Ch 3 Enzymes

Question 1

enzyme

Answer 1

An organic molecule, typically a protein, that catalyses (speeds up) specific reactions.

Question 2

catalyst

Answer 2

A substance capable of increasing the rate of a reaction without being used up.

Question 3

catalyse

Answer 3

To increase the rate of a reaction.

Question 4

reactant

Answer 4

A molecule that undergoes a transformation into a product. When enzymes are involved, the reactant is called a substrate.

Question 4

substrate

Answer 4

The reactant of a reaction catalysed by an enzyme.

Question 5

product

Answer 5

The transformed molecule created in a reaction.

Question 6

active site

Answer 6

The part of an enzyme where the substrate binds.

Question 7

enzyme-substrate complex

Answer 7

The structure formed when an enzyme and substrate are bound together.

Question 8

conformational change

Answer 8

A change in the three-dimensional shape of macromolecules such as proteins.

Question 8

activation energy

Answer 8

The energy required to initiate a reaction.

Question 9

collision theory

Answer 9

Explanation of chemical reactions that states that in order to react molecules must hit one another.

Question 10

biochemical pathway

Answer 10

A series of enzyme-catalysed biochemical reactions in which the product of one reaction becomes the substrate of the next reaction. Also known as a metabolic pathway.

Question 11

denature

Answer 11

The disruption of a molecule’s structure by an external factor such as heat.

Question 12

optimal

Answer 12

The point at which for a given condition (e.g. temperature), the maximum function of an enzyme occurs. Also known as optimum.

Question 13

conformational change

Answer 13

A change in the three-dimensional shape of macromolecules such as proteins.

Question 14

limiting factor

Answer 14

A factor that prevents the rate of reaction from increasing.

Question 14

saturation point

Answer 14

The point at which a substance (e.g. an enzyme) cannot receive more of another substance (e.g. a substrate).

Question 14

limiting reagent

Answer 14

A reactant that prevents the rate of reaction from increasing.

Question 15

competitive inhibition

Answer 15

The hindrance of an enzyme by blocking the active site and preventing the substrate
from binding.

Question 15

enzyme inhibitor

Answer 15

A molecule that binds to and prevents an enzyme from functioning.

Question 16

allosteric site

Answer 16

A region on an enzyme that is not the active site.

Question 17

non-competitive inhibition

Answer 17

The hindrance of an enzyme by binding to an allosteric site and changing the shape of the active site to prevent the substrate from binding.

Question 17

reversible inhibition

Answer 17

Enzyme inhibition that involves weaker bonds that can be overcome.

Question 18

biochemical pathway

Answer 18

A series of enzyme-catalysed biochemical reactions in which the product of one reaction becomes the substrate of the next reaction. Also known as a metabolic pathway.

Question 19

irreversible inhibition

Answer 19

Enzyme inhibition that involves stronger bonds that cannot be broken.

Question 20

cofactor

Answer 20

Any organic or inorganic molecule, such as a coenzyme or metal ion, that assists enzyme function.

Question 20

coenzyme

Answer 20

A non-protein organic cofactor that assists enzyme function. They release energy and are recycled during a reaction.

Question 21

ATP

Answer 21

Adenosine triphosphate,
a high energy molecule that, when broken down, provides energy for cellular processes.

Question 22

ADP

Answer 22

Adenosine diphosphate, the unloaded form of ATP.