Levels of protein structure

Question 1

Define: primary structure

Answer 1

specific linear sequence of amino acids in a pp.

Question 2

what determines primary structure?

Answer 2

base sequence in a gene

Question 3

Define: secondary structure

Answer 3

localised folding and coiling of segments

Question 4

what causes secondary structure?

Answer 4

Hydrogen bonds between NH group (partially positive) and CO group (partially negative)

Question 5

describe 3 main shapes of secondary structure?

Answer 5

alpha helix (h bonds result in spirals)
beta pleated sheets (two or more parts of pp chain line up and hydrogen bonds form)
random coiling

Question 6

Define: tertiary structure

Answer 6

specific overall 3d shae of a protein

Question 7

what is tertiary structure caused by?

Answer 7

interactions between R groups (hydrogen bonding, ionic bonding, disulphide bonds between cysteine aa’s and hydrophobic interactions (go inside))

Question 8

Define: quaternary structure

Answer 8

structure in which 2 or more chains interact

Question 9

What is the functional importance of the four hierarchical levels of protein structure?

Answer 9

Interactions at each level determine the protein’s shape, and therefore its function.