LEC05

Question 1

List the 7 different functions of proteins.

Answer 1

1. Structural support (collagen for skin and bones)
2. Storage (caesin the amino acids in milk)
3. Transport (haemoglobin for oxygen transport)
4. Hormonal regulation (insulin for sugar control)
5. Movement (actin/myosin for muscle contractions)
6. Defence (immunoglobulin for infections)
7. Enzymes (catalysing reactions)

Question 2

What is an enzyme and its functions? Also give an example.

Answer 2

• A protein that catalyses (speeds up) chemical reactions
• Normally ends in -ase
• Digestion
• Making DNA, proteins, carbs
• Protein processing (activation of pro-insulin, pro-collagen)
• Trims proteins for catalysis

E.g. sucrase breaks sucrose into glucose and fructose through hydrolysis.

Question 3

What does Kcat mean?

Answer 3

Indicates how fast a single enzyme can convert substrate to product. Catalase is very quick.

Question 4

What does Km mean?

Answer 4

Affinity of the substrate for the enzyme (how likely they are to engage), the lower the number, the better.

Question 5

What is pKa?

Answer 5

The equilibrium constant for an acid base equilibrium, the p indicates it’s on a logarithmic scale (log10).

Question 6

How does pH affect amino acids?

Answer 6

The charges change.

Question 7

Draw an amino acid.

Answer 7

Look at onenote.