Question

section 4.2 sexual reproduction when somatic cells reproduce by mitosis, the new daughter cells have the same genetic information as the parent cells. reproduction that requires only one parent and leads to the production of genetically identical offspring is called asexual reproduction. bacteria are an example of an organism that reproduces by asexual reproduction. if mitosis were the only strategy for reproducing cells, we would produce exact clones of ourselves during reproduction. however, except for identical twins, no person is an exact genetic copy of another. that is because humans reproduce through sexual reproduction, which involves two parents and leads to the production of genetically distinct offspring. haploid and diploid cells in sexual reproduction sexual reproduction involves the fusion of a male reproductive cell with a female reproductive cell. these reproductive cells are called gametes, and the cell that results from this fusion is called a zygote. the process of combining gametes to form a zygote is called fertilization. in humans, the male gamete is the sperm cell and the female gamete is the egg cell or ovum. figure 4.12 shows that when gamete cells fuse during fertilization, the resulting zygote has the same number of chromosomes as the somatic cells for that organism. gametes must, therefore, have half the number of chromosomes as the parent cells. gametes, which contain single, unpaired chromosomes, are said to be haploid (from a greek word meaning single). the haploid number of chromosomes in a species is designated as n. cells that contain pairs of chromosomes, which includes all somatic cells, are said to be diploid (from a greek word meaning double). each human gamete is haploid, with n = 23. after fertilization, the zygote cell is diploid with a total of 2n chromosomes - that is, 23 chromosomes from the female parent plus n chromosomes from the male parent. the diploid number in humans, therefore, is 46. notice that n also describes the number of pairs of chromosomes in an organism. when two human gametes combine, 23 pairs of homologous chromosomes are formed. haploid and diploid cells in fertilization female (diploid) 2n male (diploid) 2n meiosis male gamete (haploid) n female gamete (haploid) n fertilization zygote (diploid) 2n grows into adult male or adult female figure 4.12 when gametes combine in fertilization, the resulting cell is diploid. describe in this example, how many chromosomes does the diploid cell have? key terms asexual reproduction sexual reproduction gamete zygote fertilization haploid diploid meiosis synapsis spermatogenesis oogenesis crossing over non - disjunction monosomy trisomy asexual reproduction reproduction that requires only one parent and produces genetically identical offspring sexual reproduction reproduction that requires two parents and produces genetically distinct offspring gamete a male or female reproductive cell zygote a cell formed by the fusion of two gametes fertilization in humans the joining of male and female haploid gametes haploid a cell that contains half the number of chromosomes as the parent cell diploid a cell that contains pairs of homologous chromosomes

Explanation:

Step1: Identify relevant information

In humans, each gamete is haploid with $n = 23$ chromosomes.

Step2: Recall diploid - gamete relationship

A diploid cell is formed by the fusion of two gametes. So the number of chromosomes in a diploid cell is $2n$.

Step3: Calculate number of chromosomes in diploid cell

Substitute $n = 23$ into $2n$. We get $2\times23=46$.

Answer:

46