Proteins

Question 1

Proteins are made of

Answer 1

Amino acids
Amino acids are made of C, H, O, N, (S)

Question 2

How are dipeptides formed

Answer 2

2 amino acids joined together between the OH from carboxyl group and H from amino group by peptide bonds in a condensation reaction

Question 3

How does one amino acid differ from another

Answer 3

They have different R groups

Question 4

Primary structure

Answer 4

A sequence of amino acids joined by peptide bonds

Question 5

Secondary structure

Answer 5

Occurs when the sequence of amino acids are linked by hydrogen bonds between the carbonyl groups and amino groups in the polypeptide backbone to form alpha helices and beta pleated sheets

Question 6

Tertiary structure

Answer 6

Complex folding of the polypeptide
Hydrogen, ionic, disulphide bonds between R groups
Tertiary structure depends on primary structure

Question 7

Quaternary structure

Answer 7

More than one polypeptide chain
Hydrogen, ionic and disulphide bonds
Globular proteins or fibrous proteins

Question 8

Biochemical test for proteins

Answer 8

Add biuret reagent to sample
Positive result will be a lilac colour

Question 9

Two proteins have same number and type of amino acids but different tertiary structures. Explain how

Answer 9

Different primary structure (order of amino acids)
Forms hydrogen, ionic, disulphide bonds in different places