Deck 7: Energy and Metabolism

Question 1

Suppose the free energy of the reactants is greater than the free energy of the products. Such a reaction is referred to as a(n) ____.

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

Answer 1

C

Question 2

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(n):

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

Answer 2

B

Question 3

Figure 7-1 Which statement best describes the plot in the accompanying figure?

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

Answer 3

E

Question 4

Energy that is useable and organized is classified as having ____.

A) low energy
B) low entropy
C) low enthalpy
D) high entropy
E) high energy

Question 5

You are out cycling and start to climb a hill. As you crest the hill, just before cycling down, what energy have you stored?

A) kinetic energy
B) thermal energy
C) chemical energy
D) electrical energy
E) potential energy

Question 6

What process occurs when complex molecules are synthesized from simpler substances?

A) anabolism
B) catabolism
C) metabolism
D) condensation
E) phosphorylation

Question 7

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 8

What is the ultimate source of energy for almost all living organisms?:

A) heat
B) lipids
C) the sun
D) glucose
E) carbon dioxide

Question 9

As you climb a flight of stairs, what type of energy are your legs in motion using?

A) kinetic energy
B) thermal energy
C) chemical energy
D) electrical energy
E) potential energy

Question 10

Consider the following two chemical equations:
A) glucose + fructose → sucrose + H₂O, Δ G = +27kJ/mole (or +6.5 kcal/mole)
B) glucose + fructose + ATP → sucrose + ADP + P_i, Δ G = − 5kJ/mole (or − 1.2 kcal/mole)
What is the overall Δ G ?

A) 22 kJ/mole
B) 32 kJ/mole
C) -32 kJ/mole
D) -135 kJ/mole
E) 135 kJ/mole

Question 11

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) enthalpy.
C) free energy.
D) kinetic energy.
E) thermodynamic energy.

Question 12

Figure 7-1 Which conclusion can be accurately derived from the accompanying figure?

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

Question 13

Which best describes a catabolic reaction?

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

Question 14

According to the second law of thermodynamics, the amount of usable energy available to do work in the universe ____ over time.

A) crashes
B) decreases
C) increases
D) stays constant
E) exponentially increases

Question 15

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

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

Question 16

What unit is used to measure the thermal energy that flows from an object of a higher temperature to an object of a lower temperature?

A) kilograms
B) kilometers
C) kilowatts
D) kilocalories
E) kilojoules

Question 17

Why type of energy is represented by a positive change in G ?

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

Question 18

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

Question 19

An endergonic reaction can proceed only if it absorbs:

A) randomly available free energy.
B) less free energy than is released by a coupled exergonic reaction.
C) more free energy than is released by a coupled exergonic reaction.
D) less free energy than is released by a coupled endergonic reaction.
E) the same amount of free energy that is absorbed by the enzymatic breakdown of proteins.

Question 20

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

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

Question 21

Why are enzymes considered important biological catalysts?

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

Question 22

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

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

Question 23

What form of energy is stored within the molecules of ATP?

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

Question 24

Which best describes the energy of activation?

A) A type of exergonic reaction
B) A type of endergonic reaction
C) The energy required to break existing bonds
D) The catalysts needed to raise a reaction's rate
E) The enzymes required to lower a reaction's rate

Question 25

Which of the following is a hydrogen ion acceptor?

A) ATP
B) ADP
C) FAD
D) FADH
E) NADPH

Question 26

Figure 7-2 Refer to the accompanying figure. The line on the graph labeled B represents the ____.

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

Question 27

Which of the following statements concerning ATP is FALSE?

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

Question 28

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

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

Question 29

The direction of an exergonic reaction can best be describe as moving:

A) from higher to lower entropy.
B) from lower to higher free energy.
C) from higher to lower free energy.
D) from higher to lower absolute temperature.
E) from lower to higher absolute temperature.

Question 30

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

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

Question 31

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

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

Question 32

Which chemical process occurs in which a substance loses electrons?

A) entropy
B) enthalpy
C) oxidation
D) reduction
E) anabolism

Question 33

Figure 7-2 Refer to the accompanying figure. The line on the graph labeled C represents the ____.

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

Question 34

Select the phosphorylation reaction.

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

Question 35

The reaction ATP + H₂O → ADP + P_i is classified as an:

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

Question 36

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) induced fit
D) activation energy
E) allosteric inhibition

Question 37

Consider the following two chemical equations:
A) glucose + fructose → sucrose + H₂O, Δ G = +27kJ/mole (or +6.5 kcal/mole)
B) glucose + fructose + ATP → sucrose + ADP + P_i, Δ 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 38

Identify which compound has been reduced: XH₂ + NAD⁺ → X + NADH + H⁺.

A) XH₂
B) NAD⁺
C) X
D) NADH
E) H⁺

Question 39

What is needed in the following reaction: ____ + Pi + energy → ADP.

A) ATP
B) H₂O
C) AMP
D) cAMP
E) glucose-P

Question 40

What are the parts of the enzyme molecule that interact with a substrate called?

A) cofactors
B) active sites
C) reaction sites
D) enzyme product sites
E) enzyme-substrate complexes

Question 41

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

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

Question 42

In what method do competitive inhibitors inhibit biochemical reactions?

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

Question 43

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

Question 44

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

Question 45

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

Question 46

What do hydrolases catalyze?

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

Question 47

Chemical energy is a form of kinetic energy.
__________________

Question 48

Scientists usually name enzymes by adding what suffix to the name of the substrate with which the enzyme is associated?

A) -ase
B) -tic
C) -yst
D) -lose
E) -ator

Question 49

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

Question 50

Many bacterial infections are treated with drugs, such as penicillin and sulpha drugs, that ____ the bacterium's enzyme activity.

A) inhibit
B) promote
C) decrease
D) stabilize
E) accentuate

Question 51

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

Question 52

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

Question 53

Some enzymes have a receptor site that is other than the active site. This is also referred to as a(n) ____ site.

A) sensitive
B) allosteric
C) inhibitive
D) reversible
E) competitive

Question 54

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 55

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

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

Question 56

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

Question 57

You conduct an experiment in which you add increasing amounts of substrate to an enzyme solution and then measure the resulting reaction rate. You plot 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 independent of substrate concentration.
B) The reaction rate decreases with increasing substrate concentration.
C) The reaction rate is directly proportional to substrate concentration.
D) The reaction rate increases but then decreases, forming a bell-shaped curve.
E) The reaction rate increases with increasing substrate concentration up to a point, above which the rate remains constant.

Question 58

What would happen if you were to increase the temperature in an enzyme-catalyzed reaction?

A) The rate of reaction will not change.
B) The rate of reaction will increase and then level off.
C) The rate of reaction will decrease and then level off.
D) The rate of reaction will increase and then decrease rapidly.
E) The rate of reaction will decrease and then increase rapidly.

Question 59

The conversion of polysaccharides to monosaccharides is an example of a(n) anabolic reaction.
__________________

Question 60

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

Question 61

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

Question 62

An enzyme binds its substrate at the active site .
__________________

Question 63

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 64

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

Question 65

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

Question 66

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

Question 67

A(n) exergonic reaction results in a net gain of free energy.
__________________

Question 68

Most vitamins are coenzymes .
__________________

Question 69

ATP is a type of nucleotide .
__________________

Question 70

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

Question 71

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 72

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

Question 73

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