Deck 5: Microbial Metabolism

Question 1

Pyruvic acid is a product of

A) the Entner- Doudoroff pathway only.
B) the Krebs cycle.
C) both glycolysis and the Entner- Doudoroff pathway.
D) fermentation.
E) glycolysis only.

Answer 1

C

Question 2

The metabolic processes called fermentation

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

Answer 2

B

Question 3

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

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

Answer 3

D

Question 4

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) competitive inhibition.
B) excitatory allosteric control.
C) feedback inhibition.
D) noncompetitive inhibition.
E) allosteric inhibition.

Question 5

Reactions involving ligases are typically reactions.

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

Question 6

Isomerases catalyze reactions in which

A) biomolecules are broken down into their component parts.
B) groups are transferred from one molecule to another.
C) biomolecules are oxidized or reduced.
D) atoms in biomolecules are rearranged.
E) biomolecules are assembled from smaller molecules.

Question 7

Which of the following statements concerning enzymes is FALSE?

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

Question 8

Which of the following statements concerning glycolysis is TRUE?

A) It produces ATP by oxidative phosphorylation.
B) It is an alternative to fermentation.
C) It both requires the input of ATP and produces ATP.
D) It occurs in the cell membranes of bacteria.
E) It involves ribulose 5- phosphate as an intermediate.

Question 9

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

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

Question 10

Which of the following products of glucose catabolism is a substrate for fatty acid synthesis?

A) phosphoglyceric acid
B) succinyl- CoA
C) oxaloacetate
D) pyruvic acid
E) acetyl- CoA

Question 11

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

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

Question 12

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

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

Question 13

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

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

Question 14

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 15

Which of the following produces NADPH?

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

Question 16

During reactions catalyzed by oxidoreductases an electron donor is

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

Question 17

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

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

Question 18

The molecule that an enzyme acts upon is known as its

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

Question 19

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

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

Question 20

Substrate- level phosphorylation occurs during the stage(s) of glycolysis.

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

Question 21

Where is the majority of ATP generated in most eukaryotic cells?

A) in the mitochondrial matrix
B) in the cytoplasmic membrane
C) on ribosomes
D) in the cytosol
E) in the outer membrane of the mitochondria

Question 22

All of the following are aspects of a cell's ability to regulate its metabolism EXCEPT

A) synthesis or degradation of membrane transport proteins.
B) synthesis of a catabolic enzyme only when its substrate is available.
C) use of the most energy- efficient energy source available.
D) use of the same coenzymes for anabolic and catabolic reactions that share substrate molecules.
E) isolation of various enzymes within membranous organelles.

Question 23

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

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

Question 24

Photosystems are assembled in

A) thylakoids.
B) grana.
C) cytochromes.
D) cristae.
E) stroma.

Question 25

The various types of chlorophyll differ in the

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

Question 26

Which of the following statements concerning cellular metabolism is FALSE?

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

Question 27

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

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

Question 28

Hydrolases are generally involved in reactions.

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

Question 29

A catabolic process which occurs in eukaryotic mitochondria is

A) Calvin- Benson cycle.
B) Entner- Doudoroff pathway.
C) deamination.
D) fermentation.
E) beta- oxidation.

Question 30

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

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

Question 31

The conversion of amino acids to carbohydrates is an example of

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

Question 32

What is the major product of the Calvin- Benson cycle that can then be used to form glucose?

A) RuBP
B) NADPH
C) CO2
D) glyceraldehyde 3- phosphate
E) ATP

Question 33

Which of the following is required for holoenzyme function?

A) a substrate
B) a coenzyme
C) an activator
D) an allosteric inhibitor
E) a protein cofactor

Question 34

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

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

Question 35

What is the purpose of the light- dependent reactions of photosynthesis?

A) production of ATP and NADPH
B) production of ATP and NADH
C) production of oxygen
D) regeneration of NAD+
E) carbon fixation

Question 36

Identify the processes of glucose metabolism represented in Figure 5- 1.

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

Question 37

All of the following are forms of oxidation EXCEPT

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

Question 38

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

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

Question 39

Glycolysis begins with a(n) stage(s).

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

Question 40

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

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

Question 41

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

Question 42

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

Question 43

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

Question 44

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 45

During glycolysis, glucose is converted to (pyruvic/acetic/lactic) acid, a molecule that can be used in either fermentation or respiration pathways.

Question 46

Anabolic reactions may be characterized as

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

Question 47

Laboratory fermentation tests often include a pH indicator because many bacteria produce (CO2/bases/acids) as they ferment carbohydrates.

Question 48

Enzymes increase the rate of reaction by lowering the (activation/reaction) energy.

Question 49

Which of the following can be the final electron acceptor in anaerobic respiration in bacteria?

A) nitrate only
B) sulfate only
C) pyruvic acid only
D) both nitrate and sulfate
E) nitrate, pyruvic acid, and sulfate

Question 50

Waste products such as sulfur are produced by (oxygenic/anoxygenic/aerobic) photosynthetic bacteria as they obtain electrons for noncyclic photophosphorylation.

Question 51

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

Question 52

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

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

Question 53

Light energy is used to fuel the assembly of carbon dioxide and water into carbohydrates in the process known as

A) oxidation.
B) fermentation.
C) chemiosmosis.
D) photosynthesis.
E) gluconeogenesis.

Question 54

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

Question 55

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

Question 56

The (transferases/transaminases/deaminases) generate amino acids from carbohydrate precursors and glutamic acid.

Question 57

A (photosystem/thylakoid/grana) is a collection of pigments such as chlorophyll that are used to absorb light in the light- dependent reactions of photosynthesis.

Question 58

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

Question 59

Which of the following statements concerning reduction reactions is FALSE?

A) A molecule gains a hydrogen atom.
B) An electron acceptor becomes more positively charged.
C) An electron acceptor gains an electron.
D) They are coupled with oxidation reactions.
E) They frequently involve electron carrier molecules.

Question 60

Beta- oxidation of fatty acids produces a substrate of the

A) Entner- Doudoroff pathway.
B) Embden- Meyerhof pathway.
C) Krebs cycle.
D) pentose phosphate pathway.
E) Calvin- Benson cycle.

Question 61

Reactions that are both catabolic and anabolic are amphibolic.

Question 62

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) phosphorylation.

Question 63

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

Question 64

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

Question 65

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

Question 66

Synthesis of the precursors of purines and pyrimidines requires transamination of ribose- 5- phosphate.

Question 67

The ability to utilize different metabolites for cellular respiration is one method for identifying bacteria.

Question 68

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

Question 69

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

Question 70

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 71

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

Question 72

Ribozymes are enzymes that cleave the subunits of the ribosome.

Question 73

Some photosynthetic bacteria use chlorophylls other than chlorophyll a.

Question 74

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

Question 75

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

Question 76

Compare and contrast cyclic and noncyclic photophosphorylation.

Question 77

Environmental changes can result in the inactivation of enzymes.