Proteins

Question 1

Polypeptides

Answer 1

Polymers made up of chains of amino acids

Question 2

Amino acid

Answer 2

Made up of an amino group, carboxyl group, hydrogen atom, and an R variable group
Which join together by a peptide bond

Question 3

Primary structure

Answer 3

Unique amino acid sequence

Question 4

Secondary structure

Answer 4

Shape of the polypeptide chain
Alpha helix or beta pleated sheet

Question 5

Tertiary structure

Answer 5

3D shape of the polypeptide
Secondary protein structures fold and twist to give more complex structures which are held together by hydrogen, ionic, disulphide bonds and hydrophobic interactions
Important in giving globular proteins (e.g. enzymes) their shape

Question 6

Quaternary structure

Answer 6

Proteins made up of 2 or more polypeptides

Question 7

Fibrous proteins

Answer 7

Long thing molecules that cross link to form lifters
Insoluble in water
E.g. Collagen - provides strength and toughness in tendons

Question 8

Globular proteins

Answer 8

Proteins that are compact and folded into spherical molecules
Soluble in water
E.g. enzymes, antibodies, plasma proteins, hormones
Haemoglobin - consists of four folded polypeptide chains with a haem group in the centre of each

Question 9

Test for proteins

Answer 9

Add Biuret reagent to solution and shake
Blue to purple precipitate

Question 10

Mutations (What happens when a change occurs in the base sequence?)

Answer 10

Changes the primary structure
Changes the secondary structure
Changes the tertiary structure
Bonding is affected
Has an effect on the globular/ fibrous structure of the protein