GENETICS

Transcription is the process of synthesizing ribonucleic acid (RNA). Synthesis takes place within the nucleus of eukaryotic cells or in the cytoplasm of prokaryotes and converts the genetic code from a gene in deoxyribonucleic acid (DNA) to a strand of RNA then directs protein synthesis.

In classical Mendelian genetics, each character is governed by a pair of character called as allele. One allele comes from father and second allele comes from mother. In a diploid organism, each gene has two alleles. Phenotype is a term that describes external characters of an organisms that are visible to naked eye. Genotype refers to the genetic constitution of an organism.

A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases. An international research effort called the Human Genome Project, which worked to determine the sequence of the human genome and identify the genes that it contains, estimated that humans have between 20,000 and 25,000 genes.