An apple plant can produce sexually and asexually and it has 40 chromosomes in its leaf cells. How many chromosomes would be in each gamete and somatic cell?

Step 1: Analyze the question The leaf cell is a somatic (body) cell. It has 40 chromosomes, which is the diploid number (2n = 40). We need the chromosome number in gametes and in somatic cells.

Step 2: The concept

• Somatic cells (body cells such as leaf, root, and stem cells) are diploid (2n). They carry two sets of chromosomes, one from each parent.
• Gametes (sex cells) are haploid (n). They form by meiosis, which halves the chromosome number so that fertilisation restores the diploid number.
• Asexual reproduction uses mitosis, so the offspring keep the same number as the parent (2n).

Step 3: Solution

• Somatic cells: 2n = 40 chromosomes
• Gametes: n = 40 ÷ 2 = 20 chromosomes
• Check: fertilisation gives 20 + 20 = 40, so the diploid number is restored.

Step 4: Match the options

• A: Somatic cells with 10 is wrong, because they should have 40.
• B: This reverses the two numbers.
• C: 20 in gametes and 40 in somatic cells. This is correct.
• D: This says gametes have 40, so meiosis would not halve the number.

Correct answer: C

Tip: Remember "Gametes are Half, Somatic are Same as the parent." Whatever number the question gives for a body cell (leaf, skin, root) is 2n. Halve it for gametes. This works for any similar question, such as humans with 46 in body cells and 23 in gametes.