PROTEINS PMT FLASHCARDS

Question 1

What is the general structure of amino acid?

Answer 1

-COOH carboxyl/carboxylic acid group
-R variable side group consists of carbon chain and may include other functional groups e.g benzene ring or -OH(alcohol)
-NH2 amine / amino group

Question 2

describe how to test for proteins in a sample

Answer 2

biuret test confirms presence of peptide bond
1)add equal volume of sodium hydroxide to sample at room temperature
2)add drops of dilute copper sulphate solution.swirl and mix
3.positive result=colour changes from blue to purple
negative result=solutions remains blue

Question 3

how many amino acids are there and how do they differ from one another

Answer 3

20 and they differ by the R group

Question 4

how do dipeptides and polypeptides form?

Answer 4

condensation reaction forms peptide bond(-COHN-) and eliminates molecule of water
-dipeptides:2 amino acids
-polypeptides:3 or more amino acids

Question 5

how many levels of protein structure are there

Answer 5

4

Question 6

define primary structure of a protein

Answer 6

sequence , number and type of amino acids in the polypeptide
-determined by sequence of codons on mRNA

Question 7

define secondary structure of a protein

Answer 7

hydrogen bonds form between O (slightly negative) attached to C=O&H (slightly positive) attached to -NH

Question 8

Describe the 2 types of secondary protein structure