Elements Of Protein Structure

Question 1

Non polar amino acids

Answer 1

Side chains involved in hydrophobic interactions
Tend to cluster in the interior of the protein within a hydrophilic environment, found on outside surface in membrane proteins as surface is hydrophobic

Question 2

Polar amino acids

Answer 2

Side chains have an uneven distribution of charges

Question 3

Acidic amino acids

Answer 3

At pH 7.4 these amino acids are proton donors

Their carboxylic group is fully ionised and they contain negatively charged carboxylic group - EXTREMELY HYDROPHILIC

Question 4

Basic amino acid

Answer 4

Side chains of these amino acids accept protons and the amino groups are positively charged

Question 5

Primary structure

Answer 5

Corresponds to the sequence of amino acids

Question 6

Genetic diseases due to

Answer 6

Disruptions in primary structure which causes misfolding and loss of function to the protein

Question 7

Characteristics of a peptide bond

Answer 7

Partial double-bond character
Rigid and planar
Trans configuration
Uncharged but polar

Question 8

Alpha helix

Answer 8

A right handed spiral confirmation consisting of tightly packed coil backbone of amino acids with their side chains extending outwards

Question 9

Tertiary structure

Answer 9

The final folding of a polypeptide formed by a sequential combination of different types of secondary structures - stabilised by hydrophobic interactions between non polar amino acids

Question 10

Incorrect protein folding

Answer 10

Makes the protein lose function and can make proteins sticky - so more likely to form aggregates which correlates with a risk of disease specifically neurodegenerative disease

Question 11

Quaternary structure

Answer 11

The arrangement of several similar or unrelated polypeptide subunits
Can function independently or in a cooperative manner

Question 12

Haemeproteins

Answer 12

Globular protein which contain a haeme group as a tightly bound prosthetic group

Question 13

Myoglobin

Answer 13

Present in the heart and skeletal muscles

Functions as a reservoir and carrier of oxygen

Question 14

Haemoglobin

Answer 14

Found exclusively in red blood cells where its main function is to transport oxygen from the lung to the capillaries of the tissues of the body
Can also transport H+ and CO2 in the opposite direction

Question 15

Composition of haemoglobin

Answer 15

Composed of four polypeptide chains - 2 alpha and 2 beta held together by non covalent interactions

Question 16

Collagen

Answer 16

Fibrous protein with long rigid structure in which three polypeptides are wound round each other in a rope like a triple helix

Question 17

Fibrillation forming collagen

Answer 17

Have rope like structure - type 1,2 and 3

Question 18

Type 1 collagen

Answer 18

Found in tendons and cornea - contains two alpha 1 chains and one alpha 2 chain

Question 19

Type 2 collagens

Answer 19

Are restricted to cartilaginous tissues - contain three alpha 1 chains

Question 20

Type 3 collagens

Answer 20

Prevalent in more distensible tissues such as blood vessels

Question 21

Network forming collagens

Answer 21

Form mesh type 4 collagen and is a component of the basement membrane