topic 5 - protein function

Question 1

what is the function of proteins?

Answer 1

GLOBULAR PROTEINS:
Antibodies
Membrane channels
Enzymes
Mechanism
Kinetics
Regulation

FIBROUS PROTEINS:
Collagen
Silk

Question 2

what are the types of proteins?

Answer 2

Fibrous proteins create very long structures which provide structural integrity to biology.

Globular proteins are individual units and perform more ‘chemical’ tasks.

Question 3

what are globular proteins?

Answer 3

Enzymes transform chemicals through catalysis. Antibodies recognise foreign species and elicit an immune response. Membrane proteins transport chemicals and information across biological barriers.

Question 4

what do antibodies do?

Answer 4

1) Recognises antigen
2) Light chains
3) Heavy chains
4) Recognised by immune system

Question 5

what do membrane proteins do?

Answer 5

the membrane is hydrophobic.

Membrane proteins transport chemicals and information across biological barriers.

Question 6

what is the general mechanism of an Enzyme?

Answer 6

Enzymes are the body’s catalysts: agents that speed up reactions without being consumed.

• Enzymes provide a reaction environment
• They bring reactants together and position them correctly for optimum TS geomtery.
• Enzymes weaken bonds in the reactants.

Question 7

what is the step by step process of an Enzyme?

Answer 7

1. Substrates enter the active site.
2. Substrates are held in active site by weak interactions.
3. Active site can lower “EA” and speed up a reaction.
4. Substrates are converted to products.
5. Products are released.
6. Active site is available for two new Substrate molecules.

Question 8

Types of Enzyme reactions?

Answer 8

Role of Enzymes; different types of Enzymes.

Oxidoreductases = Oxidations and reductions

Transferases = Functional group transfer reactions

Hydrolases = Hydrolysis reactions

Lyases = Addition or removal of groups to form double bonds

Isomerases = Isomerisations and Intramolecular group transfers

Ligases = Joining two substrates at the expense of ATP hydrolysis

Kinases = Add phosphate groups to proteins, usually to activate them

Question 9

what are the function of each Fibrous protein?

Answer 9

Collagen = extacellular matrix
Elastin = Connective tissue
Keratin = Protection: skin, hair, nails and horn
Silk = Webs