Deck 6: Metabolism: Fueling Cell Growth

Question 1

Cells degrade sugar largely to

A)gain energy.
B)use energy.
C)convert fat to energy.
D)utilize coenzymes.

Answer 1

gain energy.

Question 2

Glycolysis

A)is also known as the Embden-Meyerhof-Parnas pathway.
B)is also known as the Entner-Duodoroff pathway.
C)is used by Pseudomonas and a few other bacteria.
D)generates some energy and NADPH.
E)is also known as the Entner-Duodoroff pathway AND is used by Pseudomonas and a few other bacteria.

Answer 2

is also known as the Embden-Meyerhof-Parnas pathway.

Question 3

Oxygen serves as the terminal electron acceptor in

A)fermentation.
B)aerobic respiration.
C)anaerobic respiration.
D)reduction.

Answer 3

aerobic respiration.

Question 4

Exergonic reactions

A)occur when there is more free energy in the products than the reactants.
B)occur when there is more free energy in the reactants than the products.
C)are defined as a decrease in entropy.
D)are chemoorganotrophic.

Question 5

The most common starting pathway for the breakdown of sugars is

A)respiration.
B)fermentation.
C)glycolysis.
D)oxidation.

Question 6

Each of the following statements about chemoorganotrophs is true EXCEPT:

A)They may use substrate-level phosphorylation to produce ATP.
B)They may use oxidative phosphorylation to produce ATP.
C)They may use photophosphorylation to produce ATP.
D)They utilize an electrochemical gradient.

Question 7

Biosynthetic reactions that require energy for the conversion of molecular subunits into larger molecules are called

A)kinetic energy.
B)catabolic reactions.
C)precursor molecules.
D)anabolic reactions.

Question 8

Glycolysis,the Entner-Duodoroff pathway and the pentose phosphate pathway all produce

A)pyruvate.
B)NAD.
C)NADP.
D)acetyl-CoA.

Question 9

Concerning catabolism and anabolism,

A)they refer to reactions solely dealing with the metabolism of lipids.
B)the intermediates of one serve as the reactants in the other.
C)the energy gathered in one is utilized in the other.
D)they refer solely to the reactions involved in synthesis of carbohydrates.
E)the intermediates of one serve as the reactants in the other AND the energy gathered in one is utilized in the other.

Question 10

The name given to the reaction involving addition of electrons or hydrogen atoms to a compound is termed

A)glycolysis.
B)reduction.
C)oxidation.
D)metabolism.

Question 11

The readily usable energy currency of cells is

A)electricity.
B)the electron transport system.
C)ATP.
D)CTP.
E)the electron transport system AND CTP.

Question 12

The terminal electron acceptor in respiration may be

A)oxygen.
B)nitrate.
C)NAD.
D)an inorganic molecule.
E)oxygen,nitrate,AND an inorganic molecule.

Question 13

The general term used to describe the anabolic and catabolic reactions in a cell is

A)enzymatic.
B)thematic.
C)aerobic respiration.
D)metabolism.

Question 14

Energy is defined as

A)water flowing up a dam.
B)the capacity to do work.
C)the use of high-level phosphate bonds.
D)the potential to fall.

Question 15

Studies done by Buchner showed that ground-up yeast cells were able to convert sugar to alcohol.The components of the mixture that were responsible for this transformation were

A)DNA molecules.
B)enzymes.
C)lipids.
D)carbohydrates.

Question 16

NAD in its reduced form is abbreviated as

A)NADH.
B)NAD.
C)NAD^-.
D)NADP.

Question 17

Bacteria that can absorb light energy and convert it into ATP are commonly called

A)cytochromes.
B)lysosomes.
C)chemotrophs.
D)phototrophs.
E)cytochromes AND chemotrophs.

Question 18

The name given to the reaction involving removal of electrons or hydrogen atoms from a compound is termed

A)glycolysis.
B)reduction.
C)oxidation.
D)metabolism.

Question 19

Free energy

A)includes the energy lost as heat.
B)is the amount of energy gained by breaking bonds of a chemical.
C)differs for a given reaction depending on the number of steps involved.
D)always results in a decrease in total energy.
E)is the amount of energy gained by breaking bonds of a chemical AND differs for a given reaction depending on the number of steps involved.

Question 20

Experiments designed by ______________ suggested that living cells caused the fermentation of sugar to produce alcohol.

