Chapter 5

How many ATP molecules can be produced from the NADH generated by the catabolism of a molecule of glucose? 34 4 30 38 36

30

Which of the following is a TRUE statement concerning the structure and function of enzymes? An apoenzyme is a combination of a cofactor bound to a holoenzyme. All enzymes bind to cofactors necessary for their function. After an enzyme has catalyzed a reaction, it resumes its original shape and can interact with a new substrate molecule. Competitive inhibition of an enzyme occurs when an inhibitor binds to an allosteric site on the enzyme. The higher the temperature, the faster an enzyme will work.

After an enzyme has catalyzed a reaction, it resumes its original shape and can interact with a new substrate molecule.

Which of the following statements concerning reduction reactions is FALSE? They frequently involve electron carrier molecules. An electron acceptor becomes more positively charged. An electron acceptor gains an electron. They are coupled with oxidation reactions. A molecule gains a hydrogen atom.

An electron acceptor becomes more positively charged.

Ribozymes are enzymes that cleave the subunits of the ribosome. True False

False

Which of the following statements concerning glycolysis is TRUE? It produces ATP by oxidative phosphorylation. It both requires the input of ATP and produces ATP. It is an alternative to fermentation. It occurs in the cell membranes of bacteria. It involves ribulose 5-phosphate as an intermediate.

It both requires the input of ATP and produces ATP.

Which of the following statements concerning cellular metabolism is FALSE? Energy obtained from nutrients or light is stored in the bonds of ATP. The goal of metabolism is reproduction of the organism. ATP is used in the formation of macromolecules. Macromolecules are converted into cell structures via catabolism. Enzymes are used in both catabolic and anabolic reactions.

Macromolecules are converted into cell structures via catabolism.

Which of the following is associated with the Calvin-Benson cycle? RuBP acetyl-CoA TMAO FADH2 PABA

RuBP

Which of the following statements concerning enzymes is FALSE? They can be used to catalyze a chemical reaction over and over again. They are usually, but not always, proteins. They function best at 37°C. They form a temporary intermediate compound with a substrate. They can be denatured if the pH of their environment is too high or too low.

They function best at 37°C.

Environmental changes can result in the inactivation of enzymes. True False

True

Essential amino acids are amino acids that cannot be synthesized by an organism and so must be provided as nutrients. True False

True

Fermentation pathways provide a cell with an alternative way to regenerate NAD+ for glycolysis. True False

True

Reactions that are both catabolic and anabolic are amphibolic. True False

True

Which of the following statements concerning the Krebs cycle is FALSE? Two molecules of acetyl-CoA generate more ATP after two cycles than a single molecule of glucose at the end of glycolysis. The ATP generated is initially GTP. NAD+ and FAD are reduced as a result. It is also known as the tricarboxylic acid cycle. Oxaloacetic acid is regenerated.

Two molecules of acetyl-CoA generate more ATP after two cycles than a single molecule of glucose at the end of glycolysis.

When a cell forms an amino acid by adding an amine group derived from ammonia to a precursor metabolite, this process is called reduction. deamination. polymerization. transamination. amination.

amination.

Which of the following is a by-product of the catabolism of proteins? lactic acid carbon dioxide ammonia proteases acetyl-CoA

ammonia

Chemical reactions that can proceed toward either anabolism or catabolism are called cyclic. light-independent. synthetic. glycolytic. amphibolic.

amphibolic.

Reactions involving ligases are typically __________ reactions. anabolic catabolic both anabolic and catabolic neither anabolic nor catabolic exergonic

anabolic

Reactions catalyzed by transferases are anabolic. catabolic. neither anabolic nor catabolic. both anabolic and catabolic. reactions that do not require cofactors.

anabolic.

All of the following are associated with chemiosmosis EXCEPT phosphorylation of 34 molecules of ADP. ATP synthase. creation of a proton gradient. beta-oxidation. oxidative phosphorylation.

beta-oxidation.

Oxidoreductases participate in __________ reactions. anabolic catabolic both anabolic and catabolic neither anabolic nor catabolic energy neutral

both anabolic and catabolic

Which of the following is (are) common to chemiosmosis and the light-dependent reactions of photosynthesis? a proton gradient reduction of NADP+ electron transport both electron transport and a proton gradient electron transport, a proton gradient, and reduction of NADP+

both electron transport and a proton gradient

Substrate-level phosphorylation occurs during the __________ stage(s) of glycolysis. lysis energy-investment energy-conservation both energy-investment and energy-conservation energy-investment, lysis, and energy-conservation

both energy-investment and energy-conservation

Pyruvic acid is a product of the Krebs cycle. glycolysis. the Entner-Doudoroff pathway. fermentation. both glycolysis and the Entner-Doudoroff pathway.

both glycolysis and the Entner-Doudoroff pathway.

