Question 18 of 19intermediate💡 UnderstandShort Answer2 marks

What would happen if gametes are formed by mitotic divisions?

Correct Answer

If gametes are formed by mitotic divisions, they will have the same number of chromosomes and DNA as the parent cell instead of half. Mitosis produces two genetically identical daughter cells, meaning the chromosome number is not reduced.

During fertilisation, when these gametes combine, the original chromosome number would not be restored; instead, it would double, leading to an abnormal number of chromosomes in the offspring. Furthermore, since mitosis produces identical cells, the gametes would not create variations and diversity among living organisms, which is normally achieved through meiosis.

Exercise: Revise, Reflect, Refine | Q: 15
For More Understanding

Explanation

The textbook context states that mitosis produces genetically identical daughter cells with the same DNA and same number of chromosomes as the parent cell, whereas meiosis reduces the chromosome number to half in gametes. If gametes were formed by mitosis, they would retain the full set of chromosomes. Upon fertilisation, combining two full sets would double the chromosome number instead of restoring the original number, leading to an abnormal chromosome count. Additionally, the context highlights that meiosis creates variations and diversity, a feature that would be lost if gametes were formed identically through mitosis.

Solution Steps

  1. Step 1: Identify the effect of mitosis on chromosome number (it remains the same as the parent cell, not halved).

  2. Step 2: Determine the consequence during fertilisation (chromosome number would double instead of being restored, causing an abnormal number of chromosomes).

  3. Step 3: Note the loss of genetic variation, as mitosis produces identical cells rather than creating the variations and diversity typical of meiosis.

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