Monday, November 3, 2008

Q: compare and contrast the prokaryotic and eukaryotic genomes

The eukaryotic genome is diploid but the prokaryotic genome is haploid. The eukaryotic genome has multiple origins of replication but the prokaryotic genome has only one origin of replication. The eukaryotic genome may have more than one chromosome but the prokaryotic genome has only one chromosome. The chromosomes in eukaryotic cells are linear but the chromosome in prokaryotic cells is circular. The eukaryotic genome size is much larger (10 to 100000 million bases) but the prokaryotic genome size is much smaller (0.6 to 10 Mb). The eukaryotic gene length is around one an a half times as long as the prokaryotic gene length. The eukaryotic genome is much more complex, with distinct regions such as the centromere and the telomere, whereas the prokaryotic genome is much simpler with no distinct regions. In the eukaryotic genome, the DNA is bound to histone proteins to form nucleosomes, which wind around each other to form chromosomes, but in the prokaryotic genome, DNA is bound to nucleoid associated proteins to form a DNA-protein complex. The eukaryotic genome is enclosed within a true membrane bound nucleus but the prokaryotic genome does not have a true nucleus, only a region called the nucleoid.

No comments: