Organisation and Control of Eukaryotic Genome

Question 1

Describe the organisation of the eukaryotic genome.

Answer 1

1. Winding of -vely charged DNA around groups of 8 +ve charged core histone proteins –> nucleosome
   Linker DNA not wound around histones joins adjacent nucleosomes. Histone H1 poteins bind to the site where DNA enters and exits nucleosome –> stabilising nucleosome
2. Coiling of nucleosomes into a helical structure of 30nm chromatin with histone H1 proteins facing the centre
3. Structure form looped domains –> coil, fold, associate with central nuclear matrix scaffold proteins –> form condensed chromosome

Question 2

Describe the structure of the eukaryotic genome.

Answer 2

• Eukaryotes are much larger than prokaryotes
• Consist of 2 or more linear chromosomes which consists of a single linear
• Coding sequence interrupted by non coding introns
• Each gene has its own promoter
• All eukaryotes possess smaller, circular mitochondrial genomes
• 90% of euk genome do not code for protein or RNA