Protiens

Question 1

What is formed when amino acids are joined by condensation reactions

Answer 1

Polypeptides

Peptide bond

Question 2

Explain the 4 structural levels of a protein

Answer 2

Primary structure- sequence of amino acids
Secondary structure- hydrogen bonds form between the amino acids to make alpha helix or beta pleated sheet
Tertiary structure- folded or coiled further
Hydrogen bonds, ionic bonds (pos and neg) disulphide bridges, cysteine sulphur to sulphur
Quaternary structure- different polypeptide chains held together by bonds 3D structure

Question 3

What are the 4 functions of proteins and give an outline?

Answer 3

Enzymes- spherical in shape due to tightly folding, metabolism
Antibodies- immune response, two light two heavy, amino acids vary greatly
Transport proteins- channel proteins, transport ions
Structural protiens- strong long polypeptide chains, lying parallel with cross links, keratin and collagen

Question 4

What is the test for protiens

Answer 4

Needs to be alkaline so add sodium hydroxide solution
Add copper sulphate
Protien= purple
No protein stay blue

Biuret test

Question 5

Describe the structure of amino acids?

Answer 5

Amine group to C to carboxyl group  have R group and hydrogen coming off the carbon
         R
          |
H2N-C-COOH
          |
         H

R group is variable contains carbon