Which of the following can be the final electron receptor in anaerobic respiration in bacteria? sulfate pyruvic acid nitrate both nitrate and sulfate both pyruvic acid and sulfate

both nitrate and sulfate

Which of the following produces NADPH? the Embden-Meyerhof pathway the pentose phosphate pathway the Entner-Doudoroff pathway both the Embden-Meyerhof and Entner-Doudoroff pathways both the pentose phosphate and Entner-Doudoroff pathways

both the pentose phosphate and Entner-Doudoroff pathways

Enzymes known as lyases participate in __________ reactions. catabolic anabolic both anabolic and catabolic neither anabolic nor catabolic oxidation-reduction

catabolic

Hydrolases are generally involved in __________ reactions. catabolic anabolic both anabolic and catabolic neither anabolic nor catabolic oxidation-reduction

catabolic

Sulfanilamide is an antimicrobial drug that mimics the shape of an important substrate for a particular bacterial enzyme, thereby inhibiting the enzyme. This type of inhibition is known as competitive inhibition. feedback inhibition. allosteric inhibition. noncompetitive inhibition. excitatory allosteric control.

competitive inhibition.

The conversion of pyruvic acid to acetyl-CoA can be described as __________, because a molecule of CO2 is produced as a by-product. phosphorylation decarboxylation amination respiration oxidation

decarboxylation

The production of NADH takes place during the __________ stage(s) of glycolysis. lysis energy-investment energy-conservation both lysis and energy-investment both energy-investment and energy-conservation

energy-conservation

In which of the following stages of glycolysis is ATP made? lysis stage energy-investment stage energy-conserving stage both the energy-investment and the lysis stages both the lysis and energy-conserving stages

energy-conserving stage

Glucose enters glycolysis at the __________ stage(s). energy-investment lysis energy-conservation both lysis and energy-conservation both energy-investment and conservation

energy-investment

Although glycolysis requires an input of ATP, this pathway results in a net gain of two ATP; therefore it is a(n) __________ pathway. reductive neither exergonic nor endergonic endergonic oxidative exergonic

exergonic

If a cell reverses the process of beta-oxidation, which of the following molecules will it make? glycerol nucleotides fatty acids starch amino acids

fatty acids

Anabolic reactions may be characterized as producing ATP. breaking large molecules into smaller molecules to produce ATP. breaking large molecules into smaller molecules. forming large molecules from smaller molecules. exergonic.

forming large molecules from smaller molecules.

The conversion of amino acids to carbohydrates is an example of beta-oxidation. electron transport. gluconeogenesis. amination. substrate-level phosphorylation.

gluconeogenesis.

What is the major product of the Calvin-Benson cycle that can then be used to form glucose? NADPH CO2 RuBP ATP glyceraldehyde 3-phosphate

glyceraldehyde 3-phosphate

Which of the following types of carrier molecules is NOT found in electron transport chains? cytochromes hemoglobin ubiquinones metal-containing proteins flavoproteins

hemoglobin

Where is the most ATP generated for most eukaryotic cells? in the cytosol in the cytoplasmic membrane on ribosomes in the outer membrane of the mitochondria in the mitochondrial matrix

in the mitochondrial matrix

The intermediate known as DHAP is formed during the __________ stage(s) of glycolysis. lysis energy-investment energy-conservation both energy-investment and energy-conservation both lysis and energy-conservation

lysis

Reactions involving isomerases are anabolic. catabolic. both anabolic and catabolic. neither anabolic nor catabolic. exergonic.

neither anabolic nor catabolic.

What is the purpose of the light-dependent reactions of photosynthesis? production of ATP and NADH regeneration of NAD+ production of oxygen carbon fixation production of ATP and NADPH

production of ATP and NADPH

All of the following are forms of oxidation EXCEPT loss of hydrogen atom. loss of an electron. gain of an oxygen atom and its electrons. a dehydrogenation event. substrate level phosphorylation.

substrate level phosphorylation.

The molecule that an enzyme acts upon is known as its coenzyme. holoenzyme. catalyst. apoenzyme. substrate.

substrate.

Carbon dioxide is a by-product of which of the following? glycolysis chemiosmosis electron transport the pentose phosphate pathway the Krebs cycle

the Krebs cycle

Beta-oxidation of fatty acids produces a substrate of the Entner-Doudoroff pathway. the Embden-Meyerhof pathway. the Krebs cycle. the Calvin-Benson cycle. the pentose phosphate pathway.

the Krebs cycle.

Membranes containing the photosystems necessary for photosynthesis are called thylakoids. grana. chlorophylls. cytochromes. stroma.

thylakoids.

The metabolic processes called fermentation produce substrates for the Krebs cycle. use an organic molecule as a final electron acceptor. are alternatives for the pentose phosphate pathway. occur only when oxygen is readily available. produce substrates for glycolysis.

use an organic molecule as a final electron acceptor.

All of the following are aspects of a cell's ability to regulate its metabolism EXCEPT use of the most energy-efficient energy source available. synthesis of a catabolic enzyme only when its substrate is available. synthesis or degradation of membrane transport proteins. isolation of various enzymes within membranous organelles. use of the same coenzymes for anabolic and catabolic reactions that share substrate molecules.

use of the same coenzymes for anabolic and catabolic reactions that share substrate molecules.

Types of chlorophyll differ in the amount of oxygen they utilize. wavelengths of light they absorb. amount of ATP they produce. number of electrons they release. amount of light they can absorb.

wavelengths of light they absorb.