Question: 100% NCERT covered from Particular Keyword.Explanations are 100% from NCERT | [Difficult level: Easy] From NCERT NEET Derived Question.
Significance of meiosis lies in
(a) reduction of chromosome number to one half.
(b) maintaining consistancy of chromosome number
during sexual reproduction.
(c) production of genetic variability.
(d) all of the above.
Answer:
(d) Meiosis results in four daughter cells and each with
having half the number of chromosomes of the parent
cell. Meiosis begins with a parent cell that is diploid,
i.e it has two copies of each chromosome. The parent
cell undergoes one round of DNA replication
followed by two separate cycles of nuclear division.
The process leads to production of four daughter
cells that are haploid, which means that they contain
half the number of chromosomes of the diploid parent
cell. The significance of meiosis are:
(i) It maintains the same chromosome number in the
sexually reproducing organisms. From a diploid cell,
haploid gametes are produced which in turn fuse to
form a diploid cell.
(ii) It restricts the multiplication of chromosome number
and maintains the stability of the species.
(iii) Maternal and paternal genes get exchanged during
crossing over which results in variations among the
offspring.
(iv) All the four chromatids of a homologous pair of
chromosomes segregate and go over separately to
four different daughter cells. This leads to variation
in the daughter cells genetically.
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