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exam two multiple choice

Terms in this set (32)

which of the following descriptions best fits the class of molecules known as nucleotides?

a. a nitrogenous base, a phosphate group, and a sugar
b. a nitrogenous base and a sugar
c. a sugar and a purine or pyrimidine
d. a nitrogenous base and a phosphate group
a nitrogenous base, a phosphate group, and a sugar
cyanide blocks the transport of electrons to oxygen. cyanide is most likely inhibiting ____________.

a. electron transport chain
b. fermentation
c. citric acid cycle
d. glycolysis
e. pyruvate oxidation
electron transport chain
what is the name of the thermodynamic barrier that must be overcome before products are formed in a spontaneous reaction?

a. the equilibrium point
b. free energy
c. entropy
d. activation energy
activation energy
which of the following processes is not like the others?

a. transport of an ion against its electrochemical gradient
b. active transport
c. phagocytosis
d. facilitated diffusion
facilitated diffusion
which of the following is true about the citric acid cycle (aka kreb's cycle)?

a. it does not release/generate any CO2
b. it requires acetyl CoA as an input
c. it generates the most ATP among all respiration processes
d. it directly requires oxygen
it requires acetyl CoA as an input
which of the summary statements below describes the results of the following reaction?
C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + energy

a. O2 is oxidized and H2O is reduced
b. O2 is reduced and CO2 is oxidized
c. C6H12O6 is oxidized and O2 is reduced
d. CO2 is reduced and O2 is oxidized
C6H12O6 is oxidized and O2 is reduced
which of the following would likely diffuse through the lipid bilayer of a plasma membrane most rapidly?

a. an amino acid
b. O2
c. sucrose
d. Na+
O2
which of the following is a storage polysaccharide that is frequently used by humans?

a. glycogen
b. chitin
c. starch
d. glucose
glycogen
which of the following is an example of potential rather than kinetic energy?

a. a molecule of glucose
b. water rushing over niagara falls
c. light flashes emitted by a firefly
d. a crawling beetle foraging for food
a molecule of glucose
which of the following statements is a reasonable explanation of why unsaturated fatty acids help keep a membrane more fluid?

a. unsaturated fatty acids are more nonpolar than saturated fatty acids
b. the double bonds block interaction among the hydrophilic heads of the lipids
c. they don't, saturated fatty acids keep the membrane more fluid because of their compact structure
d. the double bonds form kinks in the fatty acid chain, preventing adjacent lipids from packing tightly
the double bonds form kinks in the fatty acid chain, preventing adjacent lipids from packing tightly
which of the following metabolic processes can occur with no net input of energy from some other process?

a. C6H12O6 + 6O2 --> 6CO2 + 6H2O
b. ADP + P --> ATP + H2O
c. amino acids --> protein
d. 6CO2 + 6H2O --> C6H12O6 + 6O2
C6H12O6 + 6O2 --> 6CO2 + 6H2O
the break down of macromolecules requires of series of ___________ reactions that break _____________ bonds between monomers.

a. dehydration; covalent
b. hydrophilic; ionic
c. denaturation; ionic
d. hydrolysis; covalent
hydrolysis; covalent
which of the following metabolic processes normally occurs regardless of whether or not oxygen (O2) is present?

a. oxidative phosphorylation
b. citric acid cycle
c. lactate fermentation
d. glycolysis
glycolysis
following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. most of the energy from the original glucose molecule at that point in the process, however, is stored in the form of which of the following molecules?

a. NAD+
b. pyruvate
c. NADH
d. acetyl-CoA
NADH
why is it beneficial for ions to move down their concentration gradient after cells expend energy to create this gradient?

a. there is energy in the gradients that can be transferred and used for cellular work
b. it isn't beneficial but ions can diffuse through the membrane without interference
c. it isn't beneficial as all cellular work is done by using ATP as the energy source
d. cells allow ions to leak out of cells in order to decrease the tonicity of their environment
there is energy in the gradients that can be transferred ad used for cellular work
oxidative phosphorylation is the final part of cellular respiration. list the following steps of oxidative phosphorylation in sequential order (first to last according to the steps provided below).
I. H+ ions flow down a gradient to generate ATP by the enzyme, ATP synthase
II. electrons are transferred from the citric acid cycle into the electron transport chain
III. electrons are transferred to oxygen, causing it to split and take up H+ ions, which forms water
IV. H+ ions are pumped across the mitochondrial membrane to establish an electrochemical gradient

a. I, IV, III, II
b. II, III, I, IV
c. IV, III, II, I
d. I, II, III, IVe. II, IV, III, I
II, IV, III, I
a disruption in hydrogen bonding due to an increase in temperature has occurred in your favorite protein, which level of structure would likely be least affected?

