Studyledge

The Mitotic Cell Cycle: Question 4

Syllabus 5.1

Multiple choice AS 1 mark

Skin cells at the edge of a healing wound divide repeatedly to replace the tissue that was lost.

Which statement correctly explains why mitosis, rather than meiosis, is the appropriate type of cell division for repairing this tissue?

Choose an answer to check it, then compare with the worked solution below.
Show worked solution Hide worked solution

Worked solution

Step 1: Recall what mitosis produces

Mitosis is nuclear division that produces two daughter cells with the same chromosome number as the parent cell (diploid, in most body cells) and genetically identical to it and to each other, because each daughter cell receives one full set of the sister chromatids formed by DNA replication in the preceding S phase. This contrasts with meiosis, which involves two divisions, includes crossing over and independent assortment as sources of genetic variation, and produces four haploid cells with half the chromosome number, each genetically different from the others.

Step 2: Apply this to tissue repair

Repairing a wound requires new skin cells that can function exactly like the cells they are replacing, so that the repaired tissue works normally as part of the organism. This means the new cells must have the same chromosome number as the surrounding tissue (diploid) and carry the same genetic information as the original cells. Mitosis meets both requirements: it produces genetically identical diploid daughter cells, so the replacement cells fit seamlessly into the existing tissue. Meiosis would be entirely unsuitable here, since it produces genetically varied, haploid cells intended for sexual reproduction, not for replacing diploid body cells.

Step 3: Evaluate each option

  • A: incorrect. This describes an outcome of meiosis (four haploid cells), not mitosis, and cells produced this way do not “fuse” to restore chromosome number.
  • B: incorrect. Halving the chromosome number is a feature of meiosis; mitosis keeps the chromosome number the same as the parent cell.
  • C: correct. Mitosis produces genetically identical diploid cells, exactly matching the requirement of replacing damaged skin cells with functionally identical ones.
  • D: incorrect. Crossing over and new allele combinations are features of meiosis (prophase I); mitosis does not introduce genetic variation between the daughter cells.

Final answer

  • Mitosis is appropriate for tissue repair because it produces genetically identical diploid daughter cells that can replace damaged cells exactly, option C.