LIFE SCIENCE

Detailed explanation-1: -In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females.

Detailed explanation-2: -A picture of all 46 chromosomes in their pairs is called a karyotype. A normal female karyotype is written 46, XX, and a normal male karyotype is written 46, XY.

Detailed explanation-3: -Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 13, one copy inherited from each parent, form one of the pairs. Chromosome 13 is made up of about 115 million DNA building blocks (base pairs) and represents between 3.5 and 4 percent of the total DNA in cells.

Detailed explanation-4: -In meiosis, a cell containing the diploid number of chromosomes is converted into four cells, each having the haploid number of chromosomes. In human cells undergoing meiosis, for instance, a cell containing 46 chromosomes yields four cells, each with 23 chromosomes.