Deck 13: Metabolism

Question 1

How do enzymes increase the rate of a biochemical reaction?

A) By lowering the activation energy.
B) By increasing the standard free energy.
C) By lowering the standard free energy.
D) By increasing the activation energy.
E) By lowering the reduction potential.

Answer 1

A

Question 2

Which of these is the most widely used form of energy in cell processes?

A) glucose
B) NADH
C) pyruvate
D) ATP
E) citrate

Answer 2

D

Question 3

Microorganisms that rely solely on fermentation reactions for energy production make ATP primarily by this method.

A) oxidative phosphorylation
B) electron transport phosphorylation
C) membrane bound ATPase
D) substrate-level phosphorylation
E) the oxidation of NADH

Answer 3

D

Question 4

How is the activity of an allosteric enzyme regulated?

A) By a coenzyme.
B) By covalent modification.
C) Through the binding of an effector molecule.
D) Through the binding of a competitive inhibitor.
E) By substrate binding.

Question 5

Oxidative phosphorylation uses ALL of the following for energy production EXCEPT:

A) electrons from NADH.
B) membrane-associated electron transport chain.
C) an ATP synthase.
D) phosphoenolpyruvate.
E) a proton motive force.

Question 6

Which of these is TRUE for a chemoorganoheterotroph?

A) Uses inorganic carbon as an energy source and organic carbon as a carbon source.
B) Uses inorganic carbon as an electron source and organic carbon as a carbon source.
C) Uses organic carbon as an electron source and inorganic carbon as a carbon source.
D) Uses organic carbon as an electron source and a carbon source.
E) Uses inorganic carbon as an energy source and a carbon source.

Question 7

A chemical reaction that has a negative ΔG⁰

A) is an endergonic reaction.
B) will require an input of energy.
C) is not a spontaneous reaction.
D) is an energy yielding reaction.
E) will absorb energy.

Question 8

Cyanobacteria carry out oxygenic photosynthesis producing oxygen as a byproduct from the oxidation of water,which serves as the electron donor for the light-dependent reactions.How would cyanobacteria be classified?

A) chemoorganoautotroph
B) chemoorganoheterotroph
C) photolithoheterotroph
D) photoorganoautotroph
E) photolithoautotroph

Question 9

The standard reduction potential (E₀')for ferredoxin (Fdₒₓ/Fdᵣₑd)is (-0.43 V).Based on this,which of these would you expect to be true?

A) Oxidized ferredoxin to be a good electron donor.
B) Oxidized ferredoxin to be a good electron acceptor.
C) Reduced ferredoxin to be a good electron donor.
D) Reduced ferredoxin to be a good electron acceptor.
E) Cannot be determined without knowledge of the other reactant.

Question 10

The biochemical reaction,PEP + ADP → Pyruvate + ATP,is an example of which of these?

A) An oxidation/reduction reaction.
B) Oxidative phosphorylation.
C) Substrate-level phosphorylation.
D) An aldolase catalyzed reaction.
E) An electron transport reaction.

Question 11

What are the NET products of the Embden-Meyerhof pathway,when operating in the catabolic direction?

A) Two pyruvate, two ATP, and two NADH.
B) Two pyruvate, four ATP, and four NADH.
C) Two CO₂, four pyruvate, two ATP, and four NADH.
D) Two CO₂, two pyruvate, four ATP, and four NADH.
E) Two CO₂, two pyruvate, two ATP, and two NADH.

Question 12

When oxygen reacts with hydrogen gas,water is produced as the product in this oxidation-reduction reaction.Hydrogen donates electrons to oxygen in the reaction.Which statement below is true about this reaction?

A) Oxygen is oxidized to water.
B) Oxygen is being reduced in the reaction.
C) Hydrogen is being reduced in the reaction.
D) The electron donor in this reaction is reduced.
E) The electron acceptor in this reaction is oxidized.

Question 13

Which of these is an example of a coenzyme?

A) glucose
B) iron
C) NAD⁺
D) cytochrome c
E) a kinase

Question 14

The products of yeast fermentation,when including the Embden-Meyerhof pathway of glycolysis for one molecule of glucose,are two ethanol molecules as well as these others.

A) two ATP and two NADH
B) two ATP, two NADH, and two CO₂
C) four ATP and two NADH
D) two ATP and two CO₂
E) four ATP, two NADH, and two CO₂

Question 15

Lactic acid is a common fermentation product.It is produced when ___________ is reduced by electrons received from NADH.

