Genes and inheritance
Chromosomes are made from DNA. Genes are short sections of DNA. Alleles are different forms of a gene. They can be dominant or recessive. Genetic diagrams help us to understand the possible outcomes when parents produce offspring. Cystic fibrosis is a disorder of the cell membranes caused by a recessive allele. Sickle cell disease is another example of a genetic disorder.
DNA [DNA: The material inside the nucleus of cells, carrying genetic information. DNA stands for Deoxyribonucleic Acid. ] (deoxyribose nucleic acid) molecules are large and complex. They carry the genetic code that determines the characteristics of a living thing.
Except for identical twins, each person’s DNA is unique. This is why people can be identified using DNA fingerprinting. DNA can be cut up and separated, forming a sort of 'bar code' that is different from one person to the next.
A genegene: The basic unit of genetic material inherited from our parents. A gene is a section of DNA which controls part of a cell's chemistry - particularly protein production. is a short section of DNA. Each gene codes for a specific protein by specifying the order in which amino acids must be joined together.
The cell’s nucleus contains chromosomeschromosomes: Rod shaped bodies found in the nucleus of cells that contain genetic information (DNA). made from long DNA molecules.
The diagram shows the relationship between the cell, its nucleus, chromosomes in the nucleus, and genes.