Question 1

Glyceraldehyde 3-phosphate dehydrogenase catalyzes the reaction between glyceraldehyde 3-phosphate, NAD⁺, and phosphate ion to form 1,3-bisphosphoglycerate and NADH.Under certain conditions, a permanently radiolabeled enzyme intermediate forms if ¹⁴C-glyceraldehyde 3-phosphate and NAD⁺ are used as substrates and phosphate is left out of the reaction mix.The radiolabeled molecule is linked to a cysteine side chain of the enzyme.This result suggests that this enzyme uses _______ as a catalytic mechanism.

Accepted Answer

The answer of Glyceraldehyde 3-phosphate dehydrogenase catalyzes the reaction between...

Question 2

Zinc or iron ions that bind to enzymes and aid in their function are called _______.

Accepted Answer

The answer of Zinc or iron ions that bind to...

Question 3

It is estimated that approximately 90 percent of energy that passes between levels in a food web is lost at each level.Explain the first law of thermodynamics, and discuss why this apparent loss of energy does not contradict that law.

Accepted Answer

The answer of It is estimated that approximately 90 percent...

Question 4

Refer to the figure below.  The figure illustrates how _______ of a key enzyme in a metabolic pathway can shift the flow of molecules into a different pathway.

Accepted Answer

The answer of Refer to the figure below.  The...

Question 5

The greater the affinity of an enzyme for its substrate, the _______ the substrate dissociation constant (K_D).

Accepted Answer

The answer of The greater the affinity of an enzyme...

Question 6

Refer to the table below.  The table shows data collected from three forms of the same enzyme-one normal form and two mutant forms.The data show that the _______ form has the greatest affinity for substrate.

Accepted Answer

The answer of Refer to the table below.  The...

Question 7

When an enzyme is heated until its three-dimensional structure is destroyed, the enzyme is said to be _______.

Accepted Answer

The answer of When an enzyme is heated until its...

Question 8

Two amino acids shown to be essential in the catalytic mechanism of phosphohexose isomerase are a histidine and a lysine.These two side chains work together in a reversible series of protonation and deprotonation steps to break one bond in the substrate and form a new one.This is an example of a(n) _______ mechanism of catalysis.

Accepted Answer

The answer of Two amino acids shown to be essential...

Question 9

A change in enzyme shape caused by substrate binding is called _______.

Accepted Answer

The answer of A change in enzyme shape caused by...

Question 10

Refer to the figure below.  The figure shows activities at the active site of the enzyme hexokinase as it catalyzes a reaction between ATP and glucose.Based on this figure, it can be inferred that the magnesium ion functions to _______ the ATP molecule so it can be attacked by glucose.

Accepted Answer

The answer of Refer to the figure below.  The...

Question 11

Refer to the figure and table below.   A student is constructing a table that lists poisons whose mechanisms of action involve enzyme inhibition. She will put a checkmark in any column that characterizes a compound's mode of inhibition.Arsenate acts to inhibit many enzymes that use ATP as a coenzyme.To complete this row in the table the student should check the box(es) under _______.

Accepted Answer

The answer of Refer to the figure and table below....

Question 12

Each day, an adult human uses approximately 2,000 kilocalories of metabolic energy.This quantity of energy can be supplied by about 250 moles of ATP as it hydrolyzes to ADP and P_i.At any one time, there is much less than this quantity of ATP present in the human body.Therefore, the production of ATP must be tightly regulated so that appropriate amounts are available, depending on need.For example, certain enzymes involved in ATP production will be _______ when a person shifts from high levels of activity to a period of sleep.

Accepted Answer

The answer of Each day, an adult human uses approximately...

Question 13

Refer to the figure below.  Hexokinase catalyzes the reaction between glucose and ATP to form glucose 6-phosphate and ADP.The figure shows how the active site of hexokinase orients ATP for attack by glucose during the reaction.In the absence of enzyme, this reaction would be much slower because there would be a _______ number of orientations of the two substrates compared with the number of orientations provided by the enzyme.

Accepted Answer

The answer of Refer to the figure below.  Hexokinase...

Question 14

Discuss the meaning of the term "thermodynamics," and explain how biological systems and thermodynamics are related.

Accepted Answer

The answer of Discuss the meaning of the term "thermodynamics,"...

Question 15

Refer to the figure below.  Portions of three biosynthetic pathways regulated through feedback inhibition and activation are shown.Two of these pathways intersect at carbamoyl phosphate.The third pathway generates a product that activates production of carbamoyl phosphate through allosteric modification of the enzyme carbamoyl phosphate synthetase.In this set of pathways, arginine biosynthesis is shut down through feedback inhibition when _______ and arginine reach high levels of concentration.

Accepted Answer

The answer of Refer to the figure below.  Portions...

Question 16

A chemical reaction is found to have an equilibrium constant of 0.95, which means that there are almost equal concentrations of products and reactants when equilibrium is achieved.If an enzyme is added that will catalyze this reaction, the reaction rate will _______ and the equilibrium point will not change.