A) ethanol
B) glucose
C) pyruvate
D) acetyl-CoA
E) 3-phosphoglyceraldehyde

Question 16

Which of these is TRUE for a chemolithoautotroph?

A) inorganic molecules as energy sources and inorganic carbon as a carbon source.
B) organic molecules as electron sources and inorganic carbon as a carbon source.
C) organic molecules as energy sources and organic carbon as a carbon source.
D) inorganic molecules as electron sources and organic carbon as a carbon source.
E) inorganic molecules as energy sources and organic carbon as a carbon source.

Question 17

How many NET molecules of ATP are produced during the Embden-Meyerhof pathway of glycolysis for every molecule of glucose that is converted into two molecules of pyruvate?

A) one
B) two
C) four
D) six
E) ten

Question 18

What does a large positive ΔE₀' indicate for a redox reaction?

A) It is endergonic.
B) It has a positive ΔG⁰'.
C) It will require an input of energy.
D) It is spontaneous.
E) It is energetically unfavorable.

Question 19

Which of these are important products of the pentose phosphate pathway that are used in biosynthesis?

A) pyruvate, ribose-5-phosphate, and NADPH
B) NADPH, ribose-5-phosphate, and erythrose-4-phosphate
C) pyruvate, citrate, and erythrose-4-phosphate
D) pyruvate, erythrose-4-phosphate, and ribose-5-phosphate
E) citrate, NADPH, and ribose-5-phosphate

Question 20

Fermentation can most accurately be described by which of these?

A) The reoxidation of NADH by an electron transport chain.
B) A process that occurs in the absence of oxygen.
C) An energy producing process found in all anaerobes.
D) The direct reoxidation of NADH by an internal organic molecule.
E) The use of a terminal electron acceptor other than oxygen.

Question 21

Some anoxygenic photosynthetic bacteria are able to use _______ as an electron source.

A) light
B) CO₂
C) H₂S
D) H₂O
E) nitrate

Question 22

What is the chromophore of the chlorophyll molecule composed of?

A) A carotenoid molecule with an atom of iron in the center.
B) A porphyrin molecule with an atom of iron in the center.
C) A phycoerythrin with an atom of iron in the center.
D) A porphyrin molecule with an atom of magnesium in the center.
E) A phycoerythrin molecule with an atom of magnesium in the center.

Question 23

Enzymes that break down proteins into individual amino acids.

A) amylases
B) proteases
C) reductases
D) dehydrogenases
E) lipases

Question 24

Which of these occurs in anaerobic respiration,but not in aerobic respiration?

A) A fermentation product is produced.
B) The terminal cytochrome oxidase is replaced by a cytochrome reductase.
C) Glucose is only partially oxidized to CO₂.
D) NADH dehydrogenase is replaced by NADH oxidase.
E) Glycolysis.

Question 25

What can the proton motive force generated by the electron transport system be used for?

A) NADH oxidation, ATP synthesis, and flagella rotation
B) NADH oxidation, ATP synthesis, and nutrient transport
C) ATP synthesis, flagella rotation, and nutrient transport
D) NADH oxidation, flagella rotation, and nutrient transport
E) oxygen reduction and ATP synthesis

Question 26

The product(s)of the light reactions of photosynthesis.

A) glucose and ATP
B) glucoseonly
C) ATPonly
D) glucose and NADPH
E) ATP and NADPH

Question 27

How is ATP is primarily produced in chemolithotrophs?

A) Fermentation reactions.
B) Anaerobic respiration.
C) Electrons moving through an electron transport system to generate a proton motive force.
D) Glycolysis and TCA cycle reactions.
E) Using reduced inorganic molecules as electron acceptors for the electron transport system.

Question 28

Term for the primary pathway for fatty acid oxidation?

A) Calvin cycle
B) pentose phosphate pathway
C) Parnas pathway
D) β-oxidation pathway
E) reductive TCA pathway

Question 29

Which of these sets are products of the TCA (Krebs)Cycle?

A) NADH, ATP, CO₂, and oxaloacetate
B) NADH, FADH₂, and ATP
C) NADH, FADH₂, and oxaloacetate
D) NADH, FADH₂, CO₂, and ATP
E) NADH, FADH₂, CO₂, and oxaloacetate

Question 30

Which of the following would NOT be appropriate as a terminal electron acceptor during anaerobic respiration?

