Deck 7: Energy and Metabolism

Question 1

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

Answer 1

A

Question 2

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

Answer 2

D

Question 3

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.

Answer 3

B

Question 4

The unit of measurement for energy that most biologists today prefer is ____________.

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

Question 5

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 6

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

A) Entropy
B) Enthalpy
C) Exergonic
D) Endergonic
E) Activation

Question 7

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.

Question 8

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 9

Capacity to do work as a result of position or state is known as _______.

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

Question 10

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 11

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

Question 12

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 13

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

A) Kilograms
B) Kilometers
C) Kilowatts
D) Kilocalories
E) Kilojoules

Question 14

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 15

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

A) Kinetic energy
B) Thermal energy
C) Chemical energy
D) Electrical energy
E) Potential energy

Question 16

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 synthesis of complex organic molecules from simple building blocks.

Question 17

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

A) Total entropy in the universe is decreasing with time.
B) When energy is used, it is irreplaceable.
C) Energy is converted from one form to another form.
D) Energy can be transferred from one form to another.
E) Total amount of energy in the universe that is available to do work decreases over time.

Question 18

Total bond energy is essentially equivalent to the total potential energy of the system, a quantity known as ____________.

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

Question 19

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

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

Question 20

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 21

Consider the following two chemical equations: A. glucose + fructose → sucrose + H₂O, Δ G = +27 kJ/mole (or +6.5 kcal/mole)
B) glucose + fructose + ATP → sucrose + ADP + P_i, Δ G = −5 kJ/mole (or −1.2 kcal/mole)
The overall free energy change in 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 22

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

A) Kinetic
B) Heat
C) Potential
D) Nuclear
E) Light

Question 23

The region of the enzyme molecule that interacts with a substrate is called the ______.

A) cofactor
B) active site
C) reaction site
D) enzyme product site
E) enzyme-substrate complex

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

What refers to the alteration of an enzyme's shape due to binding of substrate?

A) Active site
B) Cofactor
C) Induced fit
D) Activation energy
E) Allosteric inhibition

Question 26

Which class of enzyme can catalyze the conversion of a molecule from one isomeric form to another?

A) Hydrolases
B) Lyases
C) Ligases
D) Isomerases
E) Transferases

Question 27

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 28

Which of the following is a hydrogen ion acceptor?

A) ATP
B) ADP
C) FAD
D) FADH2
E) NADPH

Question 29

The direction of an exergonic reaction can best be described 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

Which chemical process occurs in which a substance loses electrons?

A) Entropy
B) Enthalpy
C) Oxidation
D) Reduction
E) Anabolism

Question 31

Which of the following statement is correct in the context of this equation H = G + TS?

A) Both enthalpy and free energy remain the same.
B) As the temperature increases, there is a decrease in random molecular motion.
C) As entropy decreases, the amount of free energy decreases.
D) As entropy increases, the amount of free energy decreases.
E) As entropy increases, the amount of free energy increases.

Question 32

Which of the following is the common cofactor for enzymes?

A) Zinc
B) Copper
C) Lead
D) Iron
E) Magnesium

Question 33

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 34

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

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

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

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 37

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 38

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 39

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 40

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 41

A nonpolypeptide compound that binds to the apoenzyme and serves as a cofactor is called

A) starch.
B) pyruvic acid.
C) serine.
D) heme.
E) coenzyme.

Question 42

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

A) Mineral
B) Catalyst
C) Substrate
D) Coenzyme
E) Allosteric regulator

Question 43

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

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

Question 44

_____________ is a protein-digesting enzyme in the very acidic stomach juice.

A) Trypsin
B) Chymotrypsin
C) Elastase
D) Pepsin
E) Dipeptidase

Question 45

What is the function of the oxidoreductases?

A) Catalyze conversion of a molecule from one isomeric form to another
B) Catalyze hydrolysis reactions
C) Catalyze oxidation-reduction reactions
D) Catalyze certain reactions in which double bonds form or break
E) Catalyze the transfer of a functional group from a donor molecule to an acceptor molecule

Question 46

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

Question 47

How do competitive inhibitors hinder 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 48

Chemical energy is a form of kinetic energy.

Question 49

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 50

Briefly explain what is meant by the phrase "coupling of chemical reactions." Provide an example to explain the importance of this process in living organisms.

Question 51

Use your own words to explain the second law of thermodynamics and how this law applies to living organisms.

Question 52

According to the Second Law of Thermodynamics, energy cannot be created nor destroyed.

Question 53

Compare potential and kinetic energy. Give one example of kinetic energy and one example of potential energy to clarify their differences.

Question 54

Enzyme names are usually derived from the name of its substrate followed by which suffix?

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

Question 55

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

Question 56

A closed system does not exchange energy with its surroundings.

Question 57

In noncompetitive inhibition, the inhibitor binds to the active site of the enzyme.

Question 58

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 59

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 60

Explain the process of allosteric enzyme regulation. What role do allosteric regulators play in this process?

Question 61

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

Question 62

Some enzymes can only function if an additional chemical component, called a cofactor, is present.

Question 63

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

Question 64

Briefly explain how an enzyme lowers the required energy of activation for a reaction.

Question 65

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

Question 66

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

Question 67

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

Question 68

What would happen if all chemical processes reached equilibrium in the cell? Briefly explain why cells work to prevent a state of equilibrium.

Question 69

Most vitamins are coenzymes.

Question 70

A reversible inhibitor forms weak chemical bonds with the enzyme.

Question 71

Enzymes are highly specific and will only catalyze one or a few reactions. What would happen if most biochemical reactions were catalyzed by the same enzyme?

Question 72

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

Question 73

A cell must expend energy to produce a concentration gradient.