NEET BIOLOGY

CELL STRUCTURES AND FUNCTION

CELL DIVISION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A sperm fertilizes an egg in the fallopian tube of the female reproductive system, each containing 23 chromosomes. How many chromosomes are in the resulting zygote?
A
23
B
46
C
12
D
92
Explanation: 

Detailed explanation-1: -The male gamete, a sperm, and the female gamete, an ovum, are both haploid and contain 23 chromosomes. [2] As the end result of gamete fusion, a zygote is diploid with 23 pairs of chromosomes (46 chromosomes). Fertilization usually occurs in the ampullary part of the fallopian (uterine) tube.

Detailed explanation-2: -The number of chromosomes in a human sperm is half the number of chromosomes in a zygote, i.e., their ratio is 2 : 1.

Detailed explanation-3: -The ratio is 1:2 of chromosome number between an egg and its zygote. Sperms contain either X or Y chromosome whereas an egg will always have an X chromosome.

Detailed explanation-4: -Through the process of fertilization, egg and sperm join to make a cell with 46 chromosomes (23 pairs), called a zygote. For each chromosome pair, one homologous chromosome came from each parent. They have the same genes arranged in the same order, but there are small variations in the DNA letters of those genes.

Detailed explanation-5: -A zygote, also known as a fertilized ovum or fertilized egg, is the union of a sperm cell and an egg cell. The zygote begins as a single cell but divides rapidly in the days following fertilization. The zygote’s single cell contains all of the 46 necessary chromosomes, getting 23 from the sperm and 23 from the egg.

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