Question 1

Which level of organisation of a haemoglobin molecule is coded by a DNA molecule?

  A  

primary structure

  B  

secondary structure

  C  

tertiary structure

  D  

quaternary structure

0

/

1

Question 2

The diagrams show the structures of two amino acids, each of which has two amine (–NH2) groups.

A peptide bond is formed between the two amino acids.

Which groups form the peptide bond?

  A  

1 and 4

  B  

1 and 5

  C  

2 and 6

  D  

3 and 5

0

/

1

Question 3

Which statements about a peptide bond are correct?

1 - it joins two monomers that are always identical to each other

2 - it contains four different atoms

3 - it can be broken by the addition of water at room temperature

4 - it is important in the primary structure of proteins

  A  

1, 2, and 3

  B  

1 and 3 only

  C  

2, 3, and 4

  D  

2 and 4 only

0

/

1

Question 4

Which statements about the primary structure of a protein are correct?

1 - it may be branched

2 - it is determined by the sequence of DNA bases

3 - it is unique to that protein

4 - it determines the tertiary structure of the protein

  A  

1, 2, and 3

  B  

1, 2, and 4

  C  

1, 3, and 4

  D  

2, 3, and 4

0

/

1

Question 5

What could describe the tertiary structure of a protein?

1 - α-helix

2 - a globular structure

3 - the specific order of amino acids

4 - a specific three-dimensional (3D) shape

  A  

1, 2, and 3

  B  

1, 2, and 4

  C  

2 and 4 only

  D  

3 and 4 only

0

/

1

Question 6

A conjugated protein is held together by many different types of bond.

Which bond is not formed when a conjugated protein folds into its quaternary structure?

  A  

disulphide

  B  

hydrogen

  C  

ionic


  D  

peptide


0

/

1

Question 7

Which feature of haemoglobin makes it a globular protein?

  A  

it has four cross-linked polypeptide chains forming a quaternary structure

  B  

it has hydrophobic groups on the inside and hydrophilic groups on the outside

  C  

it has hydrophobic interactions and is insoluble in water

  D  

it has polypeptide chains which are cross-linked to form sheets. 

0

/

1

Question 8

Which is the strongest type of bonding found in proteins?

  A  

disulfide bonds

  B  

hydrogen bonds

  C  

hydrophobic interactions

  D  

ionic bonds

0

/

1

Question 9

Which description is correct?

  A  

a collagen molecule has a high proportion of the amino acid glycine, which has a very small side chain

  B  

a group of three collagen fibres forms a strong, insoluble coiled structure termed a triple helix

  C  

each of the collagen polypeptides in a collagen molecule has a regular spiral arrangement of many alpha helices

  D  

peptide bonds are present between amino acids of the same polypeptide and between the different polypeptides forming the collagen molecule

0

/

1

Question 10

Collagen is found in tendons. Tendons attach muscles to bones.

Which properties make collagen suitable for this role?

  A  

strong, inflexible, insoluble

  B  

strong, flexible, soluble

  C  

strong, inflexible, soluble


  D  

strong, flexible, insoluble

0

/

1

Question 11

Haemoglobin consists of two α chains and two β chains. Approximately 5% of all humans have one amino acid in the β chain that has been changed, affecting the structure and stability of haemoglobin.

Which of the levels of protein structure could be changed in the haemoglobin of these humans?

  A  

primary only

  B  

primary and quaternary only

  C  

primary, secondary, tertiary, and quaternary

  D  

secondary, tertiary, and quaternary only

0

/

1

Question 12

Lysozyme is an enzyme found in tears and saliva.

Which statement refers only to the tertiary structure of lysozyme?

  A  

a section of the molecule consists of an α-helix

  B  

it consists of a single polypeptide

  C  

it is 129 amino acids long

  D  

the 35th and 52nd amino acids help form the active site

0

/

1

Question 13

The diagram below is a chromatogram of three different amino acids. The distance travelled by the solvent from the baseline is 50 mm.

Using the information in the chromatogram, which option is the Rf value for the amino acid leucine (Leu)?

  A  

0.39

  B  

0.28

  C  

0.72

  D  

1.39

0

/

1