NEET BIOLOGY

CELL STRUCTURES AND FUNCTION

CELL DIVISION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
After fertilization, the zygote contains 28 chromosomes. What is the haploid number?
A
28
B
14
C
56
D
46
Explanation: 

Detailed explanation-1: -The haploid gametes fuse to form diploid zygote that is, the fertilization restored the diploid chromosomal number. Now, the number of chromosomes in the zygote is 28. Thus, the number of chromosomes in gametes must be half of 28 that is, 14.

Detailed explanation-2: -The number of chromosomes in the gamete is haploid and human gametes contain 23 chromosomes. As zygote is from the fusion of two gametes, the chromosome number is diploid and is double of that in gamete and thus has 46 chromosomes.

Detailed explanation-3: -The haploid number in humans is given as 2n=46, n = 23, this is because the haploid human cells possess one set of 23 chromosomes – 22 sets of autosomal chromosomes (non-sex chromosomes) and 1 set of sex chromosomes.

Detailed explanation-4: -Telophase II: During telophase II, cell division begins again in each of the two daughter cells, creating 4 daughter cells. Each of these 4 daughter cells contains 23 chromosomes, making them haploid, and none of the 4 is exactly alike (due to crossing over and independent assortment).

Detailed explanation-5: -2n = 16, n is the haploid number of chromosomes. 2n = 16, it means n = 8. The haploid number of chromosomes is 8.

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