A gene, made up of DNA (deoxyribonucleic acid), is a unit of heredity in a living organism. A gene is the basic physical and functional unit of heredity. Each cell we have as part of our physical being contains the complete copy of our individual genetic plan. This genetic plan is in our cells as genes.
Genes contain information. This information is for constructing and maintaining a living organism’s cells. Genes also hold the information necessary for passing genetic traits to offspring. The great majority of living organisms have their gene encoding in long strands of DNA.
Each individual has chromosomes (consisting of DNA) passed to them from their parent's. These chromosomes are essentially long strings of genes. The chromosomes come in pairs, one set from the father and one set from the mother. Thousands of genes make up each chromosome.
Each parent passes down 23 chromosomes to their offspring. Therefore, an individual has 46 chromosomes. The chromosomes in the nucleus of the cell come in pairs. Therefore, the genes in the nucleus also come in pairs.
Mitochondria also contain genes. Mitochondria are very small compartments that reside in the cytoplasm. The cytoplasm is outside the cell's nucleus. These mitochondria are the cell's energy centers.
A gene is a small part of cell DNA (deoxyribonucleic acid) and gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA The genes present in long strands of DNA (deoxyribonucleic acid) called chromosomes. Human being have 23 pair of chromosomes. The total number of chromosome is 46. In our body approximately 25000 genes are present. Every person has two copies of each gene, one inherited from each parent e.g. one from mother and one form father. Most genes are the same in all people, but a small number of genes (less than 1 percent of the total) are slightly different between people.