Genome
Biology: Edexcel IGCSE, topic 4.2.3
The Genome
The genome is all the genetic material of an organism, inherited (passed down) from parents to offspring. Within a genome, there are lots of levels of organisation:
DNA
- DNA is double helix polymer, which means it is a polymer (a large molecule made up of many subunits called nucleotides) made up of two strands forming a twisted, ladder shape.
Genes
- A gene is a small section of DNA. Genes code for a sequence of amino acids, which combine to give a specific protein.
Chromosomes
- Long strands of DNA are coiled up to form chromosomes.
- Chromosomes contain many genes.
- Human body cells contain 23 pairs of chromosomes, one of each pair coming from each parent.