1.6 proteins

Question 1

describe the structure of an amino acid.

Answer 1

NH2CHRCOOH

Question 1

how are polypeptide chains formed from an amino acid?

Answer 1

join by condensation reaction to form a peptide bond

Question 2

how many amino acids are there in all living things?

Answer 2

20

Question 3

describe the primary structure of amino acids.

Answer 3

amino acid sequence in the polypeptide chain

Question 4

describe the secondary structure of amino acids.

Answer 4

polypeptide chains form alpha-helices & beta-pleated sheets due to hydrogen bonding from the main chain

Question 5

describe the tertiary structure of amino acids.

Answer 5

folding & twisting the polypeptide chain into a complex & specific shape.
forms ionic bonds, hydrogen bonds & disulfide bridges

Question 6

describe the quaternary structure of amino acids.

Answer 6

several polypeptide chains join together / attach a non-protein group

Question 7

what is the test for proteins?

Answer 7

biuret

Question 8

describe how the biuret reagent detects proteins and the test result.

Answer 8

reagent detects peptide bonds
- lilac if positive, blue if negative