Deck 5: Microbial Metabolism

Question 1

The molecule that an enzyme acts upon is known as its

A) substrate.
B) coenzyme.
C) apoenzyme.
D) product.
E) catalyst.

Answer 1

A

Question 2

An organic compound gains an electron from another molecule. The organic compound

A) has been oxidized.
B) is an electron donor.
C) has been reduced.
D) has become more positively charged.
E) has lost a hydrogen atom.

Answer 2

C

Question 3

How many ATP molecules can theoretically be produced from the NADH generated by the catabolism of a molecule of glucose during aerobic respiration?

A) 34
B) 30
C) 38
D) 36
E) 4

Answer 3

B

Question 4

Which of the following is a by-product of the catabolism of proteins?

A) lactic acid
B) acetyl-CoA
C) proteases
D) ammonia
E) carbon dioxide

Question 5

Which of the following is/are common to chemiosmosis and the light-dependent reactions of photosynthesis?

A) reduction of NADP⁺ only
B) electron transport only
C) a proton gradient only
D) both electron transport and a proton gradient
E) electron transport, a proton gradient, and reduction of NADP⁺

Question 6

Anabolic reactions may be characterized as

A) exergonic.
B) breaking large molecules into smaller molecules.
C) forming large molecules from smaller molecules.
D) producing ATP.
E) breaking large molecules into smaller molecules to produce ATP.

Question 7

Which of the following statements concerning enzymes is FALSE?

A) They are usually, but not always, proteins.
B) They always function best at 37°C.
C) They can be denatured if the pH of their environment is too high or too low.
D) They form a temporary intermediate compound with a substrate.
E) They can be used to catalyze a chemical reaction over and over again.

Question 8

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

A) allosteric inhibition.
B) competitive inhibition.
C) allosteric activation.
D) noncompetitive inhibition.
E) feedback inhibition.

Question 9

Which of the following produces NADPH?

A) the pentose phosphate pathway only
B) the Calvin-Benson cycle only
C) the Embden-Meyerhof pathway only
D) both the Embden-Meyerhof and Calvin-Benson cycle pathways
E) both the pentose phosphate and Entner-Doudoroff pathways

Question 10

The electron transport chain provides the energy for

A) oxidative phosphorylation.
B) substrate-level phosphorylation.
C) beta-oxidation.
D) photophosphorylation.
E) anabolic reactions.

Question 11

Pyruvic acid is a product of

A) the Krebs cycle.
B) fermentation.
C) glycolysis.
D) the pentose phosphate pathway.
E) both fermentation and the Krebs cycle.

Question 12

Which of the following is a non-protein carrier found in some electron transport chains?

A) flavoproteins
B) metal-containing proteins
C) ribozymes
D) cytochromes
E) ubiquinones

Question 13

Which of the following statements concerning cellular metabolism is FALSE?

A) Energy obtained from nutrients or light is stored in the bonds of ATP.
B) Enzymes are used in both catabolic and anabolic reactions.
C) Macromolecules are converted into cell structures via catabolism.
D) The goal of metabolism is reproduction of the organism.
E) ATP is used in the formation of macromolecules.

Question 14

Which of the following statements concerning glycolysis is TRUE?

A) The first step of glycolysis involves oxidative phosphorylation.
B) The glycolytic pathway is cyclical.
C) Glucose is activated by substrate-level phosphorylation.
D) Ribulose 5-phosphate is an intermediate of glycolysis.
E) Two NADH molecules are reduced during glycolysis.

Question 15

Many vitamins are important ________ of enzymes.

A) protein cofactors
B) coenzymes
C) allosteric inhibitors
D) competitive inhibitors
E) activators

Question 16

Anaerobic bacteria may use ________ as the final electron acceptor during anaerobic respiration.

A) nitrate only
B) carbon dioxide only
C) sulfate only
D) both nitrate and sulfate
E) carbon dioxide, nitrate and sulfate

Question 17

All of the following are forms of oxidation EXCEPT

A) loss of an electron.
B) loss of hydrogen atom.
C) a dehydrogenation event.
D) substrate-level phosphorylation.
E) gain of an oxygen atom and its electrons.

Question 18

Which of the following is a fermentation product useful in the manufacture of cheese?

A) acetic acid
B) ammonia
C) ethanol
D) lactic acid
E) pyruvic acid

Question 19

Which of the following is an active enzyme?

A) apoenzyme
B) cofactor
C) coenzyme
D) holoenzyme
E) subtrate

Question 20

The various types of chlorophyll differ in the

A) amount of light they can absorb.
B) amount of ATP they produce.
C) number of electrons they release.
D) amount of oxygen they utilize.
E) wavelengths of light they absorb.

Question 21

Although glycolysis requires an input of ATP, this pathway results in a net gain of two ATP; therefore it is a(n) ________ pathway.

