Chromosomes Structure Chromatids and chromatin Pdf
Genes, whether they are prokaryotic or eukaryotic, have the same structural features such as coding regions, promoter elements, and terminal sequences.
• However, detailed organizations vary in terms of sequence blocks and their positions. The major difference from prokaryotes is that the coding region is split into coding and noncoding regions.
Promoter regions and the ends of genes show different structural features, because eukaryotic genes, depending upon the kind of gene,they are transcribed by three different enzymes, whereas in prokaryotic systems all types of genes are transcribed by only one type of RNA polymerase, of course with different sigma factors for different set of genes.
• It clearly means eukaryotic gene structure, especially promoter regions, including their regulatory regions and their structure are different and more complicated.
So far except for a few simple genes, understanding of others is nebulous; this is in spite of great strides made in gene cloning, sequencing, and expressions of genes in different cell types.
• Genes transcribