Chapter 5 Practice Questions

Which of the following compounds is NOT an enzyme?

a) cellulase

b) Beta-galactosidase

c) coenzyme A

d) sucrase

e) dehydrogenase

Which organism is NOT correctly matched to its energy source?

A) chemoautotroph-NH³

B) chemoautotroph - Fe²⁺

C) photoautotroph - CO₂

D) photoheterotroph - light

E) chemoheterotroph - glucose

Which of the following statements about anaerobic respiration is FALSE?

A) It involves the reduction of an organic final electron acceptor.

B) The complete Kreb's cycle is utilized.

C) It yields lower amounts of ATP when compared to aerobic respiration.

D) It generates ATP.

E) It requires cytochromes.

What is the fate of pyruvic acid in an organism that uses aerobic respiration?

A) It is reduced to lactic acid.

B) It reacts with oxaloacetate to form citrate.

C) It is converted into acetyl CoA.

D) It is catabolized in glycolysis.

E) It is oxidized in the electron transport chain.

Fatty acids are oxidized in

A) glycolysis.

B) the Entner-Doudoroff pathway.

C) the electron transport chain.

D) the pentose phosphate pathway.

E) the Krebs cycle.

Which of the following is the best definition of oxidative phosphorylation?

A) Electrons are passed through a series of carriers to an organic compound.

B) A proton gradient allows hydrogen ions to flow back into the cells through transmembraneprotein channels, releasing energy that is used to generate ATP.

C) Electrons are passed through a series of carriers to O2.

D) ATP is directly transferred from a substrate to ADP.

Which of the following statements about substrate-level phosphorylation is FALSE?

A) It occurs in glycolysis.

B) The oxidation of intermediate metabolic compounds releases energy that is used to generateATP.

C) It involves the direct transfer of a high-energy phosphate group from an intermediate metabolic compound to ADP.

D) No final electron acceptor is required.

E) It occurs in the Krebs cycle.

Which of the following statements about photophosphorylation is FALSE?

A) Light liberates an electron from chlorophyll.

B) It requires CO₂.

C) Energy from oxidation reactions is used to generate ATP from ADP.

D) Oxidation of carrier molecules releases energy.

E) It occurs in photosynthesizing cells.

A strictly fermentative bacterium produces energy

A) only in the absence of oxygen.

B) by fermentation or aerobic respiration.

C) by aerobic respiration only.

D) by glycolysis only.

E) only in the presence of oxygen.

The advantage of the pentose phosphate pathway is that it produces all of the following EXCEPT

A) precursors for the synthesis of amino acids.B) NADPH.

C) precursors for nucleic acids.

D) precursors for the synthesis of glucose.

E) three ATP's.

Which of the following statements about beta oxidation is FALSE?

A) It is a method of catabolizing fatty acids.

B) It involves the formation of acetyl-CoA.

C) It involves the formation of 2-carbon units.

D) It is a step in glycolysis.

E) It is used in petroleum degradation.

In noncyclic photophosphorylation, O2 is released from

A) C₆H₁₂O₆

B) chlorophyll.

C) sunlight.

D) H₂O

E) CO₂.

Which of the following is the best definition of fermentation?

A)complete catabolism of glucose to CO₂ and H₂O

B) the partial reduction of glucose to pyruvic acidC) the partial oxidation of glucose with organic molecules serving as electron acceptors

D) the production of energy by both substrate and oxidative phosphorylation

E) production of energy by oxidative-level phosphorylation

Which of the following is NOT necessary for respiration?

A) a source of electrons

B) cytochromes

C) quinones

D) flavoproteins

E) oxygen

Which one of the following would you predict is an allosteric inhibitor of the Krebs cycle enzyme,alpha-ketoglutarate dehydrogenase?

A) NADH

B) alpha-ketoglutaric acid

C) citric acid

D) NAD+

E) ADP

In green and purple bacteria, electrons to reduce CO₂ can come from

A) H₂O

B) chlorophyll.

C) CO₂.

D) H₂S.

E) C₆H₁₂O₆.

Assume you are growing bacteria on a lipid medium that started at pH 7. The action of bacteriallipases should cause the pH of the medium to

A) increase.

B) stay the same.

C) decrease.

Which of the following uses CO₂ for carbon and H₂ for energy?

A) photoautotroph

B) photoheterotroph

C) chemoheterotroph

D) chemoautotroph

Which of the following uses glucose for carbon and energy?

A) chemoheterotroph

B) photoautotroph

C) photoheterotroph

D) chemoautotroph

Which of the following has bacteriochlorophylls and uses alcohols for carbon?

A) photoautotroph

B) photoheterotroph

C) chemoheterotroph

D) chemoautotroph

Cyanobacteria are a type of

A) chemoheterotroph.

B) photoautotroph.

C) chemoautotroph.

D) photoheterotroph.

Which of the following statements are true?

1-Electron carriers are located at ribosomes.

2-ATP is a common intermediate between catabolic and anabolic pathways.

3-ATP is used for the long-term storage of energy and so is often found in storage granules.

