) 5'TGCAAT3'.
C) 5'UAACGU3'.
D) 3'UAACGU5'.
E) 5'UGCAAU3'.

Answer: B

What is the structural feature that allows DNA to replicate?
A) sugar-phosphate backbone
B) complementary pairing of the nitrogenous bases
C) disulfide bonding (bridging) of the two helixes
D) twisting of the molecule to form an α helix
E) three-component structure of the nucleotides

Answer: B

A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism
A) is more closely related to humans than to frogs.
B) is more closely related to frogs than to humans.
C) evolved at about the same time as frogs, which is much earlier than primates and mammals.
D) is more closely related to humans than to rats.
E) is more closely related to frogs than to humans and also evolved at about the same time as frogs, which is much earlier than primates and mammals.

Answer: B

Which of the following is an example of hydrolysis?
A) the reaction of two monosaccharides, forming a disaccharide with the release of water
B) the synthesis of two amino acids, forming a peptide with the release of water
C) the reaction of a fat, forming glycerol and fatty acids with the release of water
D) the reaction of a fat, forming glycerol and fatty acids with the consumption of water
E) the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water

Answer: D

If cells are grown in a medium containing radioactive ³²P-labeled phosphate, which of these molecules will be labeled?
A) phospholipids
B) nucleic acids
C) proteins
D) amylose
E) both phospholipids and nucleic acids

Answer: E

If cells are grown in a medium containing radioactive ¹⁵N, which of these molecules will be labeled?
A) fatty acids only
B) nucleic acids only
C) proteins only
D) amylase only
E) both proteins and nucleic acids

Answer: E

How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?
A) DNA duplexes will unwind and separate.
B) Proteins will unfold (denature).
C) Starch will hydrolyze into monomeric sugars.
D) Proteins will hydrolyze into amino acids.
E) DNA duplexes will unwind and separate, and proteins will unfold (denature).

Answer: E

Which of the following is not a monomer/polymer pairing?
A) monosaccharide/polysaccharide
B) amino acid/protein
C) triglyceride/phospholipid bilayer
D) deoxyribonucleotide/DNA
E) ribonucleotide/RNA

Answer: C

If two molecules of the general type shown in Figure 5.1 were linked together, carbon-1 of one molecule to carbon-4 of the other, the single molecule that would result would be
A) maltose.
B) fructose.
C) glucose.
D) galactose.
E) sucrose.

Answer: A

Which of the following descriptors is true of the molecule shown in Figure 5.1?
A) hexose
B) fructose
C) glucose
D) hexose and fructose only
E) hexose and glucose only

Answer: E

Which of the following statements is true regarding the molecule illustrated in Figure 5.2?
A) It is a saturated fatty acid.
B) A diet rich in this molecule may contribute to atherosclerosis.
C) Molecules of this type are usually liquid at room temperature.
D) It is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis.
E) It is a saturated fatty acid, a diet rich in this molecule may contribute to atherosclerosis, and molecules of this type are usually liquid at room temperature.

Answer: D

Which of the following statements is true regarding the molecule illustrated in Figure 5.3?
A) It is a saturated fatty acid.
B) A diet rich in this molecule may contribute to atherosclerosis.
C) Molecules of this type are usually liquid at room temperature.
D) It is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis.
E) It is a saturated fatty acid, a diet rich in this molecule may contribute to atherosclerosis, and molecules of this type are usually liquid at room temperature.

Answer: C

The molecule shown in Figure 5.3 is a
A) polysaccharide.
B) polypeptide.
C) saturated fatty acid.
D) triacylglycerol.
E) unsaturated fatty acid.

Answer: E

What is the structure shown in Figure 5.4?
A) pentose molecule
B) fatty acid molecule
C) steroid molecule
D) oligosaccharide molecule
E) phospholipid molecule

Answer: C

Which of the following statements is/are true regarding the chemical reaction illustrated in Figure 5.5?
A) It is a hydrolysis reaction.
B) It results in a peptide bond.
C) It joins two fatty acids together.
D) It is a hydrolysis reaction and it results in a peptide bond.
E) It is a hydrolysis reaction, it results in a peptide bond, and it joins two fatty acids together.

Answer: B

At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acid?
A) A
B) B
C) C
D) D
E) E

61-80

Which bond is a peptide bond?
A) A
B) B
C) C
D) D
E) E

Answer: C

Which bond is closest to the amino terminus of the molecule?
A) A
B) B
C) C
D) D
E) E

Answer: A

The structure depicted in Figure 5.7 shows the
A) 1-4 linkage of the α glucose monomers of starch.
B) 1-4 linkage of the β glucose monomers of cellulose.
C) double-helical structure of a DNA molecule.
D) α helix secondary structure of a polypeptide.
E) β pleated sheet secondary structure of a polypeptide.

Answer: D

Which molecule has both hydrophilic and hydrophobic properties and would be found in plasma membranes?
A) 1
B) 5
C) 6
D) 12
E) 14

Answer: B

[SEE IMAGE FOR CARD #84]

Which of the following combinations could be linked together to form a nucleotide?
A) 1, 2, and 11
B) 3, 7, and 8
C) 5, 9, and 10
D) 11, 12, and 13
E) 12, 14, and 15

Answer: D

[SEE IMAGE FOR CARD #84]

Which of the following molecules contain(s) an aldehyde type of carbonyl functional group?
A) 1
B) 4
C) 8
D) 10
E) 1 and 4

Answer: E

[SEE IMAGE FOR CARD #84]

Which molecule is glycerol?
A) 1
B) 6
C) 10
D) 14
E) 15

Answer: C

[SEE IMAGE FOR CARD #84]

Which molecule is a saturated fatty acid?
A) 1
B) 5
C) 6
D) 8
E) 9

Answer: E

[SEE IMAGE FOR CARD #84]

Which of the following molecules is a purine type of nitrogenous base?
A) 2
B) 3
C) 5
D) 12
E) 13

Answer: E

[SEE IMAGE FOR CARD #84]

Which of the following molecules act as building blocks (monomers) of polypeptides?
A) 1, 4, and 6
B) 2, 7, and 8
C) 7, 8, and 13
D) 11, 12, and 13
E) 12, 13, and 15

Answer: B

[SEE IMAGE FOR CARD #84]

of the following molecules is an amino acid with a hydrophobic R group or side chain?
A) 3
B) 7
C) 8
D) 12
E) 13

Answer: B

[SEE IMAGE FOR CARD #84]

Which of the following molecules could be joined together by a peptide bond as a result of a dehydration reaction?
A) 2 and 3
B) 3 and 7
C) 7 and 8
D) 8 and 9
E) 12 and 13

Answer: C

[SEE IMAGE FOR CARD #84]

A fat (or triacylglycerol) would be formed as a result of a dehydration reaction between
A) one molecule of 9 and three molecules of 10.
B) three molecules of 9 and one molecule of 10.
C) one molecule of 5 and three molecules of 9.
D) three molecules of 5 and one molecule of 9.
E) one molecule of 5 and three molecules of 10.

Answer: B

[SEE IMAGE FOR CARD #84]

Which of the following molecules could be joined together by a phosphodiester type of covalent bond?
A) 3 and 4
B) 3 and 8
C) 6 and 15
D) 11 and 12
E) 11 and 13

Answer: D

[SEE IMAGE FOR CARD #84]

Which of the following molecules is the pentose sugar found in RNA?
A) 1
B) 4
C) 6
D) 12
E) 13

Answer: D

[SEE IMAGE FOR CARD #84]

Which of the following molecules contains a glycosidic linkage type of covalent bond?
A) 4
B) 6
C) 12
D) 13
E) 15

Answer: E

[SEE IMAGE FOR CARD #84]

Which of the following molecules has a functional group that frequently forms covalent bonds that maintain the tertiary structure of a protein?
A) 2
B) 3
C) 7
D) 8
E) 9

Answer: A

[SEE IMAGE FOR CARD #84]

Which of the following molecules consists of a hydrophilic "head" region and a hydrophobic "tail" region?
A) 2
B) 5
C) 7
D) 9
E) 11

Answer: B

[SEE IMAGE FOR CARD #84]

Which of the following statements is false?
A) Molecules 1 and 4 could be joined together by a glycosidic linkage to form a disaccharide.
B) Molecules 9 and 10 could be joined together by ester bonds to form a triacylglycerol.
C) Molecules 2 and 7 could be joined together to form a short peptide.
D) Molecules 2, 7, and 8 could be joined together to form a short peptide.
E) Molecules 14 and 15 could be joined together to form a polypeptide.

Answer: E

100

Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides.

Among these biological polymers, which has the least structural variety?
A) polysaccharides
B) proteins
C) DNA
D) RNA

81-100

Which class of biological polymer has the greatest functional variety?
A) polysaccharides
B) proteins
C) DNA
D) RNA

Answer: B

102

Professor Jamey Marth at the University of California, Santa Barbara, identified 70 molecules that are used to build cellular macromolecules and structures. These include at least 34 saccharides, 8 nucleosides, and 20 amino acids. In theory, then, which class of biological polymer has the greatest information-coding capacity?
A) polysaccharides
B) proteins
C) DNA
D) RNA

Answer: A

103

Which of the following categories includes all others in the list?
A) monosaccharide
B) disaccharide
C) starch
D) carbohydrate
E) polysaccharide

Answer: D

104

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the α form. Which of the following could amylase break down?
A) glycogen, starch, and amylopectin
B) glycogen and cellulose
C) cellulose and chitin
D) starch and chitin
E) starch, amylopectin, and cellulose

Answer: A

105

Which of the following statements concerning unsaturated fats is true?
A) They are more common in animals than in plants.
B) They have double bonds in the carbon chains of their fatty acids.
C) They generally solidify at room temperature.
D) They contain more hydrogen than do saturated fats having the same number of carbon atoms.
E) They have fewer fatty acid molecules per fat molecule.

Answer: B

106

The structural level of a protein least affected by a disruption in hydrogen bonding is the
A) primary level.
B) secondary level.
C) tertiary level.
D) quaternary level.
E) All structural levels are equally affected.

Answer: A

107

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?
A) The two strands of the double helix would separate.
B) The phosphodiester linkages of the polynucleotide backbone would be broken.
C) The purines would be separated from the deoxyribose sugars.
D) The pyrimidines would be separated from the deoxyribose sugars.
E) All bases would be separated from the deoxyribose sugars.

Answer: B

108

The molecular formula for glucose is C₆H₁₂O₆. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
A) C₆₀H₁₂₀O₆₀
B) C₆H₁₂O₆
C) C₆₀H₁₀₂O₅₁
D) C₆₀H₁₀₀O₅₀
E) C₆₀H₁₁₁O₅₁

Answer: C

109

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?
A) 5'-purine-pyrimidine-purine-pyrimidine-3' with 3'-purine-pyrimidine-purine-pyrimidine-5'
B) 5'-AGCT-3' with 5'-TCGA-3'
C) 5'-GCGC-3' with 5'-TATA-3'
D) 5'-ATGC-3' with 5'-GCAT-3'
E) All of these pairs are correct.

Answer: D

101-end