1.7, 1.8, 1.9: Enzyme Action

Question 1

Enzymes

Answer 1

Speed up chemical reactions by acting as biological catalysts

Question 2

Intracellular

Answer 2

within cells

Question 3

Extracellular

Answer 3

outside cells

Question 4

What are enzymes made of

Answer 4

Proteins

Question 5

Activation energy

Answer 5

A certain amount of energy is needed to be supplied to the chemicals before the reaction will start

Question 6

Enzymes … the activation energy

Answer 6

lower

Question 7

What does the active site bind to

what does it form

Answer 7

substrate

enzyme-substrate complex (ESC)

Question 8

reasons why ESC lowers actiation energy

Answer 8

= substrate molecules attached to the enzyme stay closer together which reduces any repulsion so they can bond more easily
=fitting into the active site puts a strain on the bonds in the substrate so they break up more easily

Question 9

Older enzyme model

Answer 9

Lock and key model

Question 10

New evidence to alter view of lock and key model

Answer 10

ESC changes shape slightly to complete the fit = locks the substrate even more tightly into the enzyme

Question 11

More recent enzyme model

Answer 11

Induced fit model

Question 12

Induced fit model

Answer 12

Helps to explain why enzymes are so specific and only bond to one substrate.
The substrate makes the active site change shape

Question 13

Tertiary structure of enzyme determines…

Answer 13

the shape of the active site

Question 14

Different enzymes have

Answer 14

different tertiary structures = different shaped active sites

Question 15

Alteration to tertiary structure of an enzyme means…

Answer 15

Shape o the active site changes
substrate won’t fit
no ESC
enzyme can’t carry out its function

Question 16

What affects the tertiary structure of enzymes

Answer 16

pH or temp changes

Question 17

How does a gene mutation affect the tertiary structure of the enzyme produced?

Answer 17

Gene mutation = amino acids sequence changes = primary structure different = tertiary structure different

Question 18

Competitive inhibitors

shape

Answer 18

Have a similar shape to substrate molecules

Question 19

Competitive inhibitors

how do they work

Answer 19

Compete with substrate molecules to bind to the active site but no reaction occurs and the active site is blocked

Question 20

Competitive inhibitors

Amount of enzyme inhibited

Answer 20

depends on relative concentrations of inhibitors and substrates

Question 21

Non-competitive inhibitors

Answer 21

Non-competitive inhibitors molecules bind to the enzyme away from its active site

Question 22

Non-competitive inhibitors

how do they work

Answer 22

Causes active site to change shape so substrate molecules can’t bind to it

Question 23

Non-competitive inhibitors

Amount of enzyme inhibited

Answer 23

Increasing substrate conc. won’t affect the ROR. = enzyme activity will still be inhibited

Question 24

Measuring the rate of an enzyme controlled reaction

2 methods

Answer 24

Measure hoe fast the product is made

Measure how fast the substrate is broken down

Question 25

Enzyme controlled reaction results show in

Answer 25

line graphs

Question 26

Calculating the initial rate of reaction

Answer 26

Tangent