Question

How many chromosomes do human beings have?

Answer 1

Hint: Chromosomes are tightly coiled DNA strands present within the nucleus of almost all cells in our body. One set of chromosomes come from father and the other set comes from mother.

Complete answer:
There are 23 pairs of chromosomes, 46 in number, in a human body. Chromosomes are made of nucleoproteins which constitute the basic protein and nucleic acid.

Additional Information: -The chromosomal theory of inheritance was proposed by Sutton and Boveri in 1902.
-Two kinds of nucleic acid are recognized, which are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
-DNA and RNA are genetic material of the cell which make our chromosomes contain thousands of genes.
-A single length of DNA is wrapped several times around lots of protein molecules called histones, to form structures called nucleosomes.
-The nucleosomes coil up tightly to create chromatin loops. The chromatin loops are then wrapped around each other to make a full chromosome.
-In the case of chromosomal mutation, the number or position of the existing gene is altered.
-Two short arms (p arms), two longer arms (q arms), and a centromere at the center are present in each chromosome.
-The first 22 pairs of chromosomes are called autosomes (non-sex chromosomes) and look the same for both males and females.
-At the ends of each of the chromosomes are sections of DNA called telomeres.

Note: Among the 23 pairs of chromosomes, the 23rd pair are sex chromosomes(which determine whether the offspring will be male or female), XX for females, or XY for males. Hence, they participate in sex determination.