Deck 3: Cell Metabolism

Question 1

A substrate is the same as a

A)reactant.
B)ligand.
C)product.
D)liquid.
E)solute.

Answer 1

A

Question 2

In the chemical equation A + B "C + D, the arrow indicates that the reaction is

A)the net reaction of A+B.
B)a metabolic pathway.
C)bidirectional.
D)unidirectional.
E)None of the answers is correct.

Answer 2

C

Question 3

For each FADH2 that supplies electrons to the electron transport system, _ ATP(s)is/are synthesized. For each NADH + H+ that supplies electrons to the electron transport system, ATP(s)is/are synthesized.

A)2 : 3
B)3 : 2
C)1 : 2
D)1 : 1
E)2 : 1

Answer 3

A

Question 4

Which of the following statements about end- product inhibition is FALSE?

A)The last product of a metabolic pathway inhibits the activity of an enzyme earlier in that path.
B)The enzyme modulated is often the rate- limiting enzyme.
C)It is an example of negative feedback.
D)It usually involves allosteric modulation of an enzyme.
E)The amount of product produced is increased by this process.

Question 5

Gluconeogenesis refers to synthesis of and occurs in .

A)glucose : the liver
B)triglycerides : adipose tissue
C)glucose : all organs
D)glycogen : the liver
E)fatty acids : adipose tissue

Question 6

Where within the cell does the electron transport chain occur?

A)nucleus
B)inner mitochondrial membrane
C)mitochondrial matrix
D)rough ER
E)cytosol

Question 7

What is the strength of binding between an enzyme and substrate called?

A)peptide bond
B)covalent modulator
C)affinity
D)enzyme- substrate complex
E)ligand

Question 8

In terms of energy production, the Krebs cycle is significant because it

A)reduces the coenzymes NAD and FAD for oxidative phosphorylation.
B)provides acetylcoenzyme A for glucose synthesis.
C)breaks down glucose.
D)directly produces large amounts of ATP.
E)produces acetylcoenzyme A for fatty acid synthesis.

Question 9

Enzymes are what class of molecule?

A)trace metals
B)nucleic acids
C)lipids
D)proteins
E)carbohydrates

Question 10

Which of the following is TRUE of an endergonic reaction?

A)Endergonic reactions never occur.
B)The change in energy of the reaction is positive.
C)The reaction proceeds spontaneously.
D)The only product of the reaction is heat.
E)The only product of the reaction is water.

Question 11

The measure of how many product molecules can be produced by an enzyme per unit of time is referred to as that enzyme's

A)cofactor rate.
B)specificity.
C)catalytic rate.
D)coenzyme rate.
E)affinity.

Question 12

In allosteric regulation, the modulator molecule binds to the

A)cofactor by weak, reversible interactions.
B)catalytic site of the enzyme by weak, reversible interactions.
C)regulatory site of the enzyme by weak, reversible interactions.
D)regulatory site by covalent bonds.
E)catalytic site by covalent bonds.

Question 13

In the presence of a limited oxygen supply, pyruvate is converted to what?

A)NADH
B)lactate
C)ATP
D)glucose
E)acetyl CoA

Question 14

Chemical reactions that involve the formation of peptide bonds between amino acids that produce water as a byproduct are called _ _ reactions.

A)hydrolysis
B)phosphorylation
C)reduction
D)oxidation
E)condensation

Question 15

The complete oxidation of glucose releases how many kcal of energy for every mole of glucose?

A)420
B)266
C)98
D)686
E)7

Question 16

If the energy change of a reaction (OE)is positive, then

A)the reactants had more energy than the products.
B)the products had more energy than reactants.
C)no energy was added to the reaction.
D)the reactants had the same energy as the products.
E)energy has been released as a byproduct.

Question 17

ATP synthase is able to use the potential energy that originates from to produce ATP.

A)complex IV
B)the hydrogen gradient across the inner mitochondrial membrane
C)complex I
D)the sodium gradient across the inner mitochondrial membrane
E)the phosphorylation of cytochromes

Question 18

The rate at which an enzyme- catalyzed reaction occurs can be increased by

A)decreasing substrate concentration.
B)changing the enzyme's conformation, thereby reducing its affinity for the substrate.
C)decreasing temperature.
D)increasing enzyme concentration.
E)releasing the cofactor that was bound to the enzyme.