A)Pasteur
B)Koch
C)Wohler
D)Fleming

Question 21

Most enzymes function best at

A)acidic pH and high salt concentrations.
B)basic pH and low salt concentrations.
C)neutral pH and high salt concentrations.
D)slightly above pH 7 and low salt concentrations.

Question 22

Most enzymes

A)are generic,typically recognizing a number of different substrates.
B)are specific,typically recognizing a single or a few substrates.
C)are active over a wide pH range.
D)are active over a wide temperature range.
E)are generic,typically recognizing a number of different substrates AND are active over a wide pH range.

Question 23

Environmental factors that may affect enzyme activity include

A)temperature.
B)pH.
C)salt.
D)temperature,pH,AND salt.

Question 24

Allosteric enzymes

A)may bind two substrates.
B)are used to bind to other enzymes.
C)have an additional binding site that is involved in regulating enzyme activity.
D)are twice as fast as single-site enzymes.
E)may bind two substrates AND are twice as fast as single-site enzymes.

Question 25

Which is/are true regarding organic acids?

A)They are weak acids.
B)They are often involved in metabolic reactions.
C)They often exist in the ionized form at the near-neutral pH found in a cell.
D)Pyruvate and pyruvic acid refer to different forms of the same substance.
E)All of the choices are true.

Question 26

Enzymes speed up reactions by

A)raising activation energy.
B)producing heat.
C)reducing entropy.
D)lowering activation energy.
E)raising activation energy AND reducing entropy.

Question 27

Coenzymes are derivatives of

A)minerals.
B)proteins.
C)lipids.
D)vitamins.

Question 28

Enzymes act on _______ to generate ________.

A)Products,catabolites
B)Substrates,products
C)Products,substrates
D)Glucose,anabolites

Question 29

Pyruvate can be metabolized along two major routes.They are

A)oxidation and reduction.
B)fermentation and respiration.
C)metabolism and anabolism.
D)anabolism and catabolism.

Question 30

Enzymes act as

A)substrates.
B)catalysts.
C)products.
D)catabolites.

Question 31

The mutual interaction of substrate and enzyme is described as a(n)

A)lock and key arrangement.
B)induced fit.
C)active site.
D)allosteric site.
E)active site AND allosteric site.

Question 32

The use of the suffix "ase" on a word denotes a(n)

A)substrate.
B)product.
C)enzyme.
D)electron acceptor.
E)substrate AND electron acceptor.

Question 33

Fermentation

A)uses an inorganic molecule as the final electron acceptor.
B)uses an organic molecule as the final electron acceptor.
C)results in the production of a large amount of ATP.
D)is necessary in some organisms to produce reduced electron carriers.
E)uses an organic molecule as the final electron acceptor AND is necessary in some organisms to produce reduced electron carriers.

Question 34

Which is/are true of coenzymes?

A)They are organic molecules.
B)They transfer atoms from one molecule to another.
C)They may bind to a number of different enzymes.
D)They are synthesized from vitamins.
E)All of the choices are correct.

Question 35

The small,non-protein molecules that can be readily separated from an enzyme and are responsible for transfer of atoms from one molecule to another are referred to as

A)vitamins.
B)enzymes.
C)hormones.
D)coenzymes.

Question 36

Mercury in mercurochrome inhibits growth

A)through competitive inhibition.
B)through a reversible action.
C)by oxidizing the sulfhydryl groups in cysteine.
D)by changing the shape of proteins.
E)by oxidizing the sulfhydryl groups in cysteine AND by changing the shape of proteins.

Question 37

Feedback inhibition

A)is a means of regulating the amount of product produced.
B)often involves the use of allosteric enzymes.
C)involves inhibiting the last of a series of reactions.
D)results in raising the activation energy for the reaction.
E)is a means of regulating the amount of product produced AND often involves the use of allosteric enzymes.

Question 38

The term "precursor metabolite" refers to molecules that

A)activate cell components.
B)are used in biosynthesis.
C)result from cell activities.
D)are present but inactive.

Question 39

Which is true of competitive inhibition?

A)It involves an allosteric enzyme.
B)Substrate and inhibitor both bind to the active site.
C)A sulfa antibiotic is a competitive inhibitor.
D)Mercury is a competitive inhibitor.
E)Substrate and inhibitor both bind to the active site AND a sulfa antibiotic is a competitive inhibitor.

Question 40

Which of the following processes generates the greatest amount of energy?

A)Fermentation
B)Aerobic respiration
C)The Entner-Duodoroff pathway
D)Glycolysis
E)Fermentation AND the Entner-Duodoroff pathway

Question 41

The transition step

A)links glycolysis to the pentose phosphate pathway.
B)links the pentose phosphate pathway to the Entner-Duodoroff pathway.
C)links glycolysis to the TCA cycle.
D)takes place in the matrix of the nucleus.

Question 42

The electron transport system

A)requires a membrane.
B)utilizes the nuclear membrane of eukaryotes.
C)utilizes the mitochondrial membrane of prokaryotes.
D)generates a concentration gradient of protons.
E)requires a membrane AND generates a concentration gradient of protons.

Question 43

In the electron transport system

A)NADH and FADH₂ both donate electrons at the same location.
B)NADH donates electrons "upstream" of where FADH₂ donates electrons.
C)NAD donates electrons at the head of the chain.
D)NADP donates electrons in the middle of the chain.

Question 44

The TCA cycle must "turn twice" in order to complete the oxidation of one glucose molecule.

Question 45

The terminal electron acceptor in aerobic respiration is water,which is broken down to hydrogen and oxygen.

Question 46

What happens to the carbon molecules in the pyruvic acid that goes through the TCA cycle?

A)They get incorporated into cell material.
B)They are excreted as waste organic acids.
C)They become carbon dioxide.
D)They form "energy storage molecules" and are stored by the cell.

Question 47

The change in free energy of a reaction varies.

Question 48

The energy yield of any energy-transforming pathway

A)is fixed.
B)is variable depending on the type of enzymes used.
C)is variable depending on the amount of precursor metabolites removed for biosynthesis.
D)is fixed by the amount of oxygen available.

Question 49

Anoxygenic photosynthetic bacteria

A)obtain electrons from water.
B)do not produce oxygen as a by-product.
C)may obtain electrons from H₂S.
D)are obligate aerobes.
E)do not produce oxygen as a by-product AND may obtain electrons from H₂S.

Question 50

The production of ATP via the electron transport system,in either eukaryotes or prokaryotes,requires the use of a membrane.

Question 51

Which is true regarding the three central metabolic pathways?

A)They form high-energy bonds that can be used to synthesize ATP.
B)They form intermediates that can be oxidized to generate reducing power.
C)They form precursor metabolites.
D)All of the choices are correct.

Question 52

In the phototrophic production of energy,the oxygen originates from

A)carbon dioxide.
B)water.
C)glucose.
D)hydrogen peroxide.

Question 53

The sugar component of RNA and DNA nucleotides are synthesized

A)as deoxyribose and then changed to ribose.
B)as ribose and then changed to deoxyribose.
C)separately.
D)using the Calvin cycle.
E)as deoxyribose and then changed to ribose AND using the Calvin cycle.

Question 54

The TCA cycle produces

A)ATP through substrate-level phosphorylation.
B)NADH.
C)FADH₂.
D)precursor metabolites.
E)All of the choices are correct.

Question 55

Enzymes are changed by the reaction as they raise the activation energy.

Question 56

Proton motive force

A)is used to synthesize ATP.
B)is used to drive flagella rotation.
C)is used to produce NADH.
D)is used to produce FADH₂.
E)is used to synthesize ATP AND is used to drive flagella rotation.

Question 57

Both glycolysis and the pentose phosphate pathway oxidize glucose to pyruvate.

Question 58

Competitive inhibition usually involves both substrate and inhibitor competing for binding at the allosteric site.

Question 59

Glycolysis

A)requires oxygen.
B)produces 3 ATP molecules per molecule glucose.
C)produces 4 molecules of NAD per molecule glucose.
D)may occur under aerobic or anaerobic conditions.
E)produces 3 ATP molecules AND produces 4 molecules of NAD per molecule glucose.

Question 60

Which type of phosphorylation does not require a membrane?

A)Substrate-level phosphorylation
B)Oxidative phosphorylation
C)Photophosphorylation
D)All types of phosphorylation require a membrane.

Question 61

Why would a cell ferment rather than respire?

A)There's no oxygen present,and it cannot respire anaerobically.
B)It lacks the ability to respire (i.e.no electron transport chain).
C)There is no oxygen present and it cannot use anaerobic respiration OR it lacks the ability to respire (i.e.,no electron transport chain).
D)None of the above.

Question 62

How would cellulose-degrading bacteria in the rumen (stomachs)of a cow benefit the animal?

A)The bacteria would produce,secrete,and incorporate organic molecules as they obtain energy from the cellulose in grass and replicate.The cow could then digest both the secreted organic molecules AND the bacteria that synthesized them.
B)The bacteria would produce sugars as they digested the cellulose.These sugars would be given off to the cow as a symbiotic relationship in exchange for the protected location of the stomachs of the cow for the bacteria to grow and replicate in.
C)They wouldn't benefit the animal-they would replicate and cause disease in the animal,leading to its death.
D)They wouldn't benefit the animal-only the bacteria within the animal.This is why cows must have food sources other than grass in order to survive.

Question 63

H₂S and NH₃ may be used by some prokaryotes as energy sources.

Question 64

Fermentation is sometimes used as a means of slowing food spoilage.Why would fermentation lead tothis outcome?

A)Fermentation is THE process that directly reduces sugars in food.Without sugars,bacteria cannot grow and spoil the food.
B)Fermentation will lead to production of high levels of ethanol (95% or higher!)-ethanol will kill bacteria.
C)Fermentation will lead to production of acidic by-products,dropping the pH of the food below a level that bacteria can tolerate.
D)This is a trick question-fermentation actually IS food spoilage and cannot be used to prevent it under any circumstances.

Question 65

In fermentation,the only ATP produced was during glycolysis and the fermentation reactions usually result in converting NADH to NAD.

Question 66

The Calvin cycle produces six ATP for every six turns of the cycle.

Question 67

A student argued that aerobic and anaerobic respiration should produce the same amount of energy.He argued that both processes are essentially the same-only the terminal electron acceptor is different.What's wrong with his argument?

A)Nothing-they SHOULD both produce the same amount of energy.Clearly he knows more than his professors or the writers of his textbook.
B)Not all electrons are brought into the electron transport chain with the same amounts of potential energy.NADH,for example,enters the electron transport chain "further up" than FADH₂-so it will lead to less proton motive force being generated,and thus less eventual ATP.
C)Not all electron acceptors are the same-some are closer in terms of electronegativity to their high-energy electron carrier molecules (e.g.,NADH)than others.The amount of energy that can eventually be obtained is directly proportional to the degree of difference in electronegativity between the high-energy electron carrier and the eventual terminal electron acceptor.The greater the difference,the greater the energy obtained.Oxygen typically has the highest electron affinity of the terminal electron acceptors utilized.
D)He should believe what his instructors tell him,without question-and they say aerobic respiration is better,so it MUST be so.

Question 68

Chemolithotrophs near hydrothermal vents support a variety of life forms.Why is this analogous to photosynthetic microbes supporting life forms closer to the surface of the planet?

A)Because all life forms need some energy source,electron source,and carbon source.Chemolithotrophs fix inorganic carbon and,if consumed by other microbes,could serve as sources for all three requirements for life.This is very similar to the role that photosynthetic microbes play in the top levels of the oceans/lakes.
B)Because chemolithotrophs will also utilize energy from sunlight to form their sugars/get their chemical energy...much like photosynthetic microbes.
C)Because chemolithotrophs also pull in carbon dioxide as their carbon source,just like photosynthetic microbes.
D)Because photosynthetic microbes utilize heat energy from the sun as an energy source.Chemolithotrophs utilize heat energy from hydrothermal vents,but it's still heat energy.This makes both microbes similar.

Question 69

A worker in a cheese-making facility argued that whey,a nutrient-rich by-product of the process,should be dumped into a nearby pond to serve as fish food.Is this a good idea or a bad one,and why?

A)It's a great idea! Let's feed the fish and help them multiply!
B)Bad idea-the fish won't be able to eat the whey,so it will sit there rotting and pollute the waters,making them uninhabitable for the fish.
C)Bad idea-bacteria would thrive on this rich nutrient source and multiply readily.As they multiply,they'll use the oxygen in the water to harvest the energy from the whey,depleting it.As the oxygen depletes below a certain point,the fish (and perhaps other organisms)will not be able to survive.
D)Great idea! This will not only feed the fish,but also microbes and other small organisms.It'll enhance the entire food chain and help all of them!