Protein Structure

Question 1

Structure of a protein

Answer 1

NH2, C00H and R group

Question 2

How many amino acids are there

Answer 2

20

Question 3

R group types

Answer 3

Non-polar aliphatic (hydrophobic)
Aromatic (hydrophobic and carbon ring)
Polar (uncharged and hydrophilic)
+ and - charged (hydrophilic at ph7)

Question 4

What is the primary structure

Answer 4

Sequence of amino acids linked by peptide bonds

Question 5

The primary structure is rigid and planar as

Answer 5

The bond has a partial double bond character

Question 6

Amino acids are folded into shape by

Answer 6

Electrostatic attractions, Hydrogen bonds, Vanderwall’s attractions and disulphide bonds

Question 7

What is a secondary structure

Answer 7

Beta pleated sheet, alpha helix, beta turns

Question 8

The beta sheet is either

Answer 8

Antiparallel- one up and one down from C to N and and vice versa
Parallel – hydrogen bonds form between chains

Question 9

Alpha helix has internal

Answer 9

Hydrogen bonds

Question 10

Beta turn Connect 

Answer 10

Secondary structures and make a kink in chain of beta sheets or alpha helix

Question 11

Tertiary structure is

Answer 11

3-D structure of folded protein

Question 12

The quaternary structure is

Answer 12

Several chains put together e.g. haemoglobin

Question 13

What is entropy

Answer 13

The measure of disorder

Question 14

The primary structure determines

Answer 14

The tertiary structure

Question 15

Proteins from generating a structure with the lowest

Answer 15

Free energy (entropy)

Question 16

What interactions are important in protein folding

Answer 16

Hydrophobic

Question 17

What drives folding and maintains the overall structure

Answer 17

Hydrophobic core

Question 18

What happens when a protein is unfolded

Answer 18

Hydrophobic collapse to form molten globule, internal core rearrangement to form native event

Question 19

Proteins are folded into multiple

Answer 19

Domains

Question 20

Domains have a specific function e.g.

Answer 20

DNA binding, spanning plasma membranes

Question 21

What does chaperones do in protein domains

Answer 21

Guide proteins to fold correctly

Question 22

What happens in protein denaturation

Answer 22

Solvents that break noncovalent interactions cause the protein to unfold
Some proteins recover and refold

Question 23

Protein mutations  are

Answer 23

A change in amino acid sequence which alters its tertiary structure and causes inherited disorders eg sickle cell anaemia

Question 24

What is a signal sequence

Answer 24

A group of an amino acid which determines where the proteins will go (ReR, golgi etc)
If there is no sequence then they will go to the cytosome