Deck 7: Energy and Metabolism

Question 1

The life and death of cells are governed by:

A) the laws of thermodynamics.
B) only the first law of thermodynamics.
C) only the second law of thermodynamics.
D) only the third law of thermodynamics.
E) the laws of dynamic equilibrium.

Answer 1

A

Question 2

Which of the following accurately represents the relationship between the terms anabolism, catabolism, and metabolism?

A) anabolism = catabolism
B) metabolism = catabolism
C) catabolism = anabolism + metabolism
D) anabolism = catabolism + metabolism
E) metabolism = catabolism + anabolism

Answer 2

E

Question 3

An organism can exchange matter and energy with its surroundings.Thus, any change in an organism's energy content must be balanced by a corresponding change in the energy content of the surroundings.As such, an organism is referred to as:

A) a closed system.
B) an open system.
C) a dynamic system.
D) a thermally reactive system.
E) a potential system.

Answer 3

B

Question 4

When the free energy of the reactants is greater than the free energy of the products, such a reaction is referred to as:

A) an entropic reaction.
B) an endergonic reaction.
C) an exergonic reaction.
D) an enthalpic reaction.
E) an activation reaction.

Question 5

Which of the following statements is contrary to the first law of thermodynamics?

A) When gasoline is burned, its energy is destroyed.
B) Energy can be transferred from one form to another.
C) Energy can be converted from one form to another.
D) Matter can be converted into energy.
E) The amount of energy in the universe is constant.

Question 6

A reaction with a negative value of $\Delta$ G is referred to as an __________ reaction.

A) endergonic
B) entropy
C) exergonic
D) enthalpy
E) activation

Question 7

In order for a cell to maintain a high degree of order, it must:

A) constantly release energy.
B) constantly produce energy.
C) constantly destroy energy.
D) constantly use energy.
E) constantly increase energy.

Question 8

An endergonic reaction can proceed only if it absorbs:

A) more free energy than is released by a coupled exergonic reaction.
B) less free energy than was released by a coupled endergonic reaction.
C) less free energy than is released by a coupled exergonic reaction.
D) the same amount of free energy that is absorbed by the enzymatic breakdown of proteins.
E) energy from ADP, forming ATP.

Question 9

Kilojoules are:

A) units of heat energy.
B) units of matter.
C) units of work.
D) units of kinetics.
E) units of mechanical change.

Question 10

Which of the following statements is true of spontaneous reactions?

A) The amount of free energy after the reaction is less than before the reaction.
B) The amount of disorder after the reaction is less than before the reaction.
C) The amount of free energy after the reaction is more than before the reaction.
D) The amount of disorder is the same before and after the reaction.
E) The amount of enthalpy is more after the reaction than before the reaction.

Question 11

The sum of all chemical activities taking place in an organism is:

A) anabolism.
B) catabolism.
C) metabolism.
D) dehydration synthesis.
E) condensation reactions.

Question 12

An exergonic reaction is considered to be:

A) spontaneous.
B) potentially spontaneous.
C) endergonic.
D) nonspontaneous.
E) energy requiring.

Question 13

The ultimate source of energy for almost all living organisms is:

A) heat.
B) glucose.
C) carbohydrates.
D) lipids.
E) the sun.

Question 14

Every type of chemical bond contains a certain amount of energy.The total bond energy, which is essentially equivalent to the total potential energy of the system, is a quantity known as:

A) entropy.
B) kinetic energy.
C) thermodynamic energy.
D) enthalpy.
E) free energy.

Question 15

Only 20% to 30% of the energy stored in the chemical bonds of gasoline molecules is transformed into mechanical energy; the other 70% to 80% is dissipated as waste heat.Which statement explains this phenomenon?

A) The first law of thermodynamics.
B) The second law of thermodynamics.
C) When energy is converted from one form to another, some of the energy is converted into heat.
D) Both the first and second laws of thermodynamics.
E) Both the second law of thermodynamics, as well as the observation that the conversion of energy involves some energy being converted to heat.

Question 16

Which word is defined by this statement: A measure of this disorder, or randomness?

A) energy
B) entropy
C) enthalpy
D) mass
E) catabolism

Question 17

Pathways that have an overall energy requirement are referred to as:

A) catabolic reactions.
B) anabolic reactions.
C) energy-releasing reactions.
D) energetically feasible reactions.
E) reactions that will proceed spontaneously.

