EVERYDAY SCIENCE

Detailed explanation-1: -Explanation: When compared to gametes of the same species, the amount of DNA and chromosome number of a somatic cell that had just completed the S-phase of its cell cycle contains 4 times more DNA and double the number of chromosomal. A gamete is a haploid in general. A diploid cell is a somatic cell.

Detailed explanation-2: -Final answer: A somatic cell that has just completed the S phase of its cell cycle, as compared to a gamete of the same species, has twice the number of chromosomes and four times the amount of DNA.

Detailed explanation-3: -During S phase, which follows G1 phase, all of the chromosomes are replicated. Following replication, each chromosome now consists of two sister chromatids (see figure below). Thus, the amount of DNA in the cell has effectively doubled, even though the ploidy, or chromosome count, of the cell remains at 2n.

Detailed explanation-4: -Somatic cells each have 46 chromosomes in total, with 23 chromosomes from each parent. Each somatic cell contains 23 homologous pairs and is considered diploid.

Detailed explanation-5: -At the end of S phase, cells are able to sense whether their DNA has been successfully copied, using a complicated set of checkpoint controls that are still not fully understood. For the most part, only cells that have successfully copied their DNA will proceed into mitosis.