4.7 Amino Acids, Peptides And Proteins

Question 1

What so a-amino acids consist of

Answer 1

Central a-carbon
Amino group
Carboxyl group

Question 2

How do amino acids exist as zwitterions

Answer 2

H+ from COOH group is gained by NH2

Question 3

Charge of zwitterions

Answer 3

Neutral

Question 4

What does zwitterions mean for the properties of amino acids

Answer 4

• solid at room temperature- have an ionic nature so can form strong ionic bonds
• ionic nature and so freely soluble in water

Question 5

What happens which amino acids dissolved in acidic solution

Answer 5

Gain protons
NH3+ and COOH

Question 6

What happens when amino acids are dissolved in basic solution

Answer 6

Lose a proton
NH2 and COO-

Question 7

What are 2 a-amino acids combined called

Answer 7

Dipeptides

Question 8

Role of proteins in living systems

Answer 8

• many functions eg structural, enzymes, growth, hormones

Question 9

Enzyme examples

Answer 9

Amylase in saliva catalyses hydrolysis of starch into sugars

Question 10

Why is the melting temperature of an amino acid much higher than other molecules of a similar size

Answer 10

As they can exist as zwitterions and so it has strong ionic character and therefore much stronger forces between molecules