Question 19

Glucose is stored in the form of glycogen primarily within what two organs?

A)pancreas and small intestine
B)stomach and small intestine
C)liver and pancreas
D)small and large intestine
E)skeletal muscles and liver

Question 20

As the energy required to overcome the activation energy barrier increases, the reaction rate will

A)remain unaltered.
B)depend solely upon temperature.
C)decrease.
D)occur more frequently.
E)increase.

Question 21

What is the major physiological importance of breathing?

A)Oxygen must be present in our cells to break down food into energy.
B)It eventually produces water, which we need to survive.
C)We need to eliminate CO2 from our system because it is a waste product.
D)We need to control our core temperature by breathing in oxygen from the environment.
E)We need oxygen to survive.

Question 22

Chemical reactions that involve the production of a phosphate bond are called reactions.

A)dephosphorylation
B)reduction
C)condensation
D)oxidation
E)phosphorylation

Question 23

The sum of the thousands of chemical reactions that occur within the body is called

A)hydrolysis.
B)oxidation.
C)reduction.
D)phosphorylation.
E)metabolism.

Question 24

When phosphate is added to ADP to form the energy- storing molecule ATP, this is known as and, since water is also produced, this reaction is also considered a reaction.

A)phosphorylation : dephosphorylation
B)dephosphorylation : condensation
C)phosphorylation : condensation
D)dephosphorylation : hydrolysis
E)phosphorylation : hydrolysis

Question 25

Refer to Scenario 3.1. How could niacin supplementation have helped Tony during the race?

A)Niacin is an important protein found in muscle cells.
B)High concentrations of niacin in the system can cause vomiting, which is good for you before a long race as it helps you lose weight.
C)Niacin is an important coenzyme known as nicotinamide adenine dinucleotide or NAD, a derivative of vitamin B3, which is a necessary energy- storing molecule required to produce the maximum amount of ATP's possible from glucose metabolism.
D)Niacin is a B vitamin, and B vitamins are cofactors which help give enzymes their shape, and therefore, allow reactions in the body to be carried out at a much faster rate.
E)None of the answers is correct.

Question 26

What is the net energy yield for the anaerobic metabolism of one glucose molecule?

A)two molecules of ATP and 0 NADH
B)two molecules of ATP and three NADH
C)two molecules of ATP and two NADH
D)two molecules of NADH and 0 ATP
E)36 molecules of ATP and 0 NADH

Question 27

How many ATP are produced for each acetyl coenzyme A completely catabolized in the presence of oxygen?

A)2
B)6
C)10
D)3
E)12

Question 28

Identify the following chemical reaction by its type: Monounsaturated fatty acid + 2H -Saturated fatty acid.

A)condensation
B)hydrolysis
C)oxidation
D)phosphorylation
E)reduction

Question 29

Identify the following chemical reaction by its type: Protein + Phosphate -Protein - Phosphate.

A)oxidation
B)condensation
C)hydrolysis
D)phosphorylation
E)reduction

Question 30

Making or synthesizing a protein would be considered a(n)reaction and the type of reaction that carries this process out is a _ reaction.

A)metabolic : hydrolysis
B)catabolic : condensation
C)anabolic : hydrolysis
D)anabolic : condensation
E)catabolic : hydrolysis

Question 31

ATP is synthesized by substrate- level phosphorylation during which of the following?

A)glycolysis only
B)conversion of pyruvate to lactate only
C)Krebs cycle only
D)glycolysis and the Krebs cycle only
E)glycolysis, the Krebs cycle, and during conversion of pyruvate to lactate

Question 32

Each time an electron is passed between the molecules of the electron transport chain,

A)energy is gained.
B)oxygen accepts the electrons.
C)energy is released.
D)carbon dioxide is produced.
E)an ATP molecule is produced.

Question 33

The greater the attractive forces between substrate and enzyme, that enzyme is said to have a higher for the substrate.

A)affinity
B)coenzyme activity
C)cofactor activity
D)repulsion
E)catalytic rate

Question 34

For each acetyl CoA that enters the Krebs cycle, NAD(s)are reduced, FAD(s)are reduced, and ATP are synthesized by substrate- level phosphorylation.

