Question 1

Fibrinogen is converted to _____ by the action of _____.

Accepted Answer

fibrin; fi...

Question 2

Which of the following is true regarding heparin?

Accepted Answer

A)   it is an allosteric activator of antithrombin
B)   it is a sulfated polysaccharide
C)   it simultaneously binds to antithrombin and the target of antithrombin
D)   it is used clinically as an anticoagulant
E)   all of the aboveF) A) and E)
G) B) and E) E

Question 3

Of the following ions, which would be most likely to participate in metal ion catalysis?

Accepted Answer

A)   Na+
B)   Zn2+
C)   Ag+
D)   K+
E)   Ba2+F) C) and E)
G) B) and D)

Question 4

The enzyme hexokinase catalyzes a reaction where its substrates are completely sequestered from the aqueous environment allowing for interactions to occur between enzyme and substrates that would not normally occur in an aqueous environment. What term describes this type of catalysis?

Accepted Answer

A)   electrostatic catalysis
B)   desolvation catalysis
C)   non-aqueous catalysis
D)   hydrogen-bonded catalysis
E)   closed-system catalysisF) C) and D)
G) A) and B)

Question 5

The blood coagulation cascade is triggered when ___ is converted to ___.

Accepted Answer

The answer of The blood coagulation cascade is triggered when...

Question 6

Of all the species that enzymes bind, they are thought to bind most tightly to _____.

Accepted Answer

A)   substrates
B)   products
C)   transition states
D)   intermediates
E)   all are bound very tightlyF) D) and E)
G) B) and C)

Question 7

Zymogens are not enzymatically active because _____.

Accepted Answer

A)   they do not contain the cofactors required for catalysis
B)   they are the product of mutated genes
C)   their active sites are distorted and incapable of enzymatic activity
D)   the pH of their environment is not optimal for activity
E)   none of the aboveF) C) and E)
G) C) and D)

Question 8

Conversion of factor X to factor Xa represents a(n)  _____ form of activation; binding of antithrombin to thrombin represents a(n)  _____ form of inhibition.

Accepted Answer

A)   reversible; reversible
B)   irreversible; reversible
C)   reversible; irreversible
D)   irreversible; irreversible
E)   none of the above since antithrombin is not an inhibitor of thrombinF) B) and C)
G) C) and D)

Question 9

Thrombin is similar to ___ as it cleaves peptide bonds following ___ residues.

Accepted Answer

The answer of Thrombin is similar to ___ as it...

Question 10

How does a catalyst increase the rate of a reaction?

Accepted Answer

A)   It makes the reaction more exergonic.
B)   It increases the temperature of the reaction.
C)   It allows reacting molecules to more easily form the transition state.
D)   It causes a localized increase in the concentration of reactants.
E)   None of the aboveF) B) and E)
G) A) and C)

Question 11

In the enzyme catalyzed decarboxylation of acetoacetate, a Schiff base is formed between the ketone of acetoacetate and a _____ residue in the active site of the enzyme.

Accepted Answer

A)   Arg
B)   Asn
C)   Lys
D)   Glu
E)   SerF) C) and D)
G) B) and E)

Question 12

How does a catalyst increase the rate of a reaction?

Accepted Answer

A)   it makes the reaction more exergonic
B)   it increases the temperature of the reaction
C)   it allows reacting molecules to more easily form the transition state
D)   it causes a localized increase in the concentration of reactants
E)   none of the aboveF) A) and C)
G) B) and D)

Question 13

Which of the following is a feature of protease inhibitor specific for trypsin?

Accepted Answer

A)   contains a positive charge to mimic the charge of the substrate
B)   ability to interact with the Ser of the catalytic triad
C)   inability to form the tetrahedral intermediate
D)   high affinity for the enzyme active site
E)   all of the aboveF) A) and B)
G) None of the above E

Question 14

Different enzymes that catalyze the same reaction are known as _____.

Accepted Answer

A)   transferases
B)   isomerases
C)   allosteric enzymes
D)   holoenzymes
E)   isozymesF) None of the above
G) D) and E) E

Question 15

Which protein in the blood is responsible for converting fibrinogen to fibrin?

Accepted Answer

A)   thrombin
B)   factor X
C)   factor VII
D)   factor VIIa
E)   prothrombinF) A) and B)
G) A) and E)

Question 16

The ability for an enzyme to pick out one particular substrate from the myriad of molecules floating around its environment is an example of _____.

Accepted Answer

A)   natural selection
B)   specificity
C)   high affinity
D)   processivity
E)   none of the aboveF) B) and E)
G) A) and D)

Question 17

Thrombin circulates in the blood as a(n) ___ that is called ___.

