Question 1

Part of the structure of a protein is shown.

How many different amino acids were used to form this part of the structure?

  A  

3

  B  

4

  C  

5

  D  

6

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Question 2

Glycine and alanine are the two simplest amino acids.

Glycine and alanine combine to form two possible dipeptides.

What are the structures of these dipeptides?

  A  

H2NCH2COONHCH(CH3)COOH and H2NCH(CH3)COONHCH2COOH

  B  

H2NCH2CONHCH(CH3)COOH and H2NCH(CH3)COONHCH2COOH

  C  

H2NCH2COONHCH(CH3)COOH and H2NCH(CH3)CONHCH2COOH

  D  

H2NCH2CONHCH(CH3)COOH and H2NCH(CH3)CONHCH2COOH

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Question 3

The best method for separating a mixture of amino acids in solution, for the purpose of identification, is

  A  

recrystallisation

  B  

distillation

  C  

chromatography

  D  

solvent extraction

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Question 4

Chromatography may be used to separate mixtures of amino acids. This is best explained by the fact that different amino acids have different interactions with

  A  

the mobile phase only

  B  

the stationary phase only

  C  

the mobile phase and the stationary phase

  D  

ninhydrin

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Question 5

Which statement about DNA is not true?

  A  

DNA is a condensation polymer

  B  

adenine and uracil join by 2 hydrogen bonds in DNA

  C  

guanine and cytosine join by 3 hydrogen bonds in DNA

  D  

the backbone of DNA is made of phosphate and deoxyribose

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Question 6

Which statement describes the secondary structure of a protein?

  A  

the types of amino acids present

  B  

the sequence of the amino acids


  C  

attractions between groups causing folding of the protein helix


  D  

hydrogen bonds causing a helix or sheet

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