Chapter 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

substrate

Answer 4

the reactant of a reaction catalysed by an enzyme

Question 5

reactant

Answer 5

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

Question 6

product 

Answer 6

the transformed molecule created in a reaction

Question 7

active site

Answer 7

the part of an enzyme where the substrate binds

Question 8

enzyme-substrate complex

Answer 8

the structure formed when an enzyme and substrate are bound together

Question 9

conformational change 

Answer 9

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

Question 10

activation energy

Answer 10

the energy required to initiate a reaction

Question 11

collision theory

Answer 11

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

Question 12

biochemical pathway

Answer 12

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 13

optimal

Answer 13

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

Question 14

denature

Answer 14

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

Question 15

conformational change

Answer 15

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

Question 16

saturation point

Answer 16

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

Question 17

limiting factor

Answer 17

a factor that
prevents the rate of reaction from
increasing

Question 18

limiting reagent

Answer 18

a reactant that
prevents the rate of reaction from
increasing

Question 19

enzyme inhibitor

Answer 19

a molecule that
binds to and prevents an enzyme
from functioning

Question 20

competitive inhibition

Answer 20

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

Question 21

non-competitive inhibition

Answer 21

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 22

allosteric site

Answer 22

a region on an
enzyme that is not the active site

Question 23

reversible inhibition

Answer 23

enzyme inhibition that involves
weaker bonds that can be
overcome

Question 24

irreversible inhibition

Answer 24

enzyme inhibition that involves
stronger bonds that cannot be
broken

Question 25

biochemical pathway

Answer 25

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 26

cofactor

Answer 26

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

Question 27

coenzyme

Answer 27

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

Question 28

ATP 

Answer 28

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

Question 29

ADP

Answer 29

adenosine diphosphate,
the unloaded form of ATP

Question 30

anabolic reaction

Answer 30

two or more smaller molecules combine to form a larger one (i.e. building things up), uses energy

Question 31

catabolic reaction

Answer 31

larger molecule turning into two or more smaller molecules (i.e. breaking things down), releases energy