Accepted Answer

zymogen, p...

Question 18

If an enzyme rate increases 10-fold for every 5.7 kJ/mol decrease in the energy of activation, what rate increase would be observed if three H-bonds were stabilizing the transition state with each H-bond having a strength of 21 kJ/mol?

Accepted Answer

A)   11-fold increase
B)   37-fold increase
C)   60-fold increase
D)   100-fold increase
E)   1011-fold increaseF) B) and C)
G) A) and E)

Question 19

An organic molecule that is tightly bound to an enzyme and participates in an enzyme catalyzed reaction is specifically referred to as a _____.

Accepted Answer

A)   cofactor
B)   metal ion
C)   coenzyme
D)   cosubstrate
E)   prosthetic groupF) A) and B)
G) A) and C)

Question 20

In an enzyme mechanism that generates a negative charge in the transition state, which of the following would be most effective to have in the active site of the enzyme?

Accepted Answer

A)   transition metal cation
B)   Asp residue
C)   Gln residue
D)   transition metal anion
E)   none of the aboveF) B) and E)
G) C) and E)

Exam 6: How Enzymes Work

Fibrinogen is converted to _____ by the action of _____.

Correct Answerverifiedfibrin; fi...View AnswerShow Answer

Which of the following is true regarding heparin?

Correct AnswerverifiedE

Of the following ions, which would be most likely to participate in metal ion catalysis?

Correct AnswerverifiedShow Answer

The enzyme hexokinase catalyzes a reaction where its substrates are completely sequestered from the aqueous environment allowing for interactions to occur between enzyme and substrates that would not normally occur in an aqueous environment. What term describes this type of catalysis?

Correct AnswerverifiedShow Answer

The blood coagulation cascade is triggered when ___ is converted to ___.

Correct AnswerverifiedShow Answer

Of all the species that enzymes bind, they are thought to bind most tightly to _____.

Correct AnswerverifiedShow Answer

Zymogens are not enzymatically active because _____.

Correct AnswerverifiedShow Answer

Conversion of factor X to factor Xa represents a(n) _____ form of activation; binding of antithrombin to thrombin represents a(n) _____ form of inhibition.

Correct AnswerverifiedShow Answer

Thrombin is similar to ___ as it cleaves peptide bonds following ___ residues.

Correct AnswerverifiedShow Answer

How does a catalyst increase the rate of a reaction?

Correct AnswerverifiedShow Answer

In the enzyme catalyzed decarboxylation of acetoacetate, a Schiff base is formed between the ketone of acetoacetate and a _____ residue in the active site of the enzyme.

Correct AnswerverifiedShow Answer

How does a catalyst increase the rate of a reaction?

Correct AnswerverifiedShow Answer

Which of the following is a feature of protease inhibitor specific for trypsin?

Correct AnswerverifiedE

Different enzymes that catalyze the same reaction are known as _____.

Correct AnswerverifiedE

Which protein in the blood is responsible for converting fibrinogen to fibrin?

Correct AnswerverifiedShow Answer

The ability for an enzyme to pick out one particular substrate from the myriad of molecules floating around its environment is an example of _____.

Correct AnswerverifiedShow Answer

Thrombin circulates in the blood as a(n) ___ that is called ___.

Correct Answerverifiedzymogen, p...View AnswerShow Answer

If an enzyme rate increases 10-fold for every 5.7 kJ/mol decrease in the energy of activation, what rate increase would be observed if three H-bonds were stabilizing the transition state with each H-bond having a strength of 21 kJ/mol?

Correct AnswerverifiedShow Answer

An organic molecule that is tightly bound to an enzyme and participates in an enzyme catalyzed reaction is specifically referred to as a _____.

Correct AnswerverifiedShow Answer

In an enzyme mechanism that generates a negative charge in the transition state, which of the following would be most effective to have in the active site of the enzyme?

Correct AnswerverifiedShow Answer

Fibrinogen is converted to _ by the action of _.

Correct Answer
verified
fibrin; fi...
View Answer

Correct Answer
verified
E

Correct Answer
verified

Correct Answer
verified

The blood coagulation cascade is triggered when _ is converted to _.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Conversion of factor X to factor Xa represents a(n) _ form of activation; binding of antithrombin to thrombin represents a(n) _ form of inhibition.

Correct Answer
verified

Thrombin is similar to _ as it cleaves peptide bonds following _ residues.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
E

Correct Answer
verified
E

Correct Answer
verified

Correct Answer
verified

Thrombin circulates in the blood as a(n) _ that is called _.

Correct Answer
verified
zymogen, p...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified