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University of Central Florida FIL 1000 Ch 7 Quiz 1)A velocity curve (V vs

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University of Central Florida

FIL 1000

Ch 7 Quiz

1)A velocity curve (V vs. [S]) for a typical allosteric enzyme will be Select one:

a.            a rectangular hyperbola. b. a sigmoid curve.

c.             a straight line.

d.            a parabola.

e.            none of these

 

2.            Acyl transfer reactions often use this cofactor: Select one:

a.            Riboflavin b. Lipoic acid

 

c.             Pyridoxal

d.            Thiamine

e.            Biotin

 

3.            Cofactors are Select one:

a.            non-protein in chemical nature.

b.            always small proteins.

c.             modified amino acids.

d.            never required for enzymatic activity.

 

4.            In the concerted model for allosteric enzymes Select one:

a.            the relative affinities of substrate for the T and R conformations plays an important role in the cooperativity of the reaction.

b.            the equilibrium between the T and R conformations plays a minor role.

c.             the enzymatic activity of the T conformation is considerably higher than that of the R form.

d.            it is possible to describe the reactions of all allosteric enzymes accurately.

 

5.            In zymogen activation Select one:

a.            only digestive enzymes are involved.

b.            a conformational change takes place with no alteration of primary structure. c. an inactive protein is converted to an active one by bond cleavage.

d. there is aggregation of several enzyme molecules when the substrate binds.

 

 

 

 

 

 

6.            Kinase reactions describe enzymes which Select one:

a.            add phosphate groups to another molecule.

b.            oxidize alcohols to aldehydes.

c.             use NAD+/NADH in their reactions.

d.            transfer groups from one part of a molecule to another.

e.            add or remove double bonds in molecules.

 

7.            Phosphorylation of enzymes Select one:

a.            has no effect on their catalytic activity.

b.            does not require ATP.

c.             usually takes place on serine, threonine, and tyrosine residues.

d.            always increases the activity of the enzyme

 

 

8.            The active site of chymotrypsin contains all of the following, except: Select one:

a.            Histidine residue. b. A magnesium ion.

c.             Hydrophobic pocket to bind the substrate.

d.            Serine residue.

e.            All of these are in the active site of chymotrypsin.

 

9.            The term K0.5 is analogous to the KM Select one:

a.            True

b.            False

 

10.          Which of the following is NOT required in order for an enzyme to display cooperative kinetics?

Select one:

a.            Multiple subunits.

b.            A value for the Michaelis constant, KM.

c.             Allosteric sites which affect the binding of substrate to the active site.

d.            Ability to display a Vmax.

e.            All of these are characteristic of cooperative enzymes.