Study the diagram given below which represents a stage during the mitotic cell division and answer the questions that follow: Study the diagram given below which represents a stage during the mitotic cell division and answer the questions that follow:
Which is the cell division that results in half the number of chromosomes in daughter cells?
Topic: Meiosis
Answer
MEIOSIS (reduction division).
MEIOSIS is called REDUCTION DIVISION because it HALVES the chromosome number — 46 to 23 in humans.
WHY IT MUST: gametes fuse at fertilisation. If each carried 46, the zygote would have 92 and the number would DOUBLE every generation. Halving it beforehand means fusion restores exactly 46.
THE CONTRAST to hold: MITOSIS — body cells, for GROWTH and REPAIR; number UNCHANGED; TWO daughter cells, genetically IDENTICAL MEIOSIS — gamete formation only; number HALVED; FOUR daughter cells, NOT identical
Meiosis also produces VARIATION, through crossing over and the independent assortment of chromosomes — which is why siblings differ from one another.