Unit 1 - Chapter 2 Role of Enzymes

Question 1

Enzymes are biological

Answer 1

catalysts

Question 2

Catalysts speed up chemical reactions without being

Answer 2

affected themselves

Question 3

When enzymes build up large molecules it is called a

Answer 3

synthesis reaction

Question 4

When enzymes break down large molecules it is called a

Answer 4

degradation reaction

Question 5

An active site of an enzyme is specific to only one

Answer 5

substrate

Question 6

Enzymes are made of protein so are affected by

Answer 6

temperature and pH

Question 7

At a low temperature there are few collisions between

Answer 7

substrate and enzymes so the reaction is low

Question 8

As temperature increases so does

Answer 8

the rate of reaction

Question 9

The reaction rate reaches its maximum when the temperature reaches

Answer 9

optimum

Question 10

At a temperature past optimum the enzyme protein begins to

Answer 10

denature

Question 11

Enzymes are active within a narrow ph

Answer 11

range

Question 12

Most enzymes have an optimum pH which is

Answer 12

neutral or slightly alkaline

Question 13

The exception to the optimum pH is pepsin which has an optimum of

Answer 13

pH 2

Question 14

Enzymes control biochemical pathways both

Answer 14

inside and outside the cell

Question 15

Essential metabolic pathways can be stopped if a mutation

Answer 15

codes for an ‘enzyme’ of the wrong shape

Question 16

PKU is an example of a

Answer 16

inherited disorder

Question 17

PKU is when an essential metabolic pathway is

Answer 17

prevented by the absence of an enzyme

Question 18

The activity of an enzymes increases as the substrate

Answer 18

concentration increases

Question 19

Substrate concentration gives a reaction rate increase until

Answer 19

all the active sites are working at their maximum rate

Question 20

The rate of reaction increases as the enzyme concentration increases as

Answer 20

there are more active sites for substrate molecules.

Question 21

A competitive enzyme inhibitor has a similar shape to the

Answer 21

substrate and so competes for the active site of the enzyme

Question 22

As the proportion of competitive inhibitor to substrate increase the

Answer 22

rate of reaction decreases

Question 23

A non competitive enzyme inhibitor binds to the enzyme permanently and changes the shape of the

Answer 23

active site which prevents substrate molecules from binding.

Question 24

A non competitive inhibitor produces

Answer 24

non functional enzymes

Question 25

Non-competitive inhibitors reduce the rate of reaction whatever the

Answer 25

substrate concentration

Question 26

An example of non-competitive inhibition is

Answer 26

lead

Question 27

Lead is a non-competitive inhibitor which

Answer 27

slows down the reaction rate of the enzyme catalase

Question 28

Many enzymes depend on co-factors such as

Answer 28

mineral ions or vitamins

Question 29

Digestive enzymes for example Trypsin are converted from

Answer 29

inactive to active state by another enzyme

Question 30

Vitamins are used to make co-enzyme molecules essential for

Answer 30

the activity of some enzymes e.g. the hydrogen acceptor NAD

Question 31

A variety of mineral ions are essential cofactors to activate

Answer 31

a number of enzymes e.g. iron in catalase