Deck 5: Microbial Metabolism

Question 1

Which of the following compounds is NOT an enzyme?

A)dehydrogenase
B)cellulase
C)coenzyme A
D)β-galactosidase
E)sucrase

Answer 1

C

Question 2

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

A)Electrons are passed through a series of carriers to O₂.
B)A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels,releasing energy that is used to generate ATP.
C)ATP is directly transferred from a substrate to ADP.
D)Electrons are passed through a series of carriers to an organic compound.

Answer 2

B

Question 3

Figure 5.1
Which compound is being reduced in the reaction shown in Figure 5.1?

A)isocitric acid and α-ketoglutaric acid
B)α-ketoglutaric acid and NAD⁺
C)NAD⁺
D)NADH
E)NADH and isocitric acid

Answer 3

C

Question 4

From the list below,which is NOT produced during the Krebs cycle?

A)FADH₂
B)NADH
C)ATP
D)NADPH
E)CO₂

Question 5

In noncyclic photophosphorylation,O₂ is released from

A)CO₂.
B)2H₂O.
C)C₆H₁₂O₆.
D)sunlight.
E)chlorophyll.

Question 6

A bacterium that only possesses the ability to ferment obtains energy

A)by glycolysis only.
B)by aerobic respiration only.
C)by fermentation or aerobic respiration.
D)only in the absence of oxygen.
E)only in the presence of oxygen.

Question 7

Figure 5.3
How would a noncompetitive inhibitor interfere with a reaction involving the enzyme shown in Figure 5.3?

A)It would bind to a.
B)It would bind to b.
C)It would bind to c.
D)It would bind to d.
E)The answer cannot be determined based on the information provided.

Question 8

Figure 5.5
Which of the graphs in Figure 5.5 best illustrates the activity of an enzyme that is saturated with substrate?

A)a
B)b
C)c
D)d
E)e

Question 9

Which biochemical process is NOT used during glycolysis?

A)substrate-level phosphorylation
B)oxidation-reduction
C)carbohydrate catabolism
D)beta oxidation
E)enzymatic reactions

Question 10

Figure 5.2
What type of reaction is in Figure 5.2?

A)decarboxylation
B)transamination
C)dehydrogenation
D)oxidation
E)reduction

Question 11

Fatty acids are oxidized in

A)the Krebs cycle.
B)the electron transport chain.
C)glycolysis.
D)the pentose phosphate pathway.
E)the Entner-Doudoroff pathway.

Question 12

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

A)precursors for nucleic acids.
B)precursors for the synthesis of glucose.
C)three ATPs.
D)NADPH.
E)precursors for the synthesis of amino acids.

Question 13

Which of the following statements about photophosphorylation is FALSE?

A)Light liberates an electron from chlorophyll.
B)The oxidation of carrier molecules releases energy.
C)Energy from oxidation reactions is used to generate ATP from ADP.
D)It requires CO₂.
E)It occurs in photosynthesizing cells.

Question 14

Which of the following statements about anaerobic respiration is FALSE?

A)It yields lower amounts of ATP when compared to aerobic respiration.
B)The complete Krebs cycle is utilized.
C)It involves the reduction of an organic final electron acceptor.
D)It generates ATP.
E)It requires cytochromes.

Question 15

Which organism is NOT correctly matched to its energy source?

A)photoheterotroph - light
B)photoautotroph - CO₂
C)chemoautotroph - Fe²⁺
D)chemoheterotroph - glucose
E)chemoautotroph - NH₃

Question 16

All of the following are required in the reactions of microbial respiration EXCEPT

A)electron transport system.
B)cytochromes.
C)a source of electrons.
D)oxygen.
E)final electron acceptor.

Question 17

Increasing the temperature of a reaction will do all of the following EXCEPT

A)increase the reaction rate.
B)increase the number of molecules attaining activation energy.
C)increase the number of molecular collisions.
D)increase the activation energy.
E)increase kinetic energy of the molecules.

Question 18

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 oxidized in the electron transport chain.
D)It is catabolized in glycolysis.
E)It is converted into acetyl CoA.

Question 19

Which of the following is the best definition of fermentation?

