Question

A cow has 60 chromosomes in one of its somatic cells. How many chromosomes would each of the cells of a new cow embryo have?

Answer 1

Hint: Cell division is an important biological process that results in the formation of daughter cells giving rise to the next generation. Cell division is highly regulated and comprises cytoplasmic division and nuclear division.

Complete answer:
Nuclear division is of two kinds- mitosis and meiosis. Mitosis is the process during which a replicated chromosome gets equally segregated into two daughter cells. Mitosis comprises the following stages-prophase, prometaphase, metaphase, anaphase and telophase. During prophase the cell prepares to undergo division by condensing its chromosome and inducing mitotic spindle formation. During prometaphase microtubules start to assemble that are later used to separate the chromosome into chromatids. During metaphase the chromosomes are arranged on the equatorial plane which is located centrally between two centrosomes.

During anaphase due to shortening of the spindle fibers the chromosomes get pulled to chromatids. During telophase a new nuclear envelope forms and the chromosomes begin to decondense. Meiosis takes place in sexually reproducing organisms giving rise to gametes. Meiosis comprises meiosis I and meiosis II phases. Somatic cells undergo mitotic cell division, so a cow which has 60 chromosomes in its somatic cell after mitosis each daughter cell will receive 30 chromosomes. But two daughter cells come together to form cells of the embryo so the embryo will also comprise 60 chromosomes.

Note: Both mitosis and meiosis are important biological processes and are thus tightly regulated. Mitosis not only helps in growth and development but also helps in replacement of damaged cells and regeneration of body parts.