Introduction

Before discussing the steps a cell must undertake to replicate and divide its DNA, a deeper understanding of the structure and function of a cell’s genetic information is necessary. A cell’s DNA, packaged as a double-stranded DNA molecule, is called its genome. In eukaryotes the genetic material is packaged the nucleus. In prokaryotes, the genome is composed of a single, double-stranded DNA molecule in the form of a loop or circle located in the cell’s cytoplasm.

The following video explains what is genomic DNA and the human genome?

Summary

• The principle that “every cell comes from another cell” is demonstrated in the cellular life cycle of any living organism.
• In prokaryotes, the genome is composed of a single, double-stranded DNA molecule in the form of a loop or circle called a nucleoid.
• In eukaryotes, humans for example, here are two types of cells; sex cells (the egg and the sperm) and somatic cells (everything else).
• Somatic cells divide by mitosis and sex cells divide by meiosis.
• The natural result of mitosis is the production of two genetically identical (somatic) cells.
• Mitosis is important for growth, development, replacement, and repair of most of the cells in our bodies.
• Meiosis is the process of gamete (sperm and egg) formation in which reproductive cells divide to yield four genetically different haploid cells (half the normal amount of genetic material).
• This process is important in providing genetic diversity and the proper amount of genetic material in offspring.
• When an egg fuses with a sperm, a zygote is created.
• This single cell then begins to divide by mitosis to create an embryo. The embryo continues to develop and once born will continue to develop until reproductive age when the organism’s life cycle can start again.

Sources:

“An Introduction to the Human Genome.” Uploaded by Harvard Univ., May 19, 2017, Retrieved from: https://youtu.be/jEJp7B6u_dY Licensed under: Standard YouTube License