A)the partial reduction of glucose to pyruvic acid
B)the partial oxidation of glucose with organic molecules serving as electron acceptors
C)the complete catabolism of glucose to CO₂ and H₂O
D)the production of energy by oxidative-level phosphorylation
E)the production of energy by both substrate and oxidative phosphorylation

Question 20

Figure 5.4
How is ATP generated in the reaction shown in Figure 5.4?

A)glycolysis
B)fermentation
C)photophosphorylation
D)oxidative phosphorylation
E)substrate-level phosphorylation

Question 21

Which of the following uses glucose for carbon and energy?

A)chemoautotroph
B)chemoheterotroph
C)photoautotroph
D)photoheterotroph

Question 22

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

A)Krebs cycle
B)glycolysis
C)pentose phosphate pathway
D)Krebs cycle and glycolysis

Question 23

Figure 5.7
The graph at the left in Figure 5.7 shows the reaction rate for an enzyme at its optimum temperature.Which graph shows enzyme activity at a higher temperature?

A)a
B)b
C)c
D)d

Question 24

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

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

Question 25

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

A)CO₂.
B)H₂O.
C)C₆H₁₂O₆.
D)H₂S.
E)chlorophyll.

Question 26

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.

A)2,4,5
B)1,3,4
C)2,3,5
D)1,2,3
E)All of the statements are true.

Question 27

Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol.The yeasts are growing well on the maltose medium but are not producing alcohol.What is the most likely explanation?

A)The maltose is toxic.
B)O₂ is in the medium.
C)Not enough protein is provided.
D)The temperature is too low.
E)The temperature is too high.

Question 28

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

A)Two pyruvate molecules are generated.
B)Four ATP molecules are generated via substrate-level phosphorylation.
C)Two NADH molecules are generated.
D)One molecule of ATP is expended.
E)Two molecules of water are generated.

Question 29

A bacterium such as Pseudomonas uses nitrate as a final electron acceptor in an electron transport system.All the below statements are true EXCEPT

A)the process does not yield as much ATP.
B)they can respire without O₂.
C)they require light.
D)the process produces nitrite ion.
E)the process requires an electron donor.

Question 30

Which of the following statements regarding metabolism is FALSE?

A)Heat may be released in both anabolic and catabolic reactions.
B)ATP is formed in catabolic reactions.
C)ADP is formed in anabolic reactions.
D)Anabolic reactions are degradative.

Question 31

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

A)aerobic respirers.
B)anaerobic respirers.
C)heterolactic fermenters.
D)homolactic fermenters.
E)alcohol fermenters.

Question 32

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

A)increase (become more alkaline).
B)decrease (become more acidic).
C)stay the same.

Question 33

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

A)It involves glycolysis.
B)It involves the pentose phosphate pathway.
C)NADH is generated.
D)ATP is generated.
E)NADH and ATP are generated.

Question 34

Figure 5.8

In Figure 5.8,where is ATP produced?

A)a
B)b
C)c
D)d
E)e

Question 35

Gallionella bacteria can get energy from the reaction Fe²⁺ → Fe³⁺.This reaction is an example of

A)oxidation.
B)reduction.
C)fermentation.
D)photophosphorylation.
E)the Calvin-Benson cycle.

Question 36

Figure 5.6
The rates of O₂ and glucose consumption by a bacterial culture are shown in Figure 5.6.Assume a bacterial culture was grown in a glucose medium without O₂.Then O₂ was added at the time marked X.The data indicate that

A)these bacteria don't use O₂.
B)these bacteria get more energy anaerobically.
C)aerobic metabolism is more efficient than fermentation.
D)these bacteria cannot grow anaerobically.

Question 37

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

A)chemoautotroph
B)chemoheterotroph
C)photoautotroph
D)photoheterotroph

Question 38

Cyanobacteria are a type of

A)chemoautotroph.
B)chemoheterotroph.
C)photoautotroph.
D)photoheterotroph.

Question 39

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

A)chemoautotroph
B)chemoheterotroph
C)photoautotroph
D)photoheterotroph

Question 40

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

A)fermenting the glucose.
B)oxidizing the glucose.
C)using the peptides.
D)not growing.

