ENZYME ACTION

Question 1

What are enzymes

Answer 1

globular proteins that act as biological catalysts for metabolic reactions

Question 2

Can enzymes be re-used?

Answer 2

yes

Question 3

What is a catalyst

Answer 3

substance that speeds up a chemical reaction without being used in the reaction itself

Question 4

What 2 types can enzyme action be

Answer 4

intracellular or extracellular

Question 5

What is intracellular

Answer 5

inside cells

Question 6

What is extracellular

Answer 6

outside cells

Question 7

Where do substrates bind to on enzymes

Answer 7

active site

Question 8

Can the active site change shape

Answer 8

yes

Question 9

Why are enzymes highly specific

Answer 9

due to their tertiary structure

Question 10

How do enzymes act as catalysts

Answer 10

lowering activation energy

Question 11

What is the activation energy

Answer 11

the minimum energy that reactions require before the reaction can start

Question 12

How does enzymes lowering activation energy mean reactions happen quicker and give and examples

Answer 12

they allow the reactions to take place at a lower temperature (e.g. metabolic reactions can occur rapidly at human body temp.)

Question 13

How 2 ways do enzymes lower activation energy

Answer 13

by forming an enzyme substrate complex, which:

1) means the substrates are held close together so repulsion between them is reduced and therefore can bond easier
2) puts a strain on the bonds in the substrate so it can be broken up easier

Question 14

How many models of enzyme substrate complex are there

Answer 14

2

Question 15

What are the models of enzyme substrate complex

Answer 15

lock and key , induced fit

Question 16

What is the lock and key model

Answer 16

each enzyme has a specific action site that fits a specific substrate exactly

Question 17

What is a limitation of the lock and key model

Answer 17

other molecules could bind to enzymes at other sites which altered the shape of the active site, meaning the active site was flexible

Question 18

What is the induced fit model

Answer 18

the active site forms as the enzyme and substrate interact, so the active site changes shape to fit around the substrate, which puts a strain on the bonds in the substrate. This lowers the activation energy

Question 19

What is the active site shape determines by

Answer 19

tertiary structure

Question 20

Which 3 ways can the tertiary structure be altered

Answer 20

changes in pH, changes in temperature, mutation in gene in primary structure