Question 1

When there is an excess of nutrients available in the human body, insulin is released to stimulate the synthesis of glycogen from glucose.This is a specific example of a/an __________ process, a general process in which larger molecules are made from smaller molecules.

Accepted Answer

A)  metabolic
B)  catabolic
C)  anabolic
D)  biosynthetic C

Question 2

A chemical reaction is defined as spontaneous if there is a net loss of free energy during the reaction process.However, spontaneous reactions do not always occur rapidly.Favorable biological reactions require __________ to selectively speed up reactions and meet the demands of the cell.

Accepted Answer

A)  heat
B)  ATP
C)  ions
D)  enzymes D

Question 3

Consider a description of an enzymatic reaction pathway that begins with the binding of substrate S to enzyme E, and ends with the release of product P from the enzyme. E + S → ES → EP → E + P In many circumstances, K_m = [E][S]/[ES] A.What proportion of enzyme molecules is bound to substrate when [S] = K_m? B.Recall that when [S] = K_m, the reaction rate is ½V_max.Does your answer to part A make sense in the light of this rate information?

Accepted Answer

A.When [S] is substituted for K_m in the equation, it becomes clear that [E] = [ES].Thus, half of the enzyme molecules are free and half are bound to the substrate. B.Yes.If half of the enzyme molecules are bound to the substrate, it makes intuitive sense that the reaction rate is half of the maximum possible rate, or half of the rate observed when all of the enzyme molecules are bound to the substrate.

Question 4

A.You are measuring the effect of temperature on the rate of an enzyme-catalyzed reaction.If you plot reaction rate against temperature, which of the graphs in Figure 3-64 would you expect your plot to resemble?
B.Explain why temperature has this effect.  
Figure 3-64

Accepted Answer

The answer of A.You are measuring the effect of temperature...

Question 5

Hydrolysis reactions are commonly used inside the cell to split high-energy covalent bonds.For each of the three reactions below, use the ΔG° for each reaction to determine the equilibrium constants (K).Assume that each reaction occurs independently of the other two.
ΔG° (kcal/mole)
Reaction 1: acetyl-P → acetate + P −10.3
Reaction 2: ATP → ADP + P −7.3
Reaction 3: glucose 6-P → glucose + P −3.3

Accepted Answer

The answer of Hydrolysis reactions are commonly used inside the...

Question 6

If you weigh yourself on a scale one morning, then eat four pounds of food during the day, will you weigh four pounds more the next morning? Why or why not? (Hint: What happens to the atoms from the food you ingested?)

Accepted Answer

The answer of If you weigh yourself on a scale...

Question 7

ΔG° indicates the change in the standard free energy as a reactant is converted to product.Given what you know about these values, which reaction below is the most favorable?

Accepted Answer

A)  ADP + Pi → ATP                                                      ΔG° = +7.3 kcal/mole
B)  glucose 1-phosphate → glucose 6-phosphate           ΔG° = −1.7 kcal/mole
C)  glucose + fructose → sucrose                                   ΔG° = +5.5 kcal/mole
D)  glucose → CO2 + H2O                                              ΔG° = −686 kcal/mole

Question 8

Oxidation is a favorable process in an aerobic environment, which is the reason cells are able to derive energy from the oxidation of macromolecules.Once carbon has been oxidized to __________, its most stable form, it can only cycle back into the organic portion of the carbon cycle through __________.

Accepted Answer

A)  CO2; photosynthesis.
B)  CH3; combustion.
C)  CO2; respiration.
D)  CO; reduction.

Question 9

The addition of a new deoxynucleotide to a growing DNA chain requires more energy than can be obtained by the hydrolysis of ATP to ADP + P_i.What alternative series of reactions is used, and how does this help overcome the energy barrier for DNA synthesis?

Accepted Answer

The answer of The addition of a new deoxynucleotide to...

Question 10

ΔG measures the change of free energy in a system as it converts reactant (Y) into product (X).When [Y] = [X], ΔG is equal to

Accepted Answer

A)  ΔG° + RT.
B)  RT.
C)  ln [X]/[Y].
D)  ΔG°.

Question 11

Even though cellular macromolecules contain a large number of carbon and hydrogen atoms, they are not all spontaneously converted into CO2 and H2O.This absence of spontaneous combustion is due to the fact that biological molecules are relatively __________ and an input of energy is required to reach lower energy states.

Accepted Answer

A)  large
B)  polar
C)  stable
D)  unstable

Question 12

Isomerization of glucose 1-phosphate to glucose 6-phosphate is energetically favorable.At 37°C, ΔG° = −1.42 log10K.What is the equilibrium constant for this reaction if ΔG° = −1.74 kcal/mole at 37°C?

Accepted Answer

A)  16.98
B)  0.09
C)  −0.09
D)  0.39

Question 13

Which of the following statements is FALSE for a favorable binding reaction?

Accepted Answer

A)  The free-energy change is negative for the system.
B)  The concentration of the complex remains lower than the concentration of the unbound components.
C)  The complex dissociation rate is slower than the rate for component association.
D)  The binding energy for the association is large and negative.

Question 14

Oxidation is the process by which oxygen atoms are added to a target molecule.Generally, the atom that is oxidized will experience which of the following with respect to the electrons in its outer shell?

Accepted Answer

A)  a net gain
B)  a net loss
C)  no change
D)  an equal sharing

Question 15

The equilibrium constant for complex formation between molecules A and B will depend on their relative concentrations, as well as the rates at which the molecules associate and dissociate.The association rate will be larger than the dissociation rate when complex formation is favorable.The energy that drives this process is referred to as __________ energy.

Accepted Answer

A)  dissociation
B)  association
C)  binding
D)  releasing

Question 16

For each of the pairs A-D in Figure 3-54, pick the more reduced member of the pair. $\quad$$\quad$$\quad$$\quad$(i)$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$(ii)

(A)$\quad$$\quad$$\quad$$ \mathrm{Fe}^{3+} $$\quad$$\quad$$\quad$$\quad$ $ \mathrm{Fe}^{2+} $

(B)$\quad$$\quad$$\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}$$\quad$$\quad$$\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{3}$

(C)
$\quad$$\quad$  $\quad$

(D)$\quad$$\quad$$\mathrm{H}-\mathrm{O}-\mathrm{O}-\mathrm{H}$ $\quad$$\quad$$\mathrm{H}-\mathrm{O}-\mathrm{H}$
 
Figure 3-54

Accepted Answer

The answer of For each of the pairs A-D in...

Question 17

In general, there is a positive change in free energy associated with reduction reactions, and most of them are coupled with oxidation reactions.The last step in the biosynthesis of cholesterol involves the reduction of a carbon-carbon double bond.What activated carrier molecule is used in this reaction (and generally for the reduction of lipids) and how would this reaction be influenced by the levels of available ATP?

Accepted Answer

The answer of In general, there is a positive change...

Question 18

The graph in Figure 3-34 illustrates the change in the rate of an enzyme-catalyzed reaction as the concentration of substrate is increased.Which of the values listed below is used to calculate the enzyme turnover number?  Figure 3-34

Accepted Answer

A)  ½Vmax
B)  Km
C)  Vmax
D)  Vmax − Km

Question 19

The anhydride formed between a carboxylic acid and a phosphate (Figure 3-45A) is a high-energy intermediate for some reactions in which ATP is the energy source.Arsenate can also be incorporated into a similar high-energy intermediate in place of the phosphate (Figure 3-45B).Figure 3-45C shows the reaction profiles for the hydrolysis of these two high-energy intermediates.What is the effect of substituting arsenate for phosphate in this reaction? (A)

(B)

Figure 3-45

Accepted Answer

A)  It forms a high-energy intermediate of lower energy.
B)  It forms a high-energy intermediate of the same energy.
C)  It decreases the stability of the high-energy intermediate.
D)  It increases the stability of the high-energy intermediate.

Question 20

Your body extracts energy from the food you ingest by catalyzing reactions that essentially "burn" the food molecules in a stepwise fashion.What is another way to describe this process?

Accepted Answer

A)  reduction
B)  oxidation
C)  dehydration
D)  solvation

Exam 3: Energy, Catalysis, and Biosynthesis

When there is an excess of nutrients available in the human body, insulin is released to stimulate the synthesis of glycogen from glucose.This is a specific example of a/an __________ process, a general process in which larger molecules are made from smaller molecules.

A chemical reaction is defined as spontaneous if there is a net loss of free energy during the reaction process.However, spontaneous reactions do not always occur rapidly.Favorable biological reactions require __________ to selectively speed up reactions and meet the demands of the cell.

