Rates of enzyme-catalyzed reactions in the body are controlled by these principles: When more of a particular substance is needed, reaction rates _________; When a substance is not needed anymore, reaction rate _______.

The ability to control the rate of the overall metabolic pathway allows the cell to _____.

Catalyze the rate-limiting or slowest step in a pathway.

Enzyme rate depends on...

Regulation of enzyme activity is mediated by two mechanisms:

Select all of the following ways enzymes are regulated.

Effectors that non-covalently bind to an enzyme that cause conformational change.

Allosteric site on an enzyme is

Enzymes that usually have interactive subunits and have quaternary structure.

When the enzyme's substrate serves as an effector

When allosteric effectors are different from the enzyme substrate.

Homotropic effectors function mostly as

Presence of substrate in one active site enhances the catalytic properties at other substrate binding sites.

What type of effector exhibits positive cooperativity?

This allosteric effector plays an important role in feedback mechanisms where products from downstream reactions feedback and affect enzyme activity.

Which type of effector typically serves as allosteric inhibitors?

Allosteric enzymes usually have ____ subunits

Which substrate will have the most difficulty binding to the enzyme?

when the enzyme subunits are in a conformation with LOW affinity for the substrate

When an enzyme has a HIGH affinity confirmation for substrate.

The image best represents...

Where do activators bind on an allosteric enzyme?

An allosteric activator does what to an enzyme?

Allosteric activators bind at a site other than the active site.

Which confirmation would cause allosteric activators to bind more tightly?

Locks enzyme in the T state.

Allosteric inhibitors bind more tightly to

Which would make it MORE difficult for a substrate to its active site?

Which of the following would overcome the effects of an allosteric inhibitor?

Serve as rate limiting enzymes in metabolic pathways.

An allosteric effector needs to resemble the substrate or product of an enzyme.

Serve as allosteric activators of many enzymes involved in metabolic pathways.

ADP and AMP indicate

The effect of an allosteric effector is very fast.

Which type of enzyme is usually tissue specific?

Enzymes that catalyze the same reaction but have different physical properties and AA sequence.

Which of the following is an isozyme to glucokinase?

Found in skeletal muscle

found in the liver

Has low affinity for glucose and found in the liver.

has HIGH affinity for glucose and is found in RBCs, skeletal muscle, and most tissues.

have different kinetics but catalyze the same reaction.

Have different subunits depending on what tissue they are found in.

Either adding a phosphate or removing a phosphate.

Carry out phosphorylation (adds a phosphate)

Carries out dephosphorylation (removes a phosphate)

Transfer a phosphate group to the hydroxyl group of a specific tyrosine residue.

Select all that accurately describes a phosphate group.

Phosphorylation is irreversable.

Transfer a phosphate group from ATP to OH group of this amino acid on a target enzyme.

Phosphorylation and dephosphorylation is a slow process, often taking as long as 3 days.

What do kinases use as a source of phosphate groups?

Adding a phosphoryl group will....

Phosphoryl groups can form hydrogen bonds.

If an enzymatic process is "reversible" what does that mean?

Which AA are commonly phosphorylated?

How is glycogen phosphorylase activated?

How is glycogen phosphorylase inactivated?

What is the rate limiting enzyme in glycogen degradation?

Glycogen phosphorylase (rate limiting enzyme in glycogen degradation) can be summarized by: add phosphate to turn on, remove phosphate to turn off.

Which best describes a zymogen?

Proteolytic cleavage requires a lot of ATP.

After an enzyme undergoes proteolytic cleavage to be activated, it cannot be reversed back into a proenzyme.

The prefix "pro" and suffix "ogen" means...

Pepsinogen is the...

Zymogens are activated by

Which of the following is the active form?

Which of the following is the inactive enzyme?

How is chymotrypsinogen converted to a-chymotrypsin?