Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material and have their DNA encased within an nuclear envelope?

A) animal

B) plant

C) archaea

D) fungi

E) Protists

A

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

C

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.

D

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

C

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

E

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.

E

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

D

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

A

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.

A

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

D

Amino acids are acids because they always possess which functional group?
A) amino
B) carbonyl
C) carboxyl
D) phosphate
E) hydroxyl

C

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.

C

The two molecules shown in the figure above are best described as
A) enantiomers.
B) radioactive isotopes.
C) structural isomers.
D) nonisotopic isomers.
E) cis-trans isomers.

E

The main source of energy for producers in an ecosystem is
A) light energy
B) kinetic energy
C) thermal energy
D) chemical energy
E) ATP

A

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.

B

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

A

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⁺.

A

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.

C

The half-life of carbon-14 is 5730. If a sample contains 4 mg of carbon-14, how much will it contain in 17,190 years?

1

Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that
A) have identical chemical formulas but differ in the branching of their carbon skeletons.
B) are mirror images of one another.
C) exist in either linear chain or ring forms.
D) differ in the location of their double bonds.
E) differ in the arrangement of atoms around their double bonds.

B

A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it
A) would function only as an acid because of the carboxyl group.
B) would function only as a base because of the amino group.
C) would function as neither an acid nor a base.
D) would function as both an acid and a base.
E) is impossible to determine how it would function.

D

Three or four of the following illustrations depict different structural isomers of the organic compound with molecular formula C₆H₁₄. For clarity, only the carbon skeletons are shown; hydrogen atoms that would be attached to the carbons have been omitted. Which one, if any, is NOT a structural isomer of this compound?

C

What is the major difference between a kingdom and a domain?
A) A kingdom can include several subgroups known as domains.
B) All eukarya belong to one domain.
C) All prokaryotes belong to one domain.
D) The importance of fungi has led scientists to make them the whole of one domain.
E) Only organisms that produce their own food belong to one of the domains.

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.

B

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.

B

Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight into
A) the energy of motion
B) carbon dioxide and water
C) the potential energy of chemical bonds
D) oxygen
E) kinetic energy

C

A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?
A) Eukarya
B) Thermophile
C) Animalia
D) Protista
E) Fungi

B

How many structural isomers are possible for a substance having the molecular formula C₄H₁₀?
A) 1
B) 2
C) 4
D) 3
E) 11

B

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

E

A carbon atom is most likely to form what kind of bond(s) with other atoms?
A) ionic
B) hydrogen
C) covalent
D) covalent bonds and hydrogen bonds
E) ionic bonds, covalent bonds, and hydrogen bonds

C

The element present in all organic molecules is
A) hydrogen.
B) oxygen.
C) carbon.
D) nitrogen.
E) phosphorus.

C

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.

D

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

B

Testosterone and estradiol are
A) soluble in water.
B) structural isomers of each other.
C) proteins.
D) lipids.
E) enantiomers of each other.

B

How many electron pairs does carbon share in order to complete its valence shell?
A) 1
B) 2
C) 3
D) 4
E) 8

D

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
A) CO₂
B) an amino acid
C) glucose
D) K⁺
E) starch

A

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

A

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

A

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are
A) hypotonic to both fresh water and the salt solution.
B) hypertonic to both fresh water and the salt solution.
C) hypertonic to fresh water but hypotonic to the salt solution.
D) hypotonic to fresh water but hypertonic to the salt solution.
E) isotonic with fresh water but hypotonic to the salt solution

C

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.

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.

E

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

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.

B

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?

A) Golgi → ER → lysosome

B) ER → Golgi → nucleus

C) ER → Golgi → vesicles that fuse with plasma membrane

D) ER → lysosomes → vesicles that fuse with plasma membrane

E) nucleus → ER → Golgi

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

C

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.

D

Which of the following is present in a prokaryotic cell?

A) mitochondrion

B) ribosome

C) chloroplast

D) ER

B

Water passes quickly through cell membranes because
A) the bilayer is hydrophilic.
B) it moves through hydrophobic channels.
C) water movement is tied to ATP hydrolysis.
D) it is a small, polar, charged molecule.
E) it moves through aquaporins in the membrane.

E

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

C

In order for a protein to be an integral membrane protein it would have to be
A) hydrophilic.
B) hydrophobic.
C) amphipathic, with at least one hydrophobic region.
D) completely covered with phospholipids.
E) exposed on only one surface of the membrane

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

B

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 3D 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

E

When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that
A) the integral membrane proteins are not strong enough to hold the bilayer together.
B) water that is present in the middle of the bilayer freezes and is easily fractured.
C) hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing.
D) the carbon-carbon bonds of the phospholipid tails are easily broken.
E) the hydrophobic interactions that hold the membrane together are weakest at this point.