Question 41

Figure 5.8

What is the most acidic place in Figure 5.8?

A)a
B)b
C)c
D)d
E)e

Question 42

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

Question 43

Figure 5.8

Refer to Figure 5.8.In aerobic respiration,where is water formed?

A)a
B)b
C)c
D)d
E)e

Question 44

Researchers are developing a ribozyme that cleaves the HIV genome.This pharmaceutical agent could be described as

A)an RNA molecule capable of catalysis.
B)a hydrolase.
C)a genetic transposable element.
D)a protease inhibitor.
E)a competitive inhibitor for reverse transcriptase.

Question 45

Figure 5.8

In Figure 5.8,the structure labeled "1" is

A)NAD⁺.
B)ATP synthase.
C)a plasma membrane.
D)a cell wall.
E)cytoplasm.

Question 46

Insert non-labeled graph from page 150- replica created and inserted below
The graph shows the normal reaction rate of an enzyme and the reaction rate when a competitive inhibitor is present.Which description below explains the appearance of the graph?

A)As the substrate concentration increases,the activity of the enzyme decreases.
B)As the substrate concentration increases,the effect of the inhibitor was overcome and enzyme activity was restored.
C)As the enzyme concentration increased,the effect of the inhibitor was overcome and enzyme activity was restored.
D)As the enzyme concentration increased,the effect of the inhibitor was more pronounced.
E)As the competitive inhibitor concentration decreased,the reaction rate also decreased.

Question 47

A urease test is used to identify Mycobacterium tuberculosis because

A)urease is a sign of tuberculosis.
B)M)tuberculosis produces urease.
C)urea accumulates during tuberculosis.
D)some bacteria reduce nitrate ion.
E)M)bovis can cause tuberculosis.

Question 48

Figure 5.8

In Figure 5.8,the path labeled "2" is the flow of

A)electrons.
B)protons.
C)energy.
D)water.
E)glucose.

Question 49

Which statements correspond to amphibolic pathways? 1.Anabolic and catabolic reactions are joined through common intermediate.
2)They are shared metabolic pathways.
3)Feedback inhibition can help regulate rates of reactions.
4)Both types of reactions are necessary but do not occur simultaneously.

A)1 only
B)1,2,3
C)1,2,3,4
D)2,4
E)2,3,4

Question 50

Glycolysis is utilized by cells in both respiration and fermentation.

Question 51

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

Question 52

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

Question 53

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

Question 54

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

Question 55

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

Question 56

Why do eukaryotes generate only about 36 ATP per glucose in aerobic respiration but prokaryotes may generate about 38 ATP?

A)eukaryotes have a less efficient electron transport system.
B)eukaryotes do not transport as much hydrogen across the mitochondrial membrane as prokaryotes do across the cytoplasmic membrane.
C)eukaryotes must shuttle pyruvate across the mitochondrial membrane by active transport.
D)eukaryotes do not completely oxidize glucose in their respiration reactions.
E)prokaryotes possess an alternate to the Krebs cycle that generates more reduced electron.carriers.

Question 57

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

Question 58

In non-cyclic photophosphorylation,excited electrons ultimately

A)return to chlorophyll.
B)are used to form water.
C)combine with hydrogen ions and NADP+ to produce NADPH.
D)flow through ATP synthase.
E)generate light within the spectrum of green wavelengths.

Question 59

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

Question 60

Catabolic reactions are generally degradative and hydrolytic.

Question 61

Compare and contrast photophosphorylation and oxidative phosphorylation.

Question 62

Explain the overall purpose of metabolic pathways.

Question 63

Differentiate the following two laboratory tests: starch hydrolysis and starch fermentation.

Question 64

Streptococcus lacks an electron transport chain.How does this bacterium reoxidize NADH? Where is the NADH formed?

Question 65

Rhodopseudomonas is an anaerobic photoautotroph that uses organic compounds as an electron donor.It is also capable of chemoheterotrophic metabolism.Diagram the metabolic pathways of this bacterium.

Question 66

Summarize energy production in cells in a single sentence.

Question 67

You look in the refrigerator and find some orange drink you had forgotten was there.The drink now has an "off" taste and bubbles.What is the most likely explanation for the changes in the drink?