1 Sickle cell disease is a genetic disorder caused by recessive alleles - Edexcel - GCSE Biology - Question 1 - 2012 - Paper 1
Question 1
1 Sickle cell disease is a genetic disorder caused by recessive alleles.
a) (i) State the meaning of the word allele.
(ii) Human characteristics are coded for by g... show full transcript
Worked Solution & Example Answer:1 Sickle cell disease is a genetic disorder caused by recessive alleles - Edexcel - GCSE Biology - Question 1 - 2012 - Paper 1
Step 1
State the meaning of the word allele.
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Answer
An allele is a different form of the same gene. For example, it can have alternative forms such as 'A' or 'a'.
Step 2
Describe where genes are found inside a human cell.
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Answer
Genes are located on chromosomes, which are found within the nucleus of the cell. Specifically, genes are segments of DNA that code for specific traits.
Step 3
Complete the sentence by putting a cross (✓) in the box next to your answer.
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Answer
Sickle cell disease causes a change in the shape of the C red blood cells.