E

Which structure-function pair is mismatched? A)lysosome; intracellular digestion

B)microtubule; muscle contraction

C)ribosome; protein synthesis

D)Golgi; protein trafficking

E)nucleolus; production of ribosomal subunits

B

The difference between pinocytosis and receptor-mediated endocytosis is that
A) pinocytosis brings only water molecules into the cell, but receptor-mediated endocytosis brings in other molecules as well.
B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area.
C) pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity.
D) pinocytosis requires cellular energy, but receptor-mediated endocytosis does not.
E) pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot.

C

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

C

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

D

n a paramecium, cell surface integral membrane proteins are synthesized
A) in the cytoplasm by free ribosomes.
B) by ribosomes in the nucleus.
C) by ribosomes bound to the rough endoplasmic reticulum.
D) by ribosomes in the Golgi vesicles.
E) by ribosomes bound to the inner surface of the plasma membrane.

C

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

C

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

C

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

D

Which component is the peripheral protein?
A) A
B) B
C) C
D) D
E) E

D

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

A

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

B

Which of the following types of molecules are the major structural components of the cell membrane?
A) phospholipids and cellulose
B) nucleic acids and proteins
C) phospholipids and proteins
D) proteins and cellulose
E) glycoproteins and cholesterol

C

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.

E

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?
A) transporting ions against an electrochemical gradient
B) cell-cell recognition
C) maintaining fluidity of the phospholipid bilayer
D) attaching to the cytoskeleton
E) establishing the diffusion barrier to charged molecules

B

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.

B

An organism with a cell wall would most likely be unable to take in materials through
A) diffusion.
B) osmosis.
C) active transport.
D) phagocytosis.
E) facilitated diffusion.

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

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

B

ECM proteins are made by ribosomes in which part of a eukaryotic cell?

a) nuclear envelope

b) cytoplasm

c) mitochondria

d) golgi apparatus

e) rough ER

E

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

A

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

D

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

D

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.

D

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
A) by binding at the active site of the enzyme
B) by changing the shape of the enzyme's active site
C) by changing the free energy change of the reaction
D) by acting as a coenzyme for the reaction
E) by decreasing the activation energy of the reaction

B

Which of the following sequences correctly represents the flow of electrons during photosynthesis?
A) NADPH → O₂ → CO₂
B) H₂O → NADPH → Calvin cycle
C) NADPH → chlorophyll → Calvin cycle
D) H₂O → photosystem I → photosystem II
E) NADPH → electron transport chain → O₂

B

One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?
A) G protein-coupled receptors
B) ligand-gated ion channels
C) steroid receptors
D) receptor tyrosine kinases

D

Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.

What did Engelmann conclude about the congregation of bacteria in the red and blue areas?
A) Bacteria released excess carbon dioxide in these areas.
B) Bacteria congregated in these areas due to an increase in the temperature of the red and blue light.
C) Bacteria congregated in these areas because these areas had the most oxygen being released.
D) Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths.
E) Bacteria congregated in these areas due to an increase in the temperature caused by an increase in photosynthesis.

C

Starting with one molecule of glucose, the energy-containing products of glycolysis are _____.

A) 2 NAD+, 2 pyruvate, and 2 ATP

B) 2 NADH, 2 pyruvate, and 2 ATP

C) 2 FADH2, 2 pyruvate, and 4 ATP

D) 6 CO2, 2 pyruvate, and 2 ATP

B

What event accompanies energy absorption by chlorophyll (or other pigment molecules of the antenna complex)?

A) ATP is synthesized from the energy absorbed.

B) A carboxylation reaction of the Calvin cycle occurs.

C) Electrons are stripped from NADPH.

D) An electron is excited.

D

Adenylyl cyclase has the opposite effect of which of the following?
A) protein kinase
B) protein phosphatase
C) phosphodiesterase
D) phosphorylase
E) GTPase

C

Which of the following statements is a logical consequence of the second law of thermodynamics?
A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe.
B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe.
C) Every energy transfer requires activation energy from the environment.
D) Every chemical reaction must increase the total entropy of the universe.
E) Energy can be transferred or transformed, but it cannot be created or destroyed.

D

Scientists isolate cells in various phases of the cell cycle. They find a group of cells that have 1 1/2 times more DNA than G1 phase cells. The cells of this group are _____.

A) between the G1 and S phases in the cell cycle

B) in the G2 phase of the cell cycle

C) in the M phase of the cell cycle

D) in the S phase of the cell cycle

D

Which curve(s) on the graphs may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline hot springs at temperatures of 70°C or higher?
A) curves 1 and 5
B) curves 2 and 4
C) curves 2 and 5
D) curves 3 and 4
E) curves 3 and 5

E

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction?
A) -40 kcal/mol
B) -20 kcal/mol
C) 0 kcal/mol
D) +20 kcal/mol
E) +40 kcal/mol

B

This question is based on the reaction A + B ↔ C + D shown in the figure.

Which of the following terms best describes the forward reaction in Figure 8.1?
A) endergonic, ∆G > 0
B) exergonic, ∆G < 0
C) endergonic, ∆G < 0
D) exergonic, ∆G > 0
E) chemical equilibrium, ∆G = 0

B

During which phase of mitosis do the chromatids become chromosomes?