Accepted Answer

The answer of A chemical reaction is found to have...

Question 17

Refer to the figure below.  Enzymes use a variety of strategies for inducing substrates to assume their transition states.Of the three strategies shown in the figure, labeled A, B, and C, the two that operate using physical mechanisms are _______.

Accepted Answer

The answer of Refer to the figure below.  Enzymes...

Question 18

Refer to the figure below.  This cellular reaction is catalyzed by the enzyme triosephosphate isomerase.At equilibrium, the ratio of dihydroxyacetone phosphate to glyceraldehyde phosphate is 24:1.What changes in conditions in the cell will cause changes in the direction of flux through this reaction? Give two changes, one that will cause a change in flux in the forward direction, and a second that will cause change in the reverse direction.

Accepted Answer

The answer of Refer to the figure below.  This...

Question 19

Plot free energy versus the time course of an endergonic reaction, and do the same for an exergonic reaction.Include the activation energy on both plots.Label E_a and $\Delta$G on both graphs.

Accepted Answer

The answer of Plot free energy versus the time course...

Question 20

Refer to the figures below.  These figures can be used to illustrate the first and second laws of thermodynamics.Assign each figure to one of these laws, then explain the difference between the figures.

Accepted Answer

The answer of Refer to the figures below.  These...

Quiz 8: Energy, Enzymes, and Metabolism

Zinc or iron ions that bind to enzymes and aid in their function are called _______.

It is estimated that approximately 90 percent of energy that passes between levels in a food web is lost at each level.Explain the first law of thermodynamics, and discuss why this apparent loss of energy does not contradict that law.

Refer to the figure below. The figure illustrates how _______ of a key enzyme in a metabolic pathway can shift the flow of molecules into a different pathway.

The greater the affinity of an enzyme for its substrate, the _______ the substrate dissociation constant (K_D).

Refer to the table below. The table shows data collected from three forms of the same enzyme-one normal form and two mutant forms.The data show that the _______ form has the greatest affinity for substrate.

When an enzyme is heated until its three-dimensional structure is destroyed, the enzyme is said to be _______.

A change in enzyme shape caused by substrate binding is called _______.

Refer to the figure below. The figure shows activities at the active site of the enzyme hexokinase as it catalyzes a reaction between ATP and glucose.Based on this figure, it can be inferred that the magnesium ion functions to _______ the ATP molecule so it can be attacked by glucose.

Discuss the meaning of the term "thermodynamics," and explain how biological systems and thermodynamics are related.

Refer to the figure below. Enzymes use a variety of strategies for inducing substrates to assume their transition states.Of the three strategies shown in the figure, labeled A, B, and C, the two that operate using physical mechanisms are _______.

Plot free energy versus the time course of an endergonic reaction, and do the same for an exergonic reaction.Include the activation energy on both plots.Label E_a and $\Delta$ G on both graphs.

Refer to the figures below. These figures can be used to illustrate the first and second laws of thermodynamics.Assign each figure to one of these laws, then explain the difference between the figures.

Quiz 8: Energy, Enzymes, and Metabolism

Zinc or iron ions that bind to enzymes and aid in their function are called _______.

It is estimated that approximately 90 percent of energy that passes between levels in a food web is lost at each level.Explain the first law of thermodynamics, and discuss why this apparent loss of energy does not contradict that law.

Refer to the figure below. The figure illustrates how _______ of a key enzyme in a metabolic pathway can shift the flow of molecules into a different pathway.

The greater the affinity of an enzyme for its substrate, the _______ the substrate dissociation constant (KD).

Refer to the table below. The table shows data collected from three forms of the same enzyme-one normal form and two mutant forms.The data show that the _______ form has the greatest affinity for substrate.

When an enzyme is heated until its three-dimensional structure is destroyed, the enzyme is said to be _______.

A change in enzyme shape caused by substrate binding is called _______.

Refer to the figure below. The figure shows activities at the active site of the enzyme hexokinase as it catalyzes a reaction between ATP and glucose.Based on this figure, it can be inferred that the magnesium ion functions to _______ the ATP molecule so it can be attacked by glucose.

Discuss the meaning of the term "thermodynamics," and explain how biological systems and thermodynamics are related.

Refer to the figure below. Enzymes use a variety of strategies for inducing substrates to assume their transition states.Of the three strategies shown in the figure, labeled A, B, and C, the two that operate using physical mechanisms are _______.

Plot free energy versus the time course of an endergonic reaction, and do the same for an exergonic reaction.Include the activation energy on both plots.Label Ea and Δ\DeltaΔ G on both graphs.

Refer to the figures below. These figures can be used to illustrate the first and second laws of thermodynamics.Assign each figure to one of these laws, then explain the difference between the figures.

The greater the affinity of an enzyme for its substrate, the _______ the substrate dissociation constant (K_D).

Plot free energy versus the time course of an endergonic reaction, and do the same for an exergonic reaction.Include the activation energy on both plots.Label E_a and $\Delta$ G on both graphs.