A) nitrate (NO₃⁻)
B) sulfate (SO₄²⁻)
C) sulfur (S⁰)
D) ferric iron (Fe³⁺)
E) hydrogen sulfide (H₂S)

Question 31

Cyanobacteria use _______ as an electron source for the reduction of NADP+.

A) sulfur
B) glucose
C) water
D) carbon dioxide
E) nitrate

Question 32

Which of these is NOT an electron carrier used in the electron transport system?

A) flavoproteins
B) iron-sulfur proteins
C) ATPase
D) quinones
E) cytochromes

Question 33

Which organisms contain bacteriochlorophyll?

A) cyanobacteria
B) cyanobacteria and purple non-sulfur bacteria
C) cyanobacteria and green sulfur bacteria
D) cyanobacteria, purple sulfur bacteria, and green sulfur bacteria
E) purple sulfur, purple non-sulfur, and green sulfur bacteria

Question 34

The pyruvate dehydrogenase reaction catalyzes the oxidation and decarboxylation of pyruvate into which of these products?

A) an acetyl group + CO₂.
B) lactic acid
C) citrate
D) ethanol + CO₂
E) acetic acid and CO₂

Question 35

The purple sulfur bacteria produce reducing power during the light reactions of photosynthesis by what process?

A) cyclic photophosphorylation
B) the Calvin cycle
C) reverse electron flow
D) the reverse TCA cycle
E) the Parnas pathway

Question 36

Which statement is TRUE with respect to the electron transport system?

A) The electron transport system accepts electrons directly from glucose.
B) In bacteria, the electron transport system is located in the cytoplasm.
C) A proton motive force is generated as electrons move through the system to a terminal acceptor.
D) In prokaryotes, protons are transported into the cell as electrons move through the system.
E) ATP is produced by a process called substrate-level phosphorylation.

Question 37

When does feedback inhibition of an enzyme occur?

A) If an end product of the pathway binds to the allosteric site of the enzyme.
B) If a competitive inhibitor binds to the active site of the enzyme.
C) If the coenzyme fails to bind to the active site of the enzyme.
D) If an end product of the pathway binds to the active site of the enzyme.
E) If a noncompetitive inhibitor binds to the active site of the enzyme.

Question 38

How is ATP generated during the light-dependent reactions of photosynthesis?

A) Substrate-level phosphorylation.
B) A proton motive force driven ATP synthase.
C) Electron driven NADPH synthase.
D) Carbon dioxide fixation.
E) Chlorophyll a.

Question 39

Where is the reaction center of photosystems located?

A) In the cytoplasm.
B) In the periplasmic space.
C) Within a biological membrane.
D) Either in the cytoplasm or within a membrane.
E) Within the cell wall.

Question 40

Chlorophyll a maximally absorbs light energy at what frequency(ies)?

A) 430 nm and 662 nm
B) 550 nm
C) 750 nm and 850 nm
D) 900 nm
E) 800 nm and 950 nm

Question 41

The only function of the Embden-Meyerhof pathway is the catabolism of glucose.

Question 42

A chemical that receives electrons during an oxidation/reduction reaction is being oxidized.

Question 43

How many ATP molecules is required to "fix" a molecule of nitrogen?

A) one
B) two
C) four
D) eight
E) sixteen

Question 44

What is denitrification?

A) The reduction of nitrate to dinitrogen.
B) The production of nitrate from ammonia.
C) The reduction of dinitrogen to nitrate.
D) The assimilation of nitrate by the cell.
E) The assimilation of ammonia by the cell.

Question 45

An organism that uses light as an energy source is called an autotroph.

Question 46

ATP molecules are the primary energy molecules for all cells.

Question 47

Nitrogen fixation is the reduction of _______ to ammonia for cell use.

A) nitrate
B) nitrite
C) hydroxylamine
D) dinitrogen
E) nitric oxide

Question 48

The biosynthesis of amino acids requires starting intermediates from which of these pathways?

A) glycolysisonly
B) the TCA cycleonly
C) glycolysis and TCA cycle
D) the pentose phosphate pathway and glycolysis
E) glycolysis, TCA cycle, and the pentose phosphate pathway

Question 49

Which amino acids are the primary nitrogen donors for biosynthetic reactions in the cell?

