BIO 101: Homework Chapter 6

b

A noncompetitive inhibitor decreases the rate of an enzymatic reaction by a)decreasing the activation energy required for the reaction. b)changing the shape of the enzyme active site.

noncompetitive

A(n) ____ inhibitor binds to a site on the enzyme that is not the active site. active site competitive enzyme substrate noncompetitive irreversible

competitive

A(n) ____ inhibitor has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate. active site competitive enzyme substrate noncompetitive irreversible

c

An enzyme _____. a)increases the EA of a reaction b)can bind to nearly any molecule c)is an organic catalyst

a

As a result of its involvement in a reaction, an enzyme _____. a)is unchanged b)is used up

b

Cooperativity is a form of allosteric activation in which a)all of the enzymes in a metabolic pathway are contained within a single multienzyme complex. b)binding of a substrate molecule to one active site in a multisubunit enzyme stimulates the binding of substrate molecules to the active sites of other subunits.

substrate

Enzyme inhibitors disrupt normal interactions between an enzyme and its ___ active site competitive enzyme substrate noncompetitive irreversible

b

Enzymes work by _____. a)decreasing the potential energy difference between reactant and product b)reducing EA

b

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? a)saturation of the enzyme activity b)competitive inhibition

b

The active site of an enzyme is the region that a)is inhibited by the presence of a coenzyme or a cofactor. b)binds substrates for the enzyme.

catabolism

The cellular process of breaking down large molecules into smaller ones is defined as catabolism. anabolism.

anabolism

The cellular process of synthesizing large molecules from smaller ones is defined as catabolism. anabolism.

active site

The competitive inhibitor competes with the substrate for the___ on the enzyme. active site competitive enzyme substrate noncompetitive irreversible

c

The mechanism by which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as a)metabolic inhibition. b)noncooperative inhibition. c)feedback inhibition.

energy of activation

The red represents

irreversible

Usually, a(n)____ inhibitor forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity. active site competitive enzyme substrate noncompetitive irreversible

b

What name is given to the reactants in an enzymatically catalyzed reaction? a)active sites b)substrate

enzyme

When the noncompetitive inhibitor is bonded to the enzyme, the shape of the ___ is distorted. active site competitive enzyme substrate noncompetitive irreversible

ATP

Which is the highest energy form of adenosine?

b

Which of the following is an exergonic reaction? a)synthesis of ATP from ADP and i b)hydrolysis of glycogen to release glucose monomers

a

Which of the following is true for all exergonic reactions? a)The reaction proceeds with a net release of free energy. b)The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants.

a

Which of the following is true of enzymes? a)Enzymes increase the rate of chemical reaction by lowering activation energy barriers. b)Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.

b

Which of the following statements concerning catabolic pathways is true? a)They combine molecules into larger, more energy-rich molecules. b)They provide energy that can be used to drive cellular work.

c

Which of the following statements is representative of the second law of thermodynamics? a)Without an input of energy, organisms would tend toward decreasing entropy. b)Every energy transformation by a cell decreases the entropy of the universe. c)Cells require a constant input of energy to maintain their high level of organization.

b

Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions? a)β-phosphate (the middle phosphate) b)γ-phosphate (the terminal phosphate)

a

Which statement about the binding of enzymes and substrates is correct? a)When substrate molecules bind to the active site of the enzyme, the enzyme undergoes a slight change in shape. b)Substrate molecules fit into the active site of an enzyme like a key fits into a lock.