a. primary level
b. secondary level
c. tertiary level
d. quaternary level
primary level
which of the following is a major difference between RNA and DNA?

a. type of glycosidic bond
b. type of purines
c. type of phosphate
d. type of sugar
type of sugar
which of the following statements is a logical consequence of the second law of thermodynamics?

a. 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
b. if the entropy of a system decreases, there must be a corresponding decrease in the entropy of the universe
c. each chemical reaction in an organism must increase the total entropy of the universe
d. if the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe
each chemical reaction in an organism must increase the total entropy of the universe
the force driving simple diffusion is ____________, while the energy source for active transport is ______________.

a. a concentration gradient; ADP
b. a concentration gradient; ATP hydrolysis
c. transmembrane pumps; an electrochemical gradient
d. phosphorylated carrier proteins; ATP
a concentration gradient; ATP hydrolysis
humans can digest starch but not cellulose because __________.

a. starch is digested by microorganisms in the colon but cellulose is not
b. the monomer of starch is glucose, while the monomer of cellulose is galactose
c. starch monomers are joined by covalent bonds, and cellulose monomers are joined by ionic bonds
d. humans have enzymes that can hydrolyze the a-glycosidic linkages of starch but not the b-glycosidic linkages of cellulose
humans have enzymes that can hydrolyze the a-glycosidic linkages of starch but not the b-glycosidic linkages of cellulose
why is it that denaturation makes proteins function poorly or not at all?

a. proteins are broken down partially or completely into their monomers by denaturation, and the monomers are not as effective for function
b. denaturation adds nonpolar groups that change the solubility of certain proteins
c. protein function depends on constant naturation provided by the DNA, and denaturation removes that protection
d. denaturation removes critical amino acids that determine protein functions
e. protein function depends on shape, and denaturation damages protein shape
protein function depends on shape, and denaturation damages protein shape
which of the following sequences describes the path by which electrons travel downhill energetically in aerobic respiration?

a. food, glycolysis, citric acid cycle, NADH, ATP
b. glucose, NADH, electron transport chain, oxygen
c. glucose, pyruvate, electron transport chain, NADH, ATP
d. glucose, pyruvate, ATP, oxygen
glucose, NADH, electron transport chain, oxygen
select the correct match of transport across a plasma membrane and description.

a. exocytosis--creates vesicles to transport bulk amounts of liquids into the cell
b. facilitated diffusion--movement down concentration gradient through a specific transport protein (no energy required)
c. pinocytosis--expels undigested food particles out of the cell
d. osmosis--movement of any type of substance along its concentration gradient
facilitated diffusion--movement down concentration gradient through a specific transport protein (no energy required)
in which reactions of cellular respiration does substrate level phosphorylation occur?

a. only in glycolysis
b. only in the electron transport chain
c. only in the citric acid cycle
d. in both glycolysis and the citric acid cycle
in both glycolysis and the citric acid cycle
pick the metabolic process that is exergonic.

a. going from a polypeptide to amino acids
b. going from CO2 to glucose
c. going from nucleotides to DNA
d. going from glucose to chitin
e. going from a polypeptide to a protein
going from a polypeptide to amino acids
which amphipathic lipid is the most prevalent in the plasma membrane?

a. waxes
b. transmembrane proteins
c. phospholipids
d. glycolipids
phospholipids
a chemical reaction that has a negative ^G is best described as ___________ and is a ___________ reaction.

a. endergonic; spontaneous
b. exergonic; spontaneous
c. enthalpic; nonspontaneous
d. entropic; nonspontaneous
exergonic; spontaneous
the first molecules of CO2 from catabolism are released during _____________.

a. the citric acid cycle
b. electron transport
c. pyruvate oxidation
d. lactate fermentation
pyruvate oxidation
the membranes of an animal cell are able to remain fluid when it is extremely cold by _____________.

a. increasing the percentage of cholesterol molecules in the membrane
b. decreasing the number of hydrophobic proteins in the membrane
c. increasing the proportion of glycolipids in the membrane
d. decreasing the proportion of unsaturated phospholipids in the membrane
increasing the percentage of cholesterol molecules in the membrane
the enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis. PFK is inhibited by high levels of which of the following molecules?

a. ATP and citrate
b. citrate and CO2
c. AMP and ADP
d. glucose and NAD+
ATP and citrate
what will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?

a. the cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC
b. the cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC
c. the cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC
d. the cell will remain the same size because the solution outside the cell is isotonic
the cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC
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