Two kinds of molecules participate in protein synthesis. Both are based on a similar building block, the nucleotide, giving them their name—nucleic acids. One of these molecules, deoxyribonucleic acid or DNA, is the genetic material, and the other, ribonucleic acid or RNA, is produced in the nucleus and moves to the cytoplasm, where it participates [...]
Mutations are changes in the DNA sequence of a cell’s genome and are caused by radiation, viruses, transposons and mutagenic chemicals, as well as errors that occur during meiosis or DNA replication. They can also be induced by the organism itself, by cellular processes such as hypermutation. Mutation can result in several different types of [...]
In the early 1900s, attention turned to the cell to find a chromosomal explanation for the determination of maleness or femaleness. Some of the evidence for a chromosomal basis for sex determination came from work with the insect Protenor. One darkly staining chromosome of Protenor, called the X chromosome, is represented differently in males and [...]
DNA is the genetic material, and it exists with protein in the form of chromosomes in eukaryotic cells. During most of the life of a cell, chromosomes are in a highly dispersed state called chromatin. During these times, units of inheritance called genes (Gr. genos, race) may actively participate in the formation of protein. When [...]
1. The genetic material is organized into chromosomes. Chromosomes may be represented differently in males and females. However, the number of chromosomes is constant for a given species. 2. Mitosis is the form of cell division that results in growth and repair processes. It ensures an orderly and accurate distribution of chromosomes during the cell [...]