A)1 : 1 : 1
B)3 : 1 : 1
C)1 : 2 : 3
D)1 : 1 : 3
E)2 : 2 : 2

Question 35

Start with the following chemical reaction at equilibrium: A -B. If you add product B to the system from a separate pathway, then what change in the reaction occurs?

A)Because the reaction is at equilibrium, there will be no change in rates of either the forward or reverse reaction.
B)Because the reaction is at equilibrium, the rates of both the forward and reverse reactions increase.
C)The rate of the forward reaction increases.
D)The rate of the reverse reaction increases.
E)The rate of the forward and reverse reactions both decrease.

Question 36

How do enzymes speed up chemical reactions?

A)by lowering the temperature, thereby reducing friction
B)by making sure the enzyme is part of the product
C)by lowering the activation energy barrier
D)by converting kinetic energy back to potential energy
E)by increasing the activation energy barrier

Question 37

During what type of reaction are electrons removed from the reactant?

A)reduction
B)oxidation
C)phosphorylation
D)electrocution
E)None of the answers is correct.

Question 38

Where does beta- oxidation of fatty acids occur?

A)peroxisome
B)mitochondrial intermembrane space
C)smooth endoplasmic reticulum
D)mitochondrial matrix
E)cytosol

Question 39

Which of the following statements about chemical equilibrium is FALSE?

A)At equilibrium, the concentration of products equals the concentration of reactants.
B)At equilibrium, the rate of formation of products equals the rate of formation of reactants.
C)Adding an enzyme will not alter the equilibrium.
D)Increasing the amount of reactant will increase the production of product.
E)Decreasing the amount of product will increase the production of product.

Question 40

In skeletal muscle, ATP can be synthesized by transferring a phosphate group from creatine- P to ADP to form ATP and creatine. In this example, ATP was synthesized by what process?

A)oxidation
B)substrate- level phosphorylation
C)reduction
D)oxidative phosphorylation
E)condensation

Question 41

In the presence of oxygen, the process of glycolysis produces which of the following products?

A)2 glycerol
B)2 lactate
C)1 lactate
D)1 pyruvate
E)2 pyruvate

Question 42

A-OH + H-B -A-B + H2O describes what type of reaction?

A)hydrolysis
B)reduction
C)oxidation
D)phosphorylation
E)condensation

Question 43

Identify the following chemical reaction by its type: FAD + 2H -FADH2.

A)phosphorylation
B)oxidation
C)reduction
D)condensation
E)hydrolysis

Question 44

Which of the following statements best represents the second law of thermodynamics?

A)Stored energy can eventually be converted to kinetic energy.
B)Energy is neither created nor destroyed.
C)Energy is the capacity to do work.
D)Natural processes tend to proceed in the direction that expands the energy.
E)Metabolic reactions are the sum of all the reactions in the body.

Question 45

What is glycogenolysis?

A)the breakdown of glycogen to glucose
B)a form of gluconeogenesis
C)the synthesis of membrane carbohydrates
D)the synthesis of glycogen from glucose
E)the breakdown of glycoproteins

Question 46

What chemical group is most commonly added to a protein during covalent regulation?

A)amine
B)phosphate
C)kinase
D)nitrate
E)carboxyl

Question 47

A=B + 2H -HA-BH is an example of what type of reaction?

A)hydrolysis
B)condensation
C)oxidation
D)reduction
E)phosphorylation

Question 48

Identify the following chemical reaction by its type: Protein + H2O -Amino acids.

A)reduction
B)phosphorylation
C)oxidation
D)condensation
E)hydrolysis

Question 49

What is the first component of the electron transport chain that accepts electrons from an FADH2 molecule?

A)coenzyme Q
B)cytochrome b
C)flavin adenine dinucleotide
D)cytochrome a3
E)flavin mononucleotide

Question 50

When a substrate binds to a protein via weak interactions, the substrate is referred to as a

A)ligand.
B)modulator.
C)reactant.
D)peptide bond.
E)product.

Question 51

In a metabolic pathway, the enzyme working the slowest in that pathway is known as the enzyme.

A)modulating
B)allosteric regulating
C)inhibitor
D)binding
E)rate- limiting

Question 52

In the induced- fit model for enzyme activity, the substrate alters the _ _ of the site on the enzyme.

A)shape : allosteric
B)conformation : inactive
C)conformation : allosteric
D)activity : active
E)conformation : active

Question 53

The energy that is stored within an object for later use is referred to as energy.

A)thermal
B)kinetic
C)potential
D)radiant
E)kinesthetic

Question 54

C6H12O6 + 6O2 -6CO2 + 6H2O is an example of what type of reaction?

A)phosphorylation
B)hydrolysis
C)oxidation
D)reduction
E)condensation

Question 55

HA-BH -A=B + 2H is an example of what type of reaction?

A)hydrolysis
B)condensation
C)reduction
D)phosphorylation
E)oxidation

Question 56

Which of the following molecules is NOT converted to glucose through the process of gluconeogenesis?

A)pyruvate
B)amino acids
C)glycerol
D)fatty acids
E)lactate

Question 57

Refer to Scenario 3.1. Tony was breathing heavily but still able to walk to the finish line. Why?

A)Even though he had used all of his energy, he was able to produce a small amount of ATP via gluconeogenesis. However, the effort to do so caused him to breathe heavily.
B)Tony was breathing heavily because he needed to release the heat generated through metabolism. Because he was overheated, he had to walk.
C)Tony was breathing heavily because he was trying to get enough oxygen to his tissues to start producing ATP again. He was able to walk because he still had enough oxygen getting to his brain to keep him conscious.
D)Tony was breathing heavily because he was trying to get enough oxygen to his tissues to start producing ATP again in large amounts. He was still able to walk because, even though he lacked oxygen at the end of his electron transport chain, he was still producing a small amount of ATP via glycolysis.
E)None of the answers is correct.

Question 58

What is the final acceptor of electrons in the electron transport?

A)water
B)pyruvate
C)glucose
D)carbon dioxide
E)oxygen

Question 59

Insulin levels in the blood are elevated in response to which of the following?

A)increased blood glucose levels
B)decreased blood triglycerides
C)decreased blood fatty acids
D)fasting for 12 hours
E)sleep

Question 60

Chemiosmotic coupling refers to

A)chemical coupling of each reaction within the mitochondria.
B)coupling of the Krebs cycle to the electron transport chain.
C)the transfer of a phosphate group from one molecule to another.
D)chemical coupling between substrate and enzymes.
E)the harnessing of energy from the reactions of the electron transport chain to make ATP.

Question 61

Identify the following chemical reaction by its type: C6H12O6 + 6 O2 -6 CO2 + 6 H2O.

A)condensation
B)oxidation
C)phosphorylation
D)reduction
E)hydrolysis

Question 62

In a reduction reaction, which of the following is most likely added to the reactants?

A)water
B)phosphate
C)oxygen
D)electrons
E)neutrons

Question 63

In this model of enzyme activity, both substrate and product can bind to the active site.

A)law of mass action
B)induced- fit
C)enzyme- substrate- complex
D)affinity
E)lock- and- key

Question 64

Many drugs are manufactured that tend to bind to an enzyme's active site more quickly than the substrate the enzyme normally binds. What quality allows the drug to be attracted to the active site more readily than the substrate?

A)competition
B)the lock- and- key model
C)chemical specificity
D)affinity
E)saturation

Question 65

If the graph of an enzyme- catalyzed reaction shows a sigmoidal relationship between substrate concentration and reaction rate, then what can be said about the reaction?

A)It is endergonic.
B)It is allosterically regulated.
C)It is covalently regulated.
D)It is exergonic.
E)It is part of an oxidation- reduction process.

Question 66

Cyanide is a deadly poison that attaches to cytochrome c oxidase, the last protein in the electron transport chain before the terminal electron acceptor. Based on your knowledge of the electron transport chain, which statement below best describes the action of cyanide on the body?

A)Cyanide blocks the terminal electron acceptor oxygen and therefore will halt the production of ATP. The majority of ATP is normally produced in the electron transport chain and without it the body will begin to only go through glycolysis and start producing lactic acid and will eventually shut down due to a lack of ATP to run the body and because of the buildup of acid in the system.
B)Cyanide does not allow the Krebs cycle to be completed by blocking acetyl CoA from entering this cycle. This action shuts down the entire process of cellular metabolism.
C)Cyanide blocks the terminal electron acceptor, oxygen, causing an accumulation of CO2 in the tissues from cellular metabolism, and poisons the system due to excess waste products.
D)Cyanide does not allow H+ ions to be pumped into the outer membrane of the mitochondria and, therefore, they are never able to go down their concentration gradient and produce ATP.
E)Cyanide prevents NADH and FADH2 from dropping off their electrons at the beginning of the electron transport chain by causing a backup of electrons in the Krebs cycle.