A) telophase
B) anaphase
C) prophase
D) metaphase
E) cytokinesis

B

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from _____.

A) water

B) glucose

C) air

D) electrons from NADPH

A

The primary role of oxygen in cellular respiration is to
A) yield energy in the form of ATP as it is passed down the respiratory chain.
B) act as an acceptor for electrons and hydrogen, forming water.
C) combine with carbon, forming CO₂.
D) combine with lactate, forming pyruvate.
E) catalyze the reactions of glycolysis

B

Which of the following types of signaling is represented in the figure?
A) autocrine
B) paracrine
C) hormonal
D) synaptic
E) long distance

D

In the figure, the dots in the space between the two structures represent which of the following?
A) receptor molecules
B) signal transducers
C) neurotransmitters
D) hormones
E) pheromones

C

In autotrophic bacteria, where is chlorophyll located?

A) in chloroplast membranes

B) in the ribosomes

C) in the nucleoid

D) in the infolded plasma membrane

D

In a plant, the reactions that produce molecular oxygen (O2) take place in _____.

A) the light reactions alone

B) the Calvin cycle alone

C) the light reactions and the Calvin cycle

D) neither the light reactions nor the Calvin cycle

A

One function of both alcohol fermentation and lactic acid fermentation is to _____.

A) reduce NAD+ to NADH

B) reduce FAD+ to FADH2

C) oxidize NADH to NAD+

D) reduce FADH2 to FAD+

C

The first gap in the cell cycle (G1) corresponds to _____.

A) normal growth and cell function

B) the phase in which DNA is being replicated

C) the beginning of mitosis

D) the phase between DNA replication and the M phase

A

When electrons move closer to a more electronegative atom, what happens?
A) The more electronegative atom is reduced, and energy is released.
B) The more electronegative atom is reduced, and energy is consumed.
C) The more electronegative atom is oxidized, and energy is consumed.
D) The more electronegative atom is oxidized, and energy is released.
E) The more electronegative atom is reduced, and entropy decreases.

A

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?
A) 0%
B) 2%
C) 10%
D) 38%
E) 100%

E

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
A) CO₂ and glucose
B) H₂O and O₂
C) ADP, Pi, and NADP⁺
D) electrons and H⁺
E) ATP and NADPH

E

In a plant cell, where are the ATP synthase complexes located?
A) thylakoid membrane only
B) plasma membrane only
C) inner mitochondrial membrane only
D) thylakoid membrane and inner mitochondrial membrane
E) thylakoid membrane and plasma membrane

D

If there are 20 duplicated chromosomes in a cell, how many centromeres are there?

A) 10

B) 20

C) 30

D) 40

B

Which of the following is an example of potential rather than kinetic energy?
A) the muscle contractions of a person mowing grass
B) water rushing over Niagara Falls
C) light flashes emitted by a firefly
D) a molecule of glucose
E) the flight of an insect foraging for food

D

Which of the following statements describes the results of this reaction?
C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + Energy
A) C₆H₁₂O₆ is oxidized and O₂ is reduced.
B) O₂ is oxidized and H₂O is reduced.
C) CO₂ is reduced and O₂ is oxidized.
D) C₆H₁₂O₆ is reduced and CO₂ is oxidized.
E) O₂ is reduced and CO₂ is oxidized.

A

In the figure, why does the reaction rate plateau at higher reactant concentrations?
A) Feedback inhibition by product occurs at high reactant concentrations.
B) Most enzyme molecules are occupied by substrate at high reactant concentrations.
C) The reaction nears equilibrium at high reactant concentrations.
D) The activation energy for the reaction increases with reactant concentration.
E) The rate of the reverse reaction increases with reactant concentration.

B

Metaphase is characterized by _____.

A) aligning of chromosomes on the equator

B) splitting of the centromeres

C) cytokinesis

D) separation of sister chromatids

A

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?
A) photosystem II
B) photosystem I
C) cyclic electron flow
D) linear electron flow
E) chlorophyll

C

If there are 30 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis?

A) 5
B) 10
C) 15
D) 30
E) 60

C

Substrate-level phosphorylation occurs _____.

A) in glycolysis

B) in the citric acid cycle

C) in both glycolysis and the citric acid cycle

D) during oxidative phosphorylation

C

Kinetochore microtubules assist in the process of splitting centromeres by _____.

A) using motor proteins to split the centromere at specific arginine residues

B) creating tension by pulling toward opposite poles

C) sliding past each other like actin filaments

D) phosphorylating the centromere, thereby changing its conformation

B

Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
A) the splitting of water
B) the absorption of light energy by chlorophyll
C) the flow of electrons from photosystem II to photosystem I
D) the synthesis of ATP
E) the reduction of NADP⁺

D

Which of the following occurs in the cytosol of a eukaryotic cell?
A) glycolysis and fermentation
B) fermentation and chemiosmosis
C) oxidation of pyruvate to acetyl CoA
D) citric acid cycle
E) oxidative phosphorylation

A