A) glycine and glutamate
B) glycine and serine
C) glutamine and glutamate
D) glutamine and serine
E) serine and glutamate

Question 50

A net gain of four ATP are produced during glycolysis from the conversion of a single glucose to two pyruvate molecules during the Embden- Meyerhof pathway.

Question 51

How would the "dark reactions" of photosynthesis best be described?

A) energy generating reactions
B) carbon dioxide fixing reactions
C) glycolytic reactions
D) reducing power generating reactions
E) part of photosystem II

Question 52

The key carbon dioxide fixation reaction in the Calvin Cycle is carried out by which enzyme?

A) ribulose 1,5-bisphosphate carboxylase
B) ribulose 1,5-bisphosphate kinase
C) ribose 1,5-bisphosphate carboxylase
D) ribose 1,5-bisphosphate kinase
E) ribose 1,5-bisphosphate transcarboxylase

Question 53

A reaction that has a negative ΔG°' is exergonic.

Question 54

Which nitrogen species is most readily incorporated into an organic molecule in the cell?

A) dinitrogen
B) nitrate
C) nitrite
D) ammonia
E) nitric oxide

Question 55

During glycolysis,the transfer of phosphate from phosphoenolpyruvate to ADP is an example of substrate-level phosphorylation.

Question 56

What is dissimulative nitrate reduction?

A) The production of nitrate from ammonia.
B) The incorporation of nitrate into cellular material.
C) Anaerobic reduction of nitrate.
D) Nitrogen fixation.
E) The production of nitrate from nitrite.

Question 57

The most common lipids in the cell are synthesized from ___________ and ____________.

A) fatty acids and sterol
B) fatty acids and glycerol
C) fatty acids and hopanoids
D) hopanoids and sterols
E) glycerol and hopanoids

Question 58

Which of these best describes assimilatory sulfate reduction?

A) The reduction of sulfate to elemental sulfur.
B) The reduction of sulfate for incorporation into cellular material.
C) The reduction of sulfate to sulfide for excretion by the cell.
D) A type of anaerobic respiration.
E) An energy yielding process.

Question 59

For what purpose is the reductive TCA cycle used by the green sulfur bacteria?

A) carbon dioxide fixation
B) generation of reducing power
C) glucose breakdown
D) energy generation
E) respiration

Question 60

The process of oxidative phosphorylation involves an electron transport chain.

Question 61

Enzymes increase the rate of a biochemical reaction by lowering the _________ _________ of the reaction.

Question 62

Anaerobic respiration is the same metabolic process as fermentation.

Question 63

The final product of the light reaction of photosynthesis is glucose.

Question 64

Most of the electrons that are donated to the electron transport chain by intermediate electron carriers are derived from oxidation/reduction reactions in glycolysis.

Question 65

Metabolic processes in the cell that yield energy are called ____________.

Question 66

Some enzymes are able to exist and remain active outside the cell.

Question 67

During the respiratory process,as electrons are passed through the electron transport chain,a ________ ________ force is generated across a biological membrane to drive the synthesis of ATP by a membrane associated ATP synthase.

Question 68

The assimilation of sulfate requires energy.

Question 69

The β-oxidation pathway is used for the breakdown of nucleotides for use as carbon source.

Question 70

The use of an exogenous terminal electron acceptor other than oxygen is called __________ __________.

Question 71

Organism that use inorganic molecules as electron sources are called ______________.

Question 72

The most common carbon dioxide fixation pathway used by cyanobacteria is the Calvin cycle.

Question 73

Most cells prefer to assimilate nitrogen as ammonia.

Question 74

The pentose phosphate pathway is important for producing the intermediate ribose-5-phosphate for the synthesis of __________________.

Question 75

Fermentation reactions reoxidize NADH.

Question 76

The starting intermediate for the synthesis of the amino acid glutamate is α-ketoglutarate.

Question 77

Organism that use light as energy sources are called _____________.

Question 78

Energy production by chemolithotrophs result of inorganic molecule oxidation and passage of electrons into an electron transport chain for the generation of a proton motive force to drive an ATPase for the synthesis of ATP.

Question 79

ATP that is produce directly from a biochemical reaction in the cell as the result of a phosphate transfer to ADP is called ____________ phosphorylation.

Question 80

Oxygen is produced by all photosynthetic microorganisms.