Biology- Genetic Info, variation and relationship between organisms

  • Created by: DonaJ2002
  • Created on: 21-01-19 14:35

Biology- Genetic Info, variation and relationship between organisms

In prokaryotic cells, DNA molecules are short, circular and not wound around histone proteins- instead it condenses to fit in cell by supercoiling. (Look in page 88 for diagram).

In the nucleus of eukartyotic cells, DNA molecules exists as chromosomes which are thread like, very long, linear and wound up around histone proteins, so that it can fit in the nucleus. Histone proteins support the DNA. Together, DNA molecule and associated histone protein coils tightly to form compact chromosomes. The mitochondira and chloroplasts in eukaryotic cells also have their own DNA and is similar to prokaryotic DNA because it's shorter and circular than DNA in the nucleus and isn't associated with histone proteins but instead it condenses to fit in the cell by supercoiling.

DNA contains genes- a gene is a base sequence of DNA bases that codes for:

1) Amino acid sequence for a polypeptide: Sequence of amino acids in a polypeptide forms primary structure of a protein and different polypeptides have different number and


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