Question 18

Catabolic reactions involve the:

A) breakdown of large organic molecules to simple building blocks.
B) breakdown of life sustaining processes within cells.
C) building up of complex organic molecules from simple building blocks.
D) anabolic production of complex molecules.
E) expenditure of energy.

Question 19

The equation, G = H -TS, predicts that:

A) as entropy increases, the amount of free energy decreases.
B) as enthalpy increases, the amount of free energy increases.
C) as enthalpy decreases, the amount of entropy also decreases.
D) metabolism decreases proportionately to anabolism.
E) metabolism increases proportionately to catabolism.

Question 20

Most components of energy conversion systems evolved very early; thus, the most fundamental aspects of energy metabolism tend to be:

A) quite different among a diverse group of organisms.
B) very different among plants and animals.
C) the same among the autotrophs but different among heterotrophs.
D) the same among prokaryotes but different among eukaryotes.
E) very similar in a wide range of different organisms.

Question 21

Figure 7-1
Use the figure to answer the corresponding question(s).
Energy stored within the molecules of ATP is in the form of __________ energy.

A) kinetic
B) heat
C) potential
D) nuclear
E) light

Question 22

Which of the following statements concerning activation energy is FALSE?

A) Exergonic reactions have an energy of activation.
B) Endergonic reactions have an energy of activation.
C) Enzymes lower a reaction's activation energy.
D) Catalysts raise a reaction's activation energy.
E) Activation energy is the energy required to break existing bonds.

Question 23

Figure 7-1
Use the figure to answer the corresponding question(s).

-Which of the following conclusions can be accurately derived from the Figure 7-1?

A) $\Delta$ S is positive.
B) $\Delta$ H equals zero.
C) $\Delta$ G is positive.
D) $\Delta$ G is negative.
E) $\Delta$ T is negative.

Question 24

Enzymes are important biological catalysts because they:

A) supply the energy to initiate a biochemical reaction.
B) increase the free energy of a biochemical reaction.
C) lower the entropy of a biochemical reaction.
D) decrease the enthalpy of a biochemical reaction.
E) lower the activation energy of a biochemical reaction.

Question 25

The maintenance of a high ATP to ADP ratio within cells ensures that:

A) the hydrolysis of ADP to ATP will be strongly exergonic.
B) the hydrolysis of ATP to ADP will be strongly exergonic.
C) the hydrolysis of ATP to ADP will be strongly endergonic.
D) the hydrolysis of ADP to ATP will be an energy releasing reaction.
E) the conversion of ADP to ATP will proceed spontaneously.

Question 26

In a reaction in which the rate of the reverse reaction is equal to the rate of the forward reaction, a state of __________ is attained.

A) total entropy
B) enthalpy
C) thermodynamics
D) dynamic equilibrium
E) product reversibility

Question 27

Which of the following statements concerning enzymes is FALSE?

A) Each enzyme has an optimal temperature.
B) Each enzyme has an optimal pH.
C) Most enzymes are highly specific.
D) Some enzymes require cofactors.
E) Most enzymes are RNA molecules.

Question 28

Which of the following statements concerning ATP is FALSE?

A) It is a nucleotide.
B) It is called the energy currency of the cell.
C) It contains phosphate groups joined in a series.
D) It stores energy for long periods.
E) It contains phosphate groups joined by unstable bonds.

Question 29

Select the compound that contains the most energy:

A) AMP
B) ADP
C) ATP
D) P_i
E) AMP, ADP, ATP and P_i all contain equal amounts of energy.

Question 30

Select the phosphorylation reaction:

A) glucose + fructose $\rightarrow$ sucrose + H₂O
B) glucose + ATP $\rightarrow$ glucose-P + ADP
C) glucose-P + fructose $\rightarrow$ sucrose + P_i
D) glucose + glucose $\rightarrow$ maltose
E) sucrose + H₂O $\rightarrow$ glucose + fructose

Question 31

Select the reduced molecule:

A) NAD⁺
B) FAD
C) NADH
D) H ^-
E) NADP⁺

Question 32

The transfer of electrons from one compound to another is equivalent to __________ transfer.

