proteins

Question 1

What is a protein?

Answer 1

Polypeptide made of many amino acids

there are 20 different amino acids in humans but 500 over all

Question 2

describe an amino acid

Answer 2

• amino group made of two hydrogen and one nitrogen attached to a carbon
• a hydrogen attached to central carbon
• an R group attached to central carbon
• a carboxyl group attached to central carbon made of a carbon double bonded to an oxygen and an OH group

Question 3

What makes up the primary structure of a protein?

Answer 3

the sequence of amino acids

Question 4

What makes up the secondary structure of a protein?

Answer 4

• The coiling and folding of the amino acid chain into alpha pleats, beta pleats or unstructured folding
• held together by hydrogen bonding
• therefore susceptible to changes in pH and temp

Question 5

What makes up the tertiary structure of a protein?

Answer 5

• the folding of the secondary structure into a 3D shape

- held together by ionic bonds, hydrogen bonds and disulphide bridges

Question 6

What makes up the quaternary structure of a protein?

Answer 6

• the order of the polypeptide chains

Question 7

what is the biuret test?

Answer 7

• Add equal volume of copper (II) sulphate and sodium hydroxide to test
• shake to combine
• if it forma a purple layer then it is positive
• negative stays blue