Sperm cells and egg cells are formed by meiosis - AQA - GCSE Biology - Question 3 - 2020 - Paper 1
Question 3
Sperm cells and egg cells are formed by meiosis.
1. During meiosis a cell divides twice.
How many sperm cells are formed when a cell divides by meiosis?
2. Human b... show full transcript
Worked Solution & Example Answer:Sperm cells and egg cells are formed by meiosis - AQA - GCSE Biology - Question 3 - 2020 - Paper 1
Step 1
During meiosis a cell divides twice. How many sperm cells are formed when a cell divides by meiosis?
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Answer
During meiosis, one diploid cell divides twice to produce four haploid sperm cells. Therefore, when a single cell divides by meiosis, it produces four sperm cells.
Step 2
Human body cells contain 46 chromosomes. How many chromosomes are in each human egg cell?
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Answer
Human body cells are diploid, containing 46 chromosomes. In contrast, human egg cells are haploid, carrying half this number. Hence, each human egg cell contains 23 chromosomes.
Step 3
A genetic disorder develops as a result of a change in a gene. What scientific term describes a change in a gene?
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Answer
The scientific term that describes a change in a gene is a 'mutation'.
Step 4
People with a family history of some genetic disorders are offered embryo screening. Suggest one way embryo screening can help people with a family history of a genetic disorder.
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Answer
Embryo screening can help by allowing prospective parents to identify embryos that are free from genetic disorders, thereby reducing the risk of passing on hereditary conditions.
