Name: _______________________________________________ 	

  	
  	
Topic 2 Genes & Health	
 
Plasma membrane, Protein, DNA replication, Mutation
 	
Date:	

  	
  	
Time: 30 minutes 	
  	
Total marks available: 27 	
  	
Total marks achieved: ______ 	

  	

  	

  	

  	

  	

  	

  	
Data analysis focus 	

	

Questions

Q1.
 
Molecules are transported across the cell membrane in a number of different ways.
(a) Describe the structure of a cell membrane.
(3)
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(b) Cells were placed in a solution containing two different solutes, solute P and solute R.
The diagram below represents the concentration of the two solutes outside one of the cells, when this cell was placed in the solution.

The cells were left in the solution for 50 minutes.
The diagrams below represent the concentrations of the two solutes, inside and outside the cell after 10, 20, 30 and 40 minutes in the solution.

(i) Using the information in the diagrams, describe the changes that have taken place in the concentrations of solute P and solute R, in the 40 minute period.
Suggest an explanation for these changes.
(5)
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(ii) Complete the diagram below, to show the concentration of solute P and solute R inside and outside the cell, after 50 minutes.
(1)

(Total for question = 9 marks)

Q2.
 
Mutations in genetic material such as DNA often result in the formation of new alleles.
The graph gives information about chloride transport in the human respiratory system with the normal allele for the CFTR protein and with the three mutated CFTR alleles.

The table gives information about the CFTR protein produced by cystic fibrosis (CF) sufferers with mutated alleles.

Assess the effect that these mutations have on the human respiratory system.
(6)
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(Total for question = 6 marks)

Q3.
 
DNA is a polymer made from monomers called nucleotides.
Different theories for DNA replication have been suggested. Figure 1 illustrates two of these theories.

Figure 1
Meselson and Stahl carried out experiments to test these theories for DNA replication.
Figure 2 shows the results from one of their experiments.

Figure 2
Analyse the data to explain why Meselson and Stahl accepted one of the models for DNA replication and rejected the other.
(4)
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(Total for question = 4 marks)

Q4.
 
Cells in the walls of the alveoli secrete a fluid.
This fluid, containing proteins and lipoproteins, acts as a surfactant.
The layer of surfactant, shown in the diagram, prevents the alveoli collapsing.

Alveolar cells undergoing protein synthesis were investigated.
Cells containing amino acids labelled with a fluorescent marker were monitored for 30 minutes.
The percentage of fluorescence inside and outside the cells was measured.
The results are shown in the table.

Explain how these labelled amino acids would be incorporated into a surfactant protein.
(4)
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(Total for question = 4 marks)

Q5.
 
Some fish live in very cold parts of the sea where ice can form.
Many of these fish produce anti-freeze proteins, which help to stop ice forming inside the fish.
Some fish produce another anti-freeze protein, called AFP II.
The tissues of these fish were tested for the presence of AFP II and the mRNA coding for AFP II.
The results are shown in the table.

Explain the distribution of the AFP II protein and AFP II mRNA.
(4)
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(Total for question = 4 marks)