A) exergonic
B) endergonic
C) oxidative
D) reductive
E) neither exergonic nor endergonic

Question 22

The metabolic processes called fermentation

A) produce substrates for the Krebs cycle.
B) are alternatives for the pentose phosphate pathway.
C) use an organic molecule as a final electron acceptor.
D) occur only when oxygen is readily available.
E) produce substrates for glycolysis.

Question 23

The energy captured by photophosphorylation is used to produce glucose

A) through the Calvin-Benson cycle.
B) through the Krebs cycle.
C) by cyclic phosphorylation.
D) through the pentose-phosphate pathway.
E) by beta-oxidation.

Question 24

Bacteriochlorophyll a absorbs ________ light.

A) 350 nm, ultraviolet
B) 425 nm, violet
C) 660 nm, red
D) both 425 & 660 nm (violet and red)
E) all visible

Question 25

Noncyclic photophosphorylation produces

A) ATP only.
B) oxygen.
C) NADPH only.
D) ATP and NADPH.
E) water and ATP.

Question 26

The conversion of pyruvic acid to acetyl-CoA can be described as ________, because a molecule of CO₂ is produced as a by-product.

A) decarboxylation
B) amination
C) respiration
D) oxidation
E) phosphorylation

Question 27

When a cell forms an amino acid by adding an amine group derived from ammonia to a precursor metabolite, this process is called

A) amination.
B) transamination.
C) reduction.
D) polymerization.
E) deamination.

Question 28

Enzymes known as lyases participate in ________ reactions.

A) anabolic
B) catabolic
C) both anabolic and catabolic
D) neither anabolic nor catabolic
E) oxidation-reduction

Question 29

Beta-oxidation of fatty acids produces a substrate of the

A) pentose phosphate pathway.
B) protein synthesis pathways.
C) Embden-Meyerhof pathway.
D) Krebs cycle.
E) Calvin-Benson cycle.

Question 30

During the synthesis of acetyl-CoA from pyruvic acid, ________ is produced.

A) ATP
B) NADH
C) FADH₂
D) H₂O
E) acetic acid

Question 31

During reactions catalyzed by oxidoreductases an electron donor is

A) oxidized.
B) reduced.
C) synthesized.
D) degraded.
E) unaltered.

Question 32

Hydrolases are generally involved in ________ reactions.

A) anabolic
B) catabolic
C) both anabolic and catabolic
D) neither anabolic nor catabolic
E) oxidation-reduction

Question 33

If a cell reverses the process of beta-oxidation, which of the following molecules will it make?

A) glycerol
B) amino acids
C) fatty acids
D) nucleotides
E) starch

Question 34

Which of the following is associated with the Calvin-Benson cycle?

A) acetyl-CoA
B) TMAO
C) RuBP
D) FADH₂
E) PABA

Question 35

The reactions of photosynthesis take place in the ________ of prokaryotes.

A) thylakoids
B) cytoplasm
C) nucleoid
D) cristae
E) outer membrane

Question 36

Which of the following is TRUE concerning the structure and function of enzymes?

A) All enzymes bind cofactors necessary for their function.
B) An apoenzyme is a combination of a cofactor bound to a holoenzyme.
C) Enzymes can function at a wide range of pH.
D) Competitive inhibition of an enzyme occurs when an inhibitor binds to an allosteric site on the enzyme.
E) After an enzyme has catalyzed a reaction, it resumes its original shape and can interact with a new substrate molecule.

Question 37

The conversion of amino acids to carbohydrates is an example of

A) amination.
B) gluconeogenesis.
C) substrate-level phosphorylation.
D) beta-oxidation.
E) electron transport.

Question 38

Which of the following metabolic processes is commonly used to identify bacteria?

A) carbohydrate fermentation
B) lipid catabolism
C) Krebs cycle products
D) lipid synthesis
E) pentose phosphate pathway products

Question 39

Chemical reactions that can proceed toward either anabolism or catabolism are called

A) glycolytic.
B) light-independent.
C) synthetic.
D) cyclic.
E) amphibolic.

Question 40

Where is the majority of ATP generated in prokaryotic cells?

A) in the cytoplasmic membrane
B) in the cytosol
C) in the thylakoids
D) in the inner mitochondrial membrane
E) on ribosomes

Question 41

Another term for a protein catalyst is a(n) (enzyme/ribozyme).

Question 42

A(n) (oxidation/reduction/transport) reaction is one in which a molecule accepts an electron.

Question 43

The production of NADH takes place during the ________ stage(s) of glycolysis.

A) energy-conservation
B) energy-investment
C) lysis
D) lysis and energy-investment
E) energy-investment and energy-conservation

Question 44

During chemiosmosis, electrons are pumped across a membrane to produce ATP.

