Why is it important that cells have half the number of chromosomes as body cells?

Answer 1

In sexual reproduction, each parent contributes a sex cell with half as many chromosomes as the normal cells. The two sex cells combine and the zygote will have the proper total of chromosomes. In this way, the offspring inherit genetic information from both parents.

Answer 2

This happens so the genetic material from both parents combines to make new set.

Answer 3

Sex cells must have half the number of chromosomes because when the the sperm fertilizes the egg, the total number of chromosomes in the offspring must be the same number as the parents.

Diploid and Haploid Cells

Body cells (or somatic cells as they are called in Biology) have diploid, or 2n number of chromosomes. Male and female sex cells have haploid, or n number of chromosomes. During the process of fertilization where the sperm (containing n number of chromosomes) fertilizes the ovum (also containing n number of chromosomes), they collectively reconstitute the diploid number thus creating a fertilized cell containing 2n number of chromosomes (n from ovum and n from sperm) This fertilized egg now containing the entire chromosomal constitution of the species (2n) goes on to develop into an embryo.

While in interphase, human cells are carrying out their normal functions and have 46 chromosomes, though the DNA does not exist as chromosomes at this point. For humans, 46 is known as the haploid number. Once a cell is ready to divide, the DNA (called chromatin) condenses into chromatids. The chromatids duplicate, forming the familiar X shapes, called chromosomes. At this point, one human cell contains enough genetic material for 92 chromosomes, double the normal amount. This is the diploid number. In mitosis, the cell divides in two, and each new cell each has 46 chromosomes worth of genetic material, the normal amount.

In meiosis, which produces sex cells, the resulting cells must each have 23 chromosomes because in sexual reproduction, 23 chromosomes from father + 23 chromosomes from mother = 46 chromosomes in the offspring. In meiosis, the number of chromosomes doubles, creating the diploid amount. The cell divides, so 2 cells with 46 chromosomes are produced. These cells then divide without duplicated DNA, so 4 cells with 23 chromosomes are produced. Keep in mind that the number of chromosomes is not related to the complexity of the organism. Humans have 46 chromosomes, ferns have over 1,000.

Answer 4

Body cells (or somatic cells as they are called in biology) have diploid, or 2n number of chromosomes.

Male and female sex cells have haploid, or n number of chromosomes. During the process of fertilization where the sperm (containing n number of chromosomes) fertilizes the ovum (also containing n number of chromosomes), they collectively reconstitute the diploid number thus creating a fertilized cell containing 2n number of chromosomes (n from ovum and n from sperm)

This fertilized egg now containing the entire chromosomal constitution of the species (2n) goes on to develop into an embryo

Answer 5

While in interphase, human cells are carrying out their normal functions and have 46 chromosomes, though the DNA does not exist as chromosomes at this point. For humans, 46 is known as the haploid number. Once a cell is ready to divide, the DNA (called chromatin) condenses into chromatids. The chromatids duplicate, forming the familiar X shapes, called chromosomes. At this point, one human cell contains enough genetic material for 92 chromosomes, double the normal amount. This is the diploid number. In mitosis, the cell divides in two, and each new cell each has 46 chromosomes worth of genetic material, the normal amount. In meiosis, which produces sex cells, the resulting cells must each have 23 chromosomes because in sexual reproduction, 23 chromosomes from father + 23 chromosomes from mother = 46 chromosomes in the offspring. In meiosis, the number of chromosomes doubles, creating the diploid amount. The cell divides, so 2 cells with 46 chromosomes are produced. These cells then divide without duplicated their DNA, so 4 cells with 23 chromosomes are produced. Keep in mind that the number of chromosomes is not related to the complexity of the organism. Humans have 46 chromosomes, ferns have over 1,000.