Unit 1.2.c.i

Question 1

What are proteins polymers of?

Answer 1

Amino acid monomers

Question 2

Amino acids are linked by (1) to form (2)

Answer 2

1. Peptide bonds

2. Polypeptides

Question 3

What are R-groups?

Answer 3

Amino acids have the same basic structure, differing only in the R group present

R groups of amino acids vary in size, shape, charge, hydrogen bonding capacity and chemical reactivity

Question 4

What are the 4 categories amino acids can be classified by?

Answer 4

Basic (positively charged)
Acidic (negatively changed)
Polar (will mix with water ie hydrophilic)
Hydrophobic (will not mix with water ie non-polar)

Question 5

Give an example of a basic group

Answer 5

Amine group

H
    \
      N-
    /
H

Question 6

Give an example of an acidic group

Answer 6

Carboxylic acid group

    O
   //
-C
    \
     OH

Question 7

Give an example of a polar group

Answer 7

Has nitrogen or oxygen ( N or O) in the R group

Question 8

Give an example of a hydrophobic group

Answer 8

Has Carbon or hydrogen (C or H) in the R group

Question 9

What does the R group of an amino acid allow?

Answer 9

The wide range of functions carried out by proteins results from the diversity of R groups

Question 10

What is the primary structure?

Answer 10

The sequence in which the the amino acids are synthesised into the polypeptide

Question 11

How are secondary structures formed?

Answer 11

Hydrogen bonding along the backbone of the protein strand results in regions of secondary structures

Question 12

Give examples of secondary structures

Answer 12

Alpha helixes, parallel or anti-parallel beta-pleated sheets, or turns

Question 13

What do polypeptides fold into?

Answer 13

Tertiary structures

Question 14

How are conformations stabilised?

Answer 14

Interactions between R groups

Question 15

Give examples of the interactions between R groups

Answer 15

Hydrophobic interactions, ionic bonds, London dispersion forces, hydrogen bonds, disulfide bridges

Question 16

What is a quaternary structure?

Answer 16

Quaternary structure exists in proteins with 2 or more connected polypeptide subunits

Quaternary structure describes the spatial arrangement of the subunits

Question 17

What is a prosthetic group?

Answer 17

A non-protein unit tightly bound to a protein and necessary for its function

Question 18

Give an example of a prosthetic group?

Answer 18

The ability of haemoglobin to bind oxygen is dependent upon the non-protein harm group

Question 19

How can temperature and pH influence the interactions of the R groups

Answer 19

A decrease in pH or an increase in temperature lowers the affinity of haemoglobin for oxygen, so the binding of oxygen is reduced. Reduced pH and increased temperature in actively respiring tissue will reduce the binding of oxygen to haemoglobin promoting increased oxygen delivery to tissue.