1.7 Enzymes

Question 1

Cellular activity of all living things is controlled
using

Answer 1

Enzymes

Question 2

Enzyme

Answer 2

Biological catalyst that speeds up chemical reactions without being consumed in the reaction

Most enzymes are PROTEINS

Question 3

… Break down/Build up molecules

Answer 3

Enzymes

Question 4

Have very specific shapes and ONLY react with
specific substances

Answer 4

Enzymes

Ex. Lactase with only catalyse Lactose

Question 5

Enzymes bind to a
specific reactant (or
reactants)

Answer 5

Called a SUBSTRATE

Question 6

Substrate only interacts with a small region of
the enzyme called the…

Answer 6

Active site

Question 7

Induced-Fit Hypothesis:

Answer 7

prior to the substrate binding, the enzyme changes its shape slightly, so that the active site becomes even more precise in its ability to bind

Question 8

Term used to describe the enzyme + substrate structure

Answer 8

Enzyme-Substrate Complex

Question 9

Cofactor

Answer 9

Non-protein group that
binds to enzymes and helps them function

Often metals such as copper, iron, zinc

Question 10

Coenzyme

Answer 10

an organic molecule that acts as a cofactor of an enzyme

may be derived from vitamins

Question 11

If excess substrate

Answer 11

the rate
of reaction is proportional to
the enzyme concentration

This occurs because the amount of enzyme limits the rate of reaction

Question 12

If amount of enzyme is at a constant concentration,

Answer 12

then increasing the substrate will increase the rate of reaction to a point, called the saturation level

Increasing substrate will have a
reduced effect

At the saturation level, the enzyme molecules are saturated with substrate

Question 13

Enzyme Inhibitors

Answer 13

Bind to enzymes to inhibit activity

May be reversible or irreversible

Question 14

Competitive Inhibitor

Answer 14

binds to active site to prevent substrate from binding

Question 15

Non-competitive Inhibitor

Answer 15

binds to enzyme and changes its shape, indirectly preventing the substrate from binding

Question 16

Allosteric Regulation

Answer 16

regulation of enzyme function using other molecules that bind to the enzyme

Question 17

Allosteric Site

Answer 17

a binding site on an enzyme (NOT the active site) where allosteric molecules
attach, which cause a change in the shape of the enzyme

Question 18

Allosteric Inhibition

Answer 18

stabilizes enzyme into an inactive form

Question 19

Allosteric Activation

Answer 19

stabilizes enzyme into an active form

Question 20

Feedback Inhibition

Answer 20

The regulation of a pathway by one of the products of the pathway

If the product accumulates in excess, its effect as an inhibitor slows/stops the enzymatic reaction that produces it

If the product is scarce inhibition is reduced, and rate of reaction increases

Essentially once enough product is produced then the pathway shuts down until more product is needed