A.You are measuring the effect of temperature on the rate of an enzyme-catalyzed reaction.If you plot reaction rate against temperature, which of the graphs in Figure 3-64 would you expect your plot to resemble? B.Explain why temperature has this effect. Figure 3-64

If you weigh yourself on a scale one morning, then eat four pounds of food during the day, will you weigh four pounds more the next morning? Why or why not? (Hint: What happens to the atoms from the food you ingested?)

ΔG° indicates the change in the standard free energy as a reactant is converted to product.Given what you know about these values, which reaction below is the most favorable?

Oxidation is a favorable process in an aerobic environment, which is the reason cells are able to derive energy from the oxidation of macromolecules.Once carbon has been oxidized to , its most stable form, it can only cycle back into the organic portion of the carbon cycle through .

The addition of a new deoxynucleotide to a growing DNA chain requires more energy than can be obtained by the hydrolysis of ATP to ADP + P_i.What alternative series of reactions is used, and how does this help overcome the energy barrier for DNA synthesis?

ΔG measures the change of free energy in a system as it converts reactant (Y) into product (X) .When [Y] = [X], ΔG is equal to

Isomerization of glucose 1-phosphate to glucose 6-phosphate is energetically favorable.At 37°C, ΔG° = −1.42 log₁₀K.What is the equilibrium constant for this reaction if ΔG° = −1.74 kcal/mole at 37°C?

Which of the following statements is FALSE for a favorable binding reaction?

Oxidation is the process by which oxygen atoms are added to a target molecule.Generally, the atom that is oxidized will experience which of the following with respect to the electrons in its outer shell?

The graph in Figure 3-34 illustrates the change in the rate of an enzyme-catalyzed reaction as the concentration of substrate is increased.Which of the values listed below is used to calculate the enzyme turnover number? Figure 3-34

Your body extracts energy from the food you ingest by catalyzing reactions that essentially "burn" the food molecules in a stepwise fashion.What is another way to describe this process?

Exam 3: Energy, Catalysis, and Biosynthesis

When there is an excess of nutrients available in the human body, insulin is released to stimulate the synthesis of glycogen from glucose.This is a specific example of a/an __________ process, a general process in which larger molecules are made from smaller molecules.

A chemical reaction is defined as spontaneous if there is a net loss of free energy during the reaction process.However, spontaneous reactions do not always occur rapidly.Favorable biological reactions require __________ to selectively speed up reactions and meet the demands of the cell.

A.You are measuring the effect of temperature on the rate of an enzyme-catalyzed reaction.If you plot reaction rate against temperature, which of the graphs in Figure 3-64 would you expect your plot to resemble? B.Explain why temperature has this effect. Figure 3-64

If you weigh yourself on a scale one morning, then eat four pounds of food during the day, will you weigh four pounds more the next morning? Why or why not? (Hint: What happens to the atoms from the food you ingested?)

ΔG° indicates the change in the standard free energy as a reactant is converted to product.Given what you know about these values, which reaction below is the most favorable?

The addition of a new deoxynucleotide to a growing DNA chain requires more energy than can be obtained by the hydrolysis of ATP to ADP + Pi.What alternative series of reactions is used, and how does this help overcome the energy barrier for DNA synthesis?

ΔG measures the change of free energy in a system as it converts reactant (Y) into product (X) .When [Y] = [X], ΔG is equal to

Isomerization of glucose 1-phosphate to glucose 6-phosphate is energetically favorable.At 37°C, ΔG° = −1.42 log10K.What is the equilibrium constant for this reaction if ΔG° = −1.74 kcal/mole at 37°C?

Which of the following statements is FALSE for a favorable binding reaction?

Oxidation is the process by which oxygen atoms are added to a target molecule.Generally, the atom that is oxidized will experience which of the following with respect to the electrons in its outer shell?

The graph in Figure 3-34 illustrates the change in the rate of an enzyme-catalyzed reaction as the concentration of substrate is increased.Which of the values listed below is used to calculate the enzyme turnover number? Figure 3-34

Your body extracts energy from the food you ingest by catalyzing reactions that essentially "burn" the food molecules in a stepwise fashion.What is another way to describe this process?

The addition of a new deoxynucleotide to a growing DNA chain requires more energy than can be obtained by the hydrolysis of ATP to ADP + P_i.What alternative series of reactions is used, and how does this help overcome the energy barrier for DNA synthesis?

Isomerization of glucose 1-phosphate to glucose 6-phosphate is energetically favorable.At 37°C, ΔG° = −1.42 log₁₀K.What is the equilibrium constant for this reaction if ΔG° = −1.74 kcal/mole at 37°C?