Uml Biochemistry Enzyme Regulation

Front 1

Factors that influence enzyme activity:
~Rate slows as _________ accumulates.
~Rate depends on substrate availability.
~Genetic controls - induction and repression
~Allosteric regulation

Back 1

product

Front 2

Allosteric regulators (general features): Enzymes situated at key steps in metabolic pathways are modulated by allosteric effectors.
Effectors may be feed-forward activators or feedback inhibitors.
Kinetics are sigmoid ("S-shaped")

Back 2

Sigmoid means cooperative binding of S!

Front 3

Multiple substrate enzyme reactions are divided into two classes:
A) sequential displacement and double displacement.
B) double displacement and concerted displacement.
C) sequential displacement and ping-pong.
D) a and c.
E) None of the above.

Back 3

D) sequential, double and ping-pong

Front 4

What type(s) of inhibition can be reversed?
A) competitive
B) noncompetitive
C) mixed
D) All of the above
E) None of the above

Back 4

D) "Unless it's covalent, it's reversible"

Front 5

Km is _______.
A) the substrate concentration at ½ Vmax.
B) = (k-1 + kcat)/k1
C) related to an enzymes affinity for a specific substrate.
D) the Michaelis Constant.
E) All of the above

Back 5

E)

Front 6

Enzymes have active sites which have the greatest complementarity to the:
A) substrate.
B) transition state.
C) product.
D) both substrate and product.
E) none of the above.

Back 6

B) transition state (if it binded S more tightly, it would lock up)

Front 7

Regulatory enzymes show different kinetics (from typical enzymes). Their plots are ___________ rather than ___________.

Back 7

sigmoid; hyperbolic

Front 8

Glycogen PhosphorylaseAllosteric Regulation and Covalent Modification:
Pi is a ___________ homotropic effector;
ATP is a ______________ inhibitor, and a negative heterotropic effector;
Glucose-6-P is a negative heterotropic effector (i.e., an _________);
AMP is a positive heterotrophic effector (i.e., an ______________)

Back 8

positive ; feedback ; inhibitor; activator

Front 9

Cyclic AMP is the intracellular agent of extracellular hormones - thus a "__________________"

Back 9

second messenger