Paper 2 H - SAMPLE SET 1 Q7 Answers
7) Figure 8 shows an image of a small section of DNA.
Figure 9 shows the structure of a small section of DNA.
Figure 9 shows the structure of a small section of DNA.
7.1) What is Part B? [1 mark]
7.2) In Figure 8 the structure of DNA shows four different bases.
There are four different bases and they always pair up in the same pairs.
Which bases pair up together? [1 mark]
Syndrome H is an inherited condition.
People with syndrome H do not produce the enzyme IDUA.
Figure 9 shows part of the gene coding for the enzyme IDUA.
7.2) In Figure 8 the structure of DNA shows four different bases.
There are four different bases and they always pair up in the same pairs.
Which bases pair up together? [1 mark]
Syndrome H is an inherited condition.
People with syndrome H do not produce the enzyme IDUA.
Figure 9 shows part of the gene coding for the enzyme IDUA.
Strand K shows a mutation in the DNA which has caused syndrome H.
7.3) The enzyme IDUA helps to break down a carbohydrate in the human body.
The enzyme IDUA produced from Strand K will not work.
Explain how the mutation could cause the enzyme not to work. [5 marks]
7.4) A recessive allele causes syndrome H.
A heterozygous woman and a homozygous recessive man want to have a child.
Draw a Punnett square diagram to determine the probability of the child having syndrome H.
Identify any children with syndrome H. [5 marks]
Use the following symbols:
A = dominant allele
a = recessive allele
7.3) The enzyme IDUA helps to break down a carbohydrate in the human body.
The enzyme IDUA produced from Strand K will not work.
Explain how the mutation could cause the enzyme not to work. [5 marks]
7.4) A recessive allele causes syndrome H.
A heterozygous woman and a homozygous recessive man want to have a child.
Draw a Punnett square diagram to determine the probability of the child having syndrome H.
Identify any children with syndrome H. [5 marks]
Use the following symbols:
A = dominant allele
a = recessive allele
Probability = _____________
(Total for Question 7 = 12 marks)