Many Proteins Are Enzymes

Question 1

How do enzymes speed up a reaction

Answer 1

Provide an alternate pathway with a lower activation energy

Question 2

What type of catalyst are enzymes

Answer 2

Biological

Question 3

Are enzymes proteins

Answer 3

Yes

Question 4

What is the lock and key model

Answer 4

Shape of the active site doesn’t change when substrate binds

Question 5

What is the induced fit model

Answer 5

Tertiary structure of the enzyme changes as substrate approaches so active site fits around substrates

Question 6

What structure proteins are enzymes

Answer 6

Tertiary

Question 7

What is the key word to always through in for a mark when talking about enzymes

Answer 7

Enzyme substrate complex

Question 8

Explain in words
Temperature - rate of reaction increasing

Answer 8

Increasing kinetic energy of substrate and enzyme
Increases chance substrate collide with active site
Increase frequency = increase rate of reaction

Question 9

Explain in words
Temperature - optimum temperature

Answer 9

Maximum number of collisions between active site and enzyme

Question 10

Explain in words
Temperature - rate of reaction decreases
Enzymes

Answer 10

Higher temperature enzymes vibrating more rapidly
Causes bonds E.g. hydrogen bonds to break
Tertiary structure changes
Substrate no longer fits active site
Denatured

Question 11

Can a denatured enzyme return to original shape

Answer 11

No
Denaturing is permanent because tertiary structure changed

Question 12

What does the PH depend on

Answer 12

Concentration of H+ ions

Question 13

High PH has a …. Concentration of H+
Low PH has a …. Concentration of H+

Answer 13

Low
High

Question 14

What happens if PH is do low or high on enzyme detailed x3

Answer 14

Interfere with the charges in amino acid
This breaks bonds changing tertiary shape of enzyme
Change active site

Question 15

What does a competitive inhibitor do

Answer 15

Similar shape to substrate
Bonds to active site and occupies it
Prevents substrate from binding

Question 16

How to reduce effect of competitive inhibitor

Answer 16

Increase substrate

Question 17

Does a reaction happen with a competitive inhibitor

Answer 17

No
It’s not the substrate

Question 18

How do non-competitive inhibitors work

Answer 18

Bind to allosteric site
Tertiary structure of enzyme changes - active site changes no longer complementary to substrate
Less enzyme-substrate complex’s formed

Question 19

How to limit effect of non-competitive inhibitor

Answer 19

Increasing substrate has NO effect
Can’t do anything

Question 20

Why is an answer given to a whole number when using a ruler to measure

Answer 20

Reduces uncertainty

Question 21

Describe how an enzyme can be phosphorylated

Answer 21

Attachment of a phosphate
Released from hydrolysis of ATP

Question 22

Explain how the active site of an enzyme causes a high rate of reaction.

Answer 22

Lowers activation energy
Induced fit causes active site of enzyme to change
So enzyme-substrate complex causes bonds to break

Question 23

Formation of enzyme-substrate complex increases rate of reaction
Explain how x2

Answer 23

Lowers activation energy
Due to bending bonds
( because of induced fit model the bonds have to bend to fit around substrate)

Question 24

Explain how chemical X binding to an enzyme could increase the rate of reaction

Answer 24

( if it is increasing rate of reaction it is NOT an inhibitor)
Binding alters tertiary structure of enzyme
This cause active site to change shape
More Enzyme-substrate complexes formed