Question 45

The process illustrated in the figure above is an example of a(n) ________ reaction.

A) amination
B) reduction
C) oxidation
D) transamination
E) transferase

Question 46

The conversion of phosphoenol pyruvic acid (PEP) to pyruvic acid results in the production of an ATP. This reaction is an example of (substrate-level/oxidative/reductive) phosphorylation.

Question 47

Identify the processes of glucose metabolism represented in Figure 5.1.

A) A = electron transport chain, B = Krebs cycle, C = glycolysis, D = fermentation
B) A = glycolysis, B = fermentation, C = Krebs cycle, D = electron transport chain
C) A = fermentation, B = glycolysis, C = Krebs cycle, D = electron transport chain
D) A = glycolysis, B = Krebs cycle, C = fermentation, D = electron transport chain
E) A = glycolysis, B = Krebs cycle, C = electron transport chain, D = fermentation

Question 48

As the concentration of substrate increases, the activity of the enzyme decreases.

Question 49

All the precursors of amino acids are intermediates of glycolytic and fermentation pathways.

Question 50

The (activation /inhibition/saturation) point of an enzyme is reached when all active sites have bound substrate molecules.

Question 51

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

Question 52

Substrate-level phosphorylation occurs during which of the following stage(s) of glucose catabolism?

A) formation of acetyl-CoA
B) lysis stage of glycolysis
C) energy-conservation stage of glycolysis
D) Krebs cycle
E) formation of acetyl-CoA and the Krebs cycle

Question 53

Accumulation of a metabolic pathway product may result in decreased activity of the pathway enzymes.

Question 54

The pentose phosphate pathway generates all the necessary precursors for nucleotide biosynthesis.

Question 55

Reactions that are both catabolic and anabolic are amphibolic.

Question 56

All substrates for ribozymes are RNA molecules.

Question 57

The amount of energy required for a reaction to occur is its activation energy.

Question 58

Glyceraldehyde 3-phosphate is an intermediate in the Calvin-Benson cycle.

Question 59

Which of the following is the CORRECT sequence of stages in glycolysis?

A) energy-conservation, energy-investment, lysis
B) lysis, energy-investment, energy-conservation
C) energy-investment, lysis, energy-conservation
D) lysis,energy-conservation, energy-investment
E) energy-investment, energy-conservation, lysis

Question 60

Reactions involving ligases are typically ________ reactions.

A) anabolic
B) catabolic
C) both anabolic and catabolic
D) neither anabolic nor catabolic
E) exergonic

Question 61

Some bacteria use (acetyl-CoA/DHAP/TMAO) as a final electron receptor, resulting in a detectable odor.

Question 62

The discussion of carbohydrate catabolism includes some of the many metabolic variations microbes are capable of. Devise a set of biochemical tests to identify the Gram-negative bacteria mentioned. Assume you can detect various organic compounds. Prepare a dichotomous key of your identification scheme.

Question 63

Laboratory fermentation tests often include a pH indicator because many bacteria produce (O₂/bases/acids) as they ferment carbohydrates.

Question 64

Cells can use (active/allosteric/substrate) sites to regulate enzyme activity and thereby control their metabolism.

Question 65

Beta-oxidation of fatty acids produces (acetic acid/acetyl-CoA/glycerol).

Question 66

Anaerobic respiration involves the use of molecules other than oxygen as the final electron (acceptor/donor) in an electron transport chain.

Question 67

Discuss the interrelationships between anabolic and catabolic pathways. Provide specific examples in your answer.

Question 68

Significant amounts of the NADPH required for the Calvin-Benson cycle are produced during the (cyclic/noncyclic) photophosphorylation reactions of photosynthesis.

Question 69

Compare and contrast cyclic and noncyclic photophosphorylation.

Question 70

Amino acids are converted to substrates of the Krebs cycle by (beta-oxidation/deamination/transamination).

Question 71

Explain why the ATP yield from processes such as cellular respiration is generally given as a theoretical number.

Question 72

Describe the mechanism of feedback inhibition and the role this process plays in controlling enzyme activity.

Question 73

Anoxygenic photosynthesis typically results in the production of (oxygen/sulfur/ammonia) as a waste product.

Question 74

Electrons are transferred in the Krebs cycle in the form of (oxygen/hydrogen) atoms to NAD+ and FAD.

Question 75

Only Photosystem I is required for (anoxygenic/cyclic/noncyclic) photophosphorylation to occur.

Question 76

The purpose of electron transport is to create a proton (concentration/gradient/pump) across a membrane that can then be used to make ATP.

Question 77

When a noncompetitive inhibitor molecule binds to a(n) (active/allosteric/substrate) site on an enzyme, the shape of the active site changes so that the substrate molecules can no longer bind.