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Mice have a diploid number of 40 - VCE - SSCE Biology - Question 8 - 2013 - Paper 1
Question 8
Mice have a diploid number of 40. a. How many chromosomes are there in each of the following cells? sperm of a mouse fertilised egg of a mouse b. Briefly state... show full transcript
Worked Solution & Example Answer:Mice have a diploid number of 40 - VCE - SSCE Biology - Question 8 - 2013 - Paper 1
Step 1
a. How many chromosomes are there in the sperm of a mouse?
Answer
The sperm of a mouse is haploid, meaning it contains half the chromosome number of the diploid number. Since the diploid number is 40, the haploid number in the sperm will be:
Thus, the sperm of a mouse contains 20 chromosomes.
Step 2
a. How many chromosomes are there in the fertilised egg of a mouse?
Answer
The fertilised egg (or zygote) of a mouse is diploid as it contains chromosomes from both the sperm and the egg. Since the diploid number is given as 40, the fertilised egg will contain:
Therefore, the fertilised egg of a mouse has 40 chromosomes.
Step 3
b. Briefly state the biological significance of the process of meiosis.
Answer
Meiosis is crucial for sexual reproduction and has several significant biological roles:
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Genetic Variation: Meiosis leads to genetic diversity in offspring through processes such as independent assortment and crossing over. These processes shuffle the genetic material, resulting in gametes that have varied combinations of genes.
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Haploid Gametes: It ensures that the resulting gametes (sperms and eggs) are haploid, meaning they contain half the chromosome number of the parent organism. This is critical for maintaining the stable chromosome number across generations when fertilisation occurs.
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Evolutionary Advantage: By providing variation, meiosis enhances a species' ability to adapt to changing environments and survive under different selection pressures.