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Genome

Biology: AQA GCSE Higher, topic 6.1.7

The Genome

The genome is the entire (all) genetic material of an organism. Within a genome, there are lots of levels of organisation:

DNA

DNA

  • DNA is a double helix polymer, which means it is a polymer (a large molecule made up of many subunits) made up of two strands forming a twisted, ladder shape.
Genes

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

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.

Test yourself on Genome

  • What is the relationship between a chromosome and the genes it contains?

  • What is the relationship between DNA and a chromosome?

  • Why is DNA classed as a polymer?

  • What is the relationship between an organism's genome and its chromosomes?

  • Why does a human body cell contain 23 pairs of chromosomes rather than 23 single chromosomes?

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