2.4 Cofactors & Coenzymes Flashcards Preview

A Level Biology > 2.4 Cofactors & Coenzymes > Flashcards

Flashcards in 2.4 Cofactors & Coenzymes Deck (30):
1

What are cofactors and coenzymes?

Non protein components of enzymes

2

What is a cofactor?

Inorganic molecule or ion

3

What does a cofactor do?

Helps enzymes carry out their functions

4

How might a cofactor help an enzyme?

• transferring atoms of groups between reactions
• form part of active site helping enzyme and substrate bind

5

Are cofactors used up or changed in the reaction?

No

6

How are cofactors bound to proteins?

Loosely

7

How do cofactors participate in catalysis?

By taking part in active site

8

What are coenzymes?

Organic

9

What does organic mean?

Contain carbon

10

Do coenzymes participate in reaction?

Yes

11

Are coenzymes changed in reaction?

Yes

12

What do coenzymes act as in the reaction?

Carriers
Moving chemical groups between enzymes

13

What are vitamins a source of?

Coenzymes

14

Give an example of a cofactor and what it is used for:

Cl- ions
Amylase requires them to form correctly shaped active site

15

What is the coenzyme Vit B5 used for?

To make coenzyme a used in breakdown of fatty acids and carbohydrates in respiration

16

What is the coenzyme Vit B3 used for?

To synthesise NAD - coenzymes responsible for transfer of H+ ions involved in respiration

17

What is a prosthetic group usually made of?

Mineral ion

18

How is a mineral ion bound to a protein?

Tightly

19

What do prosthetic groups form?

Permanent feature of protein

20

Zinc 2+ ions are a prosthetic group of what?

Carbonic anhydrase

21

What is carbonic anhydrase?

Enzyme in red blood cells
Catalysed production of carbonic acid from water and carbon dioxide

22

What do Zinc 2+ ions in carbonic anhydrase form?

Permanent part of active site

23

What is the prosthetic group of haemoglobin?

HAEM

24

How many polypeptide chains does haemoglobin have?

4

25

What does each polypeptide of haemoglobin have?

HAEM prosthetic group

26

What are inactive enzymes often called?

Inactive precursor enzymes

27

What are inactive precursor enzymes activated by?

Changes in tertiary structure particularly the active site

28

How is precursor activation ( change in tertiary structure) achieved?

Change in temp
Change in ph
addition of protease enzyme cofactor

29

What is an enzyme called before activation?

Apoenzyme

30

What is an enzyme called after activation with precursor?

Holoenzyme

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