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?
the absorption of heat by the breaking of hydrogen bonds
the nucleus of a nitrogen atom contains 7 neutrons and 7 protons. which of the following is a correct statement concerning nitrogen?
the nitrogen atom has a mass number of 14 and an atomic mass of approx. 14 daltons
a localized group of organisms that belong to the same species is called a
population
prokaryotes are classified as belonging to two different domains. what are the domains?
bacteria and archaea
which of the following molecules contains the most polar covalent bond
h2o
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?
1
why does ice float in liquid water
hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
through time, the lineage that led to modern whales shows a change from four-limbed land animals to aquatic animals with two limbs that function as flippers. this change is best explained by
natural selection
organisms interact w/ their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight into
chemical energy
which brand of biology is concerned with the naming and classifying of organisms?
taxonomy
a slice of pizza has 500 kcal. if we could burn the pizza and use all the heat to warm a 5-L container a cold water, what would be the approx. increase in the temperature of the water? (Note: a liter of cold water weighs about 1Kg)
10 degrees C
knowing just the atomic mass of an element allows inferences about which of the following
the number of protons plus neutrons in the element.
the partial negative charge in a molecule of water occurs because
the electrons shared between the oxygen and hydrogen atoms spend more tie around the oxygen atom nucleus than around the hydrogen atom nucleus
what coefficients must be balanced in the following blanks so that all atoms are accounted for in the products?
C6H12O6 -> __ C2H6O + __CO2
2,2
which of the following statements is false?
virtually all organisms require the same elements in the same quantities
Hydrophobic substances such as vegetable oil are
nonpolar substances that repel water molecules
what is the max number of covalent bonds an element w/ atomic number of 8 can make w/ hydrogen
2
which of the following is a hydrophobic material?
butter
the application of scientific knowledge for some specific purpose is known as
technology
which of the following best describes he logic of scientific inquiry?
if my hypothesis is correct I can expect certain test results
in a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
polar covalent bonds
according to darwinian theory, which of the following exhibits the greatest fitness for evolutionary success?
the individuals within a population that have the greatest reproductive success
what is the hydrogen ion {H+} concentration of a solution of pH 8?
18-8 M
if the pH of a solution is increased from pH 5 to pH 7, it means that the
concentration of OH- is 100 times greater than what it was at pH 5
a dietary calorie equals 1 kilocalorie. which of the following statements correctly defines 1 kilocalorie
1000 calories or the amount of heat required to raise the temperature of 1 kg of water by 1 degree C
systems biology is mainly an attempt to
understand the behavior of entire biological systems
all the organisms on your campus make up
a community
in what way are elements in the same column of the periodic table the same
they have the same number of electrons in their valence shell
one difference between carbon -12 is that carbon - 14 has
two more neutrons than carbon-12
electrons exist only at fixed level of potential energy. however if an atom absorbs sufficient energy a possible result is that
the atom would become a negatively charged ion, or anion
why is each element unique and different from other elements in chemical properties
each element has a unique number of protons in its nucleus
one mole (mol) of glucose (molecular mass = 180 Daltons' ) is
both 180 grams of glucose and 6.02 x 10^23 molecules of glucose
which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH
gastric juice at pH 2
which of the following is an example of qualitative data
the spider spun its web in a circular motio
nitrogen (N) is much more electronegative than hydrogen (H). which of the following statements is correct about the atom in ammonia (NH3)
each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge
we can be sure that a mole of table sugar and a mole of vitamin v are equal in their
number of molecles
the main source of energy for producers in an ecosystem is
light energy
which type of bond must be broken for water to vaporize
hydrogen bond
what is the maximum number of electrons in a single 2 p orbital of an atom
2
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
hydrogen bond
which of the following explains most specifically the attraction of water molecules to one another.
hydrogen bond
when applying the process of science, which of these is tested?
prediction
a solution contains 0.000001 (10-7) moles of hydroxyl ions [OH-]per liter. which of the following best describes this solution?
neutral
an atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
it would form ions with a =2 charge
why is it important that an experiment include a control group?
without a control group, there is no basis for knowing if a particular result is due to the variable being tested
which statement is true of all atoms that are anion?
the atom has more electrons than protons
which of the following takes place as an ice cube cools a drink?
kinetic energy in the drink decreases
when two atoms are equally electronegative, they will interact to form
nonpolar covalent bonds
humans can digest starch but not cellulose because
humans have enzymes that can hydrolyze the a glycosidic linkages of starch but not the b glycosidic linkages of cellulose
research indicates that ibuprofen, a drug used to relieve inflammation nd pain, is a mixture of two enantiomers; that is, molecules that
are mirror images of one another
in animal metabolism, most of the monomers releases 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?
water is consumed by animal metabolism
the structural level of a protein LEAST affected by a disruption in hydrogen bonding is the
primary level
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. how is lactose classified?
as a disaccharide
which of the following categories includes all others in the list
carbohydrate
the element present in all organic molecules is
carbon
what is the structural feature that allows DNA to replicate
complementary pairing of the nitrogenous bases
the enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the a form. which of the following could amylase break down?
glycogen, starch, and amylopectin
which two functional groups are always found in amino acids?
carboxyl and amino
how many electron pairs does carbon share in order to complete its valence shell
4
at which level of protein structures are interactions between the side chains (R groups) most important?
tertiary
how many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
10
what is the term used for a protein molecule that assists in the proper folding of other proteins
chaperonin
on food packages, to what does the term insoluble fiber refer
cellulose
which of the following statements concerning unsaturated fats is true
they have double bonds in the carbon chains of their fatty acids
which of the following statements correctly describes cis-trans isomers?
they have variations in arrangement around a double bond
which of the following statements concerning saturated fats is not true
they have multiple double bonds in the carbon chains of their fatty acids
what is the chemical reaction mechanism by which cells make polymers from monomers
dehydration reactions
a carbon atom is most likely to form what kind of bond(s) with other atoms?
covalent
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?
the hydrogenated vegetable oil stays solid at room temperature
which of the following is not a polymer
glucose
there are 20 different amino acids. what makes one amino acid different from another?
different side chains (R groups) attached to an a carbon
which type of interaction stabilizes the a helix and the b pleated sheet structures of proteins
hydrogen bonds
which of the following are nitrogenous bases of the pyrimidine type
cytosine and uracil
which of these molecules is not formed by dehydration reactions
fatty acids
if one strand of DNA molecule has the sequence of bases 5'ATTGCA3' the other complementary strand would have the sequence
5'TGCAAT3'
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 steroid
when biologists wish to study the internal ultrastructure of cells they most likely would use
a transmission electronic microscope
plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells
gap junction
a newspaper ad for a local toy store indicates that a very inexpensive microscope available for a small child is able to magnify secimens nearly as much as the much more costly microscope available in your college lab. what is the primary reason for the price difference
the toy microscope magnifies a good deal, but has low resolution and therefore poor quality images
all of the following are part of a prokaryotic cell except
an endoplasmic reticulum
large numbers of ribosomes are present in cells that specialize in producing which of the following molecules
proteins
which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids?
smooth endoplasmic reticulum
which structure is the site of the synthesis of proteins that may be exported from the cell
rough er
which statement correctly characterizes bound ribosomes?
bound ribosomes generally synthesize membrane proteins and secretory proteins
in animal cells, hydrolytic enzymes are packages to prevent general destruction of cellular components. which of the following organelles functions in this compartmentalization
peroxisome
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?
smooth er
which of the following is a compartment that often takes up much of the volume of a plant cell
central vacuole
which of the following factors would tend to increase membrane fluidity
a greater proportions of unsaturated phospholipids
grana, thylakoids, and stroma are all components found in
chloroplasts
organelles other than the nucleus that contain DNA include
mitochondria and chloroplasts
which of the following are capable of converting light energy to chemical energy
chloroplasts
a primary objective of cell fractionation is to
crack the cell wall so the cytoplasmic contents can be released
in what way do the membranes of a eukaryotic cell vary?
certain proteins are unique to each membrane
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, while organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively,
chloroplasts and mitochondria
which of the following is a major cause of the size limits for certain types of cells
the need for a surface area of sufficient area to allow the cell's function
which of the following processes includes all others
passive transport
cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide would be found within the
mitochondria
which cell would be best for studying lysosomes
phagocytic white blood cell
which of the following types of molecules are the major structural components of the cell membrane
phospholipids and protins
the presence of cholesterol in the plasma membranes of some animals
enables the membrane to stay fluid more easily when cell temperature drops
according to the fluid mosaic model of membrane structure, proteins of the membrane are mostly
embedded in a lipid bilayer
according to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids
they can easily move laterally along the plane of the membrane
in order for a protein to be an integral membrane protein (an integrin) it would have to be which of the following
amphipathic
which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
the double bonds form kinks in the fatty acid tails, forcing adjacent lipids to be further apart
which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cell
the animal cell s in an isotonic solution and the plant cell is in a hypotonic solution
of the following functions which is most important for the glycoproteins and glycolipids of animal cell membranes
a cell's ability to distinguish one type of neighboring cell from another
why are lipids and proteins free to move laterally in membranes?
hydrophilic portions of the lipids are in the interior of the membrane
the Golgi apparatus has a polarity or sidedness to its structure and function. which the following statements correctly describes this polarity?
all of the above correctly describe polar characteristics of the Golgi function
which of the following statements is correct about diffusion
it is a passive process in which molecules move from a region of higher concentration to a region of lower concentration
what is the voltage across a membrane called?
membrane potential
water passes quickly through cell membranes because
it moves through aquaporins in the membrane
a patient has had a serious accident and lost a lot of blood. in an attempt to replenish body fluids, distilled water, equal to the volume of blood lost, is transferred directly into one of his veins. what will be the most probable result of this transfusion?
the patients red blood cells will swell because the blood fluid is hypotonic compared to the cells
a cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. assuming that glucose is not actively transported into the cell, which of the follow terms describes the tonicity of the external solution relative to the cytoplasm of the cell
isotonic
which of the following membrane activities require energy from ATP hydrolysis?
Na+ ions moving out of the cell
which is one of the main energy transformers of cells
mitochondrion
white blood cells engulf bacteria through what process
phagocytosis
which term most precisely describes the cellular process of breaking down large molecules into smaller ones
catabolism
which of the following is a statement of the first law of thermodynamics?
energy cannot be created or destroyed
whenever energy is transformed, there is always an increase in the
entropy of the universe
which of the following is an example of potential rather than kinetic energy
a molecule of glucose
which of the following is the smallest closed system
a thermos
which of the following is true of metabolism in its entirety in all organisms
metabolism consists of all the chemical reactions in an organism
the mathematical expression for the change in free energy of a system is ▲G = ▲H - T▲S. which of the following is (are) correct?
▲G is the change in free energy
a system at chemical equilibrium
can do no work
which of the following is true for all exergonic reactions
the reaction proceeds with a net release of free energy
reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reactions
activation energy
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?
-20 kcal/mol
how does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
by changing the shape of the enzyme's active site
some bacteria are metabolically active in hot springs because
their enzymes have high optimal temperatures
chose the pair of terms that correctly completes this sentence:
Catabolism is to anabolism as _____ is to ______
exergonic;endergonic
most cells cannot harness heat to perform work because
temperature is usually uniform throughout a cell
in an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?
nothing, the reaction will stay at equilibrium
when a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes
oxidized
the molecule that functions as the reducing agent (electron donor) in a redox or oxidation - reduction reaction
loses electrons and loses potential energy
which process in eukaryotic cells will proceed normally whether oxygen (o2) is present or absent?
glycolysis
why is glycolysis described as having an investment phase and a payoff phase
it uses stored atp and them forms a net increase in ATP
which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate?
acetyl CoA
how many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate
two
where are the proteins of the electron transport chain locatd
mitochondrial inner membrane
the immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the
H+ concentration across the membrane holding ATP synthase
what is the oxidizing agent in the following reaction?
Pyruvate + NADH + H+ -> Lactate + NAD+
pyruvate
most CO2 from catabolism is released during
the citric acid cycle