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4 (a) Figure 5 shows how alcohol consumption increases the risk of developing liver cancer - Edexcel - GCSE Biology Combined Science - Question 4 - 2021 - Paper 1
Question 4
4 (a) Figure 5 shows how alcohol consumption increases the risk of developing liver cancer. Someone who does not drink alcohol has a 1.0 risk of developing liver can... show full transcript
Worked Solution & Example Answer:4 (a) Figure 5 shows how alcohol consumption increases the risk of developing liver cancer - Edexcel - GCSE Biology Combined Science - Question 4 - 2021 - Paper 1
Step 1
Calculate the risk of developing liver cancer for someone who consumes 4 units of alcohol a day.
Answer
To determine the risk of developing liver cancer for someone who consumes 4 units of alcohol:
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Convert units of alcohol to grams:
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Based on the graph in Figure 5, since a consumption of 32 grams corresponds to a risk factor of 1.2, the risk of developing liver cancer is:
Step 2
Describe how cancer develops in the liver.
Answer
Cancer development in the liver involves several key processes:
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Mutations in DNA: Changes or mutations occur in the DNA sequence of liver cells.
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Uncontrolled cell division: These mutations lead to rapid and uncontrolled cell division.
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Formation of tumors: The uncontrolled division results in the formation of a tumor, which is a mass of abnormal cells.
Step 3
Step 4
State and explain the genotype of female Z.
Answer
The genotype of female Z is heterozygous. This means that she has one dominant allele and one recessive allele for the haemochromatosis trait.
- Explanation: One offspring must have inherited the recessive allele for haemochromatosis, indicating that at least one parent is a carrier. Therefore, female Z cannot be homozygous recessive.