4-Anaerobic organisms are capable of generating ATP via respiration.

5-ATP can be generated by the flow of protons across protein channels.

Microorganisms that catabolize sugars into ethanol and hydrogen gas would be categorized as

A) alcohol fermenters.

B) anaerobic respirers.

C) aerobic respirers.

D) homolactic fermenters.

E) heterolactic fermenters.

Which of the following statements regarding metabolism is FALSE?

A) Anabolic reactions are degradative.

B) Heat may be released in both anabolic and catabolic reactions.

C) ATP is formed in catabolic reactions.

D) ADP is formed in anabolic reactions.

Which of the following statements regarding the Entner-Doudoroff pathway is TRUE?

A) It involves the pentose phosphate pathway.

B) NADH is generated.

C) ATP is generated.

D) It involves glycolysis.

E) NADH and ATP are generated.

An enzyme, citrate synthase, in the Krebs cycle is inhibited by ATP. This is an example of all of thefollowing EXCEPT

A) allosteric inhibition.

B) feedback inhibition.

C) competitive inhibition

D) noncompetitive inhibition

If a cell is starved for ATP, which of the following pathways would most likely be shut down?

A) glycolysis

B) Kreb's cycle

C) pentose phosphate pathway

D) Krebs cycle and glycolysis

Which of the following statements regarding the glycolysis pathway is FALSE?

A) Two molecules of water are generated.

B) Two pyruvate molecules are generated.

C) Two NADH molecules are generated.

D) Four ATP molecules are generated via substrate-level phosphorylation.

E) One molecule of ATP is expended.

A bacterial culture grown in a glucose-peptide medium causes the pH to increase.The bacteria aremost likely

A) not growing.

B) fermenting the glucose.

C) using the peptides.

D) oxidizing the glucose.

Gallionella bacteria can get energy from the reaction Fe²⁺ → Fe³⁺. This reaction is an example ofA) the Calvin-Benson cycle.

B) reduction.

C) oxidation.

D) fermentation.

E) photophosphorylation.

Catabolic reactions are generally degradative and hydrolytic.

The pentose phosphate pathway can be characterized as an anabolic pathway.

In general, ATP is generated in catabolic pathways and expended in anabolic pathways.

An apoenzyme that loses its coenzyme subunit will be non-functional.

The use of enzymes is necessary to increase the activation energy requirements of a chemical reaction.

Glycolysis is utilized by cells in both respiration and fermentation.

Carbon fixation occurs during the light-independent phase of photosynthesis.

Both respiration and photosynthesis require the use of an electron transport chain.

Both respiration and photosynthesis use water molecules for the donation of hydrogen ions.

Once an enzyme has converted substrates into products, the active site reverts back to its originalform.

How many molecules of ATP can be generated from the complete oxidation of glucose to CO 2 and H2O?

A) 2

B) 4

C) 34

D) 38

E) 76

Which of the following is not true about anaerobic respiration?

A) It involves glycolysis only.

B) It involves the Krebs cycle.

C) It involves the reduction of nitrate.

D) It generates ATP.

E) It requires cytochromes.

According to the chemiosmotic mechanism, ATP is generated when

A) Electrons are transferred between carrier molecules.

B) A high-energy phosphate group is transferred from an intermediate metabolite to ADP.

C) Chlorophyll liberates an electron.

D) Protons are moved across a membrane.

E) Cells lyse in a hypotonic environment.

Which of the following is not an end-product of fermentation?

A) Lactic acid

B) Ethyl alcohol

C) Glycerol

D) Pyruvic acid

E) Acetone

What percent of the total ATP produced from the complete catabolism of glucose is producedby aerobic respiration?

A) 5%

B) 11%

C) 50%

D) 89%

E) 95%

Aerobic respiration differs from anaerobic respiration in which of the following respects?

A) Anaerobic respiration is glycolysis.

B) The final electron acceptors are different.

C) Aerobic respiration requires the electron transport chain.

D) Aerobic respiration gets electrons from the Krebs cycle.

E) Aerobic respiration produces more ATP.

Assume you are working for a chemical company and you are responsible for growing a yeastculture that produces ethyl alcohol. The yeasts are growing well on the maltose medium butare not producing alcohol. The most likely explanation is

A) The maltose is toxic.

B) O2 is in the medium.

C) Not enough protein is provided.

D) Yeasts donʹt produce ethyl alcohol.

E) None of the above.

A shipping company employee notices that the inside of shipsʹ hulls where ballast water is stored are deteriorating. The hull paint contained cyanide to prevent microbial growth. Since bacteria were growing on the hulls, you can conclude that the

A) Bacteria were using aerobic respiration.

B) Bacteria were using anaerobic respiration.

C) Bacteria were growing by fermentation.

D) Bacteria were using cytochromes.

E) None of the above.

When oxygen is unavailable, Halobacterium produce ATP by

A) Fermentation.

B) Photophosphorylation.

C) Oxidative phosphorylation.

D) Substrate-level phosphorylation.

E) The Krebs cycle.