A) heat
B) oxygen
C) enzymatic
D) phosphorus
E) energy

Question 33

FAD and cytochromes are classified as:

A) hydrogen or electron acceptors.
B) phosphate oxidizers.
C) phosphate reducers.
D) proteins that donate hydrogens or electrons.
E) redox intermediate catalysts.

Question 34

Select the hydrogen acceptor molecule that stores electrons in the process of photosynthesis:

A) nicotinamide adenine dinucleotide (NAD⁺)
B) nicotinamide adenine dinucleotide phosphate (NADP⁺)
C) flavin adenine dinucleotide (FAD)
D) adenine triphosphate (ATP)
E) adenine diphosphate (ADP)

Question 35

The reaction ATP + H₂O $\rightarrow$ ADP + P_i is classified as an:

A) endergonic reaction.
B) enthalpy reaction.
C) entropy reaction.
D) exergonic reaction.
E) intermediate phosphorylation reaction.

Question 36

Figure 7-2
Use the figure to answer the corresponding question(s).
Refer to Figure 7-2.The line on the graph labeled B represents the:

A) activation energy with an enzyme.
B) activation energy without an enzyme.
C) free energy of the reactants.
D) change in entropy.
E) change in enthalpy.

Question 37

__________ is a process where energy (as electrons) is released, whereas __________ is a process where energy (as electrons) is accepted.

A) Reduction; oxidation
B) Enthalpy; entropy
C) Entropy; enthalpy
D) Oxidation; reduction
E) Anabolism; catabolism

Question 38

Because enzymes affect the speed of chemical reactions without being consumed, they are referred to as:

A) hydrogen acceptors.
B) activation energy.
C) catalysts.
D) cytochromes.
E) transformation proteins.

Question 39

Figure 7-1
Use the figure to answer the corresponding question(s).
Which of the following statements about Figure 7-1 is true?

A) The reactants have more free energy than the products.
B) The products have more free energy than the reactants.
C) The figure represents a spontaneous reaction.
D) The figure represents an endergonic reaction.
E) The reaction is endergonic, and also the products have more free energy than the reactants.

Question 40

Consider the following two chemical equations: A.
Glucose + fructose $\rightarrow$ sucrose + H2O, $\Delta$ G = +27kJ/mole (or +6.5 kcal/mole)
B. Glucose + fructose + ATP $\rightarrow$ sucrose + ADP + P_i, $\Delta$ G = -5kJ/mole (or -1.2 kcal/mole)
The free energy change difference between the chemical equations (A) and (B) above is accomplished by:

A) a decrease in activation energy.
B) combining two endergonic reactions.
C) combining an endergonic and an exergonic reaction.
D) combining two exergonic reactions.
E) measuring the reaction rate.

Question 41

If one continues to increase the temperature in an enzyme-catalyzed reaction, the rate of the reaction:

A) does not change.
B) increases and then levels off.
C) decreases and then levels off.
D) increases and then decreases rapidly.
E) decreases and then increases rapidly.

Question 42

Figure 7-2
Use the figure to answer the corresponding question(s).
Parts of the enzyme molecule that interact with a substrate are called:

A) cofactors.
B) active sites.
C) induced-fit models.
D) orientation sites.
E) reaction sites.

Question 43

A closed system does not exchange energy with its surroundings.
__________________

Question 44

Hydrolases are one important class of enzyme that function to catalyze:

A) splitting a molecule using water.
B) conversions between isomers.
C) reactions in which double bonds are formed.
D) oxidation-reduction reactions.
E) the transfer of a functional group.

Question 45

What is "coupling of chemical reactions"? Provide two relevant biological examples to help explain the importance of this process to living organisms.

Question 46

An allosteric enzyme:

A) has an active site that binds to the substrate and an allosteric site that binds to the product.
B) allows the movement of molecules and ions from one part of the cell to another.
C) catalyzes both oxidation and reduction reactions.
D) raises a reaction's activation energy so that the rate of the reaction declines.
E) allows a substance other than the substrate to bind to the enzyme, thereby activating or inactivating it.

Question 47

Select the enzyme that does not match the reaction:

A) sucrase-splits sucrose into glucose and fructose
B) lipase-breaks ester linkages
C) phosphatase-removes phosphate groups
D) urease-converts urea to ammonia and CO₂
E) kinase-breaks peptide bonds

Question 48

What refers to the situation in which the binding of a substrate to the enzyme causes a change in the enzyme's shape, facilitating an enzyme's function?

A) active site
B) cofactor
C) activation energy
D) induced fit
E) allosteric inhibition

Question 49

Which refers to an organic, nonpolypeptide compound that binds to the apoenzyme and serves as a cofactor?

A) coenzyme
B) catalyst
C) substrate
D) mineral
E) allosteric regulator

Question 50

Figure 7-2
Use the figure to answer the corresponding question(s).
Refer to Figure 7-2.The line on the graph labeled C represents the:

A) activation energy with an enzyme.
B) activation energy without an enzyme.
C) change in free energy.
D) change in entropy.
E) change in enthalpy.

Question 51

Chemical energy is a form of kinetic energy.
__________________

Question 52

Explain the second law of thermodynamics in your own words, and briefly explain how this law applies to living organisms.

Question 53

You conduct an experiment in which you add increasing amounts of substrate to an enzyme solution and then measure the resulting reaction rate.You graph your results, plotting the rate of the reaction on the Y-axis versus substrate concentration on the X-axis.What do you conclude from your graph?

A) The reaction rate is directly proportional to substrate concentration.
B) The reaction rate is independent of substrate concentration.
C) The reaction rate increases but then decreases, forming a bell-shaped curve.
D) The reaction rate decreases with increasing substrate concentration.
E) The reaction rate increases with increasing substrate concentration up to a point, above which the rate remains constant.

Question 54

How does the ability of ATP to transfer a phosphate group make it pivotal in the overall energy metabolism of a cell?

Question 55

The substance on which an enzyme acts is called the:

A) substrate.
B) product.
C) ATP.
D) free energy.
E) cofactor.

Question 56

Explain the process of feedback inhibition.What role do allosteric regulators play in this process?

Question 57

Compare and contrast potential and kinetic energy.Give two examples that clarify the differences between the two.

Question 58

Competitive inhibitors inhibit biochemical reactions in such a way as to seemingly:

A) increase the concentration of substrate.
B) reduce the concentration of enzyme.
C) increase the concentration of enzyme.
D) reduce the concentration of substrate.
E) denature the enzyme.

Question 59

Which of the following does not represent a method by which cells regulate enzyme activity?

A) controlling the intracellular concentration of the enzyme
B) feedback inhibition of enzymes
C) the binding of allosteric regulators to allosteric sites on the enzyme
D) differential gene expression of the genes that produce enzymes
E) heat denaturation of the enzyme

Question 60

Penicillin is a drug that acts by:

A) irreversibly inhibiting transpeptidase.
B) reversibly inhibiting transpeptidase.
C) competitively inhibiting transpeptidase.
D) noncompetitively inhibiting transpeptidase.
E) denaturing transpeptidase.

Question 61

It is a fact that enzymes are highly specific and will only catalyze one or a few reactions.Can you think of a benefit that is derived from such specificity? (i.e.What would happen if most biochemical reactions were catalyzed by the same enzyme?)

Question 62

The cell maintains a ratio of ATP to ADP that is at the equilibrium point.
__________________

Question 63

ATP is a type of nucleotide.
__________________

Question 64

FAD becomes oxidized when it accepts hydrogen atoms and their electrons.
__________________

Question 65

How is it possible for an enzyme to lower the required energy of activation for a reaction?

Question 66

An enzyme raises the activation energy of the reaction it catalyzes.
__________________

Question 67

In the equation H = G + TS, the H stands for free energy.
__________________

Question 68

In competitive inhibition, the inhibitor binds to the enzyme at the allosteric site.
__________________

Question 69

Most vitamins are coenzymes.
__________________

Question 70

At a constant temperature and pH, the rate of an enzymatically catalyzed reaction is inversely proportional to the enzyme concentration.
__________________

Question 71

A cell must expend energy to produce a concentration gradient.
__________________

Question 72

An enzyme binds its substrate at the active site.
__________________

Question 73

Living cells maintain biochemical reactions far from equilibrium conditions.They do this by constantly manipulating the concentrations of reactants and products.Why is it important that a state far from equilibrium be maintained?

Question 74

The conversion of polysaccharides to monosaccharides is an example of an anabolic reaction.
__________________

Question 75

According to the second law of themodynamics, energy cannot be created nor destroyed.
__________________

Question 76

An exergonic reaction results in a net gain of free energy.
__________________