Question 67

Where within the cell does the conversion of pyruvate to acetyl CoA occur?

A)cytosol
B)rough ER
C)nucleus
D)inner mitochondrial membrane
E)mitochondrial matrix

Question 68

Most of our fat is stored in adipocytes in the form of . This fat can be broken down by a process called _ to and .

A)triglycerides : lipolysis : glycerol : 3 fatty acids
B)triglycerides : glycogenolysis : fatty acids : carbon
C)glycogen : catabolism : fatty acids : amino acids
D)triglycerides : gluconeogenesis : glycerol : amino acids
E)glycogen : anabolism : glycerol : fatty acids

Question 69

During end- product inhibition,

A)the product of the rate- limiting step of an enzyme- catalyzed reaction inhibits the rate- limiting enzyme via covalent regulation.
B)the product of the rate- limiting step of an enzyme- catalyzed reaction inhibits the rate- limiting enzyme via allosteric regulation.
C)the final product of an enzyme- catalyzed reaction inhibits the rate- limiting enzyme via allosteric regulation.
D)the final product of an enzyme- catalyzed reaction inhibits the rate- limiting enzyme via covalent regulation.
E)the initial substrate of an enzyme- catalyzed reaction inhibits the rate- limiting enzyme via allosteric regulation.

Question 70

Which of the following does NOT occur in mitochondria?

A)oxidative phosphorylation
B)consumption of oxygen
C)conversion of pyruvate to lactate
D)Krebs cycle
E)production of carbon dioxide

Question 71

Decreasing temperatures will the frequency of collisions between molecules, thereby the reaction rate.

A)increase : decreasing
B)not alter : not changing
C)decrease : decreasing
D)not alter : increasing
E)increase : increasing

Question 72

The addition of two hydrogens and two electrons to NAD+ is an example of what type of chemical reaction?

A)condensation
B)reduction
C)oxidation
D)phosphorylation
E)hydrolysis

Question 73

What process occurs within the inner mitochondrial membrane?

A)gluconeogenesis
B)glycogenesis
C)glycolysis
D)electron transport chain
E)Krebs cycle

Question 74

Reaction rates higher or lower than required by the body lead to disease states. How does the body regulate its metabolic needs?

A)Reaction rates are regulated to match the body's needs at a particular moment.
B)Product is produced faster than substrate.
C)Reactants and products are at equilibrium.
D)The control center maintains a constant temperature so reaction rates remain the same.
E)Reactions move in the forward direction to produce product.

Question 75

Identify the following chemical reaction by its type: ADP + Pi -ATP + H2O.

A)hydrolysis
B)oxidation
C)condensation
D)phosphorylation
E)reduction

Question 76

Glycogen in muscle is used to

A)convert glucose to amino acids.
B)both fuel muscle activity and maintain blood glucose.
C)convert glucose to fats.
D)contribute to the maintenance of blood glucose.
E)fuel the activity of that muscle exclusively.

Question 77

Proteins are broken down to amino acids by

A)protein synthesis.
B)beta oxidation.
C)gluconeogenesis.
D)proteolysis.
E)lipolysis.

Question 78

Which of the following contains glucose- 6- phosphatase?

A)brain
B)skeletal muscle
C)liver
D)heart
E)all organs in the body

Question 79

Under anaerobic conditions, what is pyruvate converted to and where does this occur?

A)acetyl coenzyme A in the cytosol
B)lactate in the cytosol
C)acetyl coenzyme A in the mitochondria
D)fatty acid in the cytosol
E)lactate in the mitochondria

Question 80

What is the function of glucose- 6- phosphatase?

A)catalyze removal of one phosphate group from glucose
B)catalyze addition of six phosphate groups to glucose
C)catalyze addition of one phosphate group to glucose
D)catalyze removal of six phosphate groups from glucose
E)catalyze the removal of the phosphate group from glucose and add it to ADP to form ATP by substrate- level phosphorylation