NEET BIOLOGY

GENETICS AND EVOLUTION

GENETIC BASIS OF INHERITANCE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What happens to the chromosome number after meiosis and after mitosis?
A
meiosis-halved; mitosis-halved
B
meiosis-halved; mitosis-stays the same
C
meiosis-stays the same; mitosis-halved
D
meiosis-stays the same; mitosis-stays the same
Explanation: 

Detailed explanation-1: -Mitosis creates two identical daughter cells that each contain the same number of chromosomes as their parent cell. In contrast, meiosis gives rise to four unique daughter cells, each of which has half the number of chromosomes as the parent cell.

Detailed explanation-2: -At the end of mitosis, the two daughter cells will be exact copies of the original cell. Each daughter cell will have 30 chromosomes. At the end of meiosis II, each cell (i.e., gamete) would have half the original number of chromosomes, that is, 15 chromosomes.

Detailed explanation-3: -Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for sexual reproduction.

Detailed explanation-4: -So during a mitotic cell cycle, the DNA content per chromosome doubles during S phase (each chromosome starts as one chromatid, then becomes a pair of identical sister chromatids during S phase), but the chromosome number stays the same.

Detailed explanation-5: -The other type of cell division, meiosis, ensures that humans have the same number of chromosomes in each generation. It is a two-step process that reduces the chromosome number by half-from 46 to 23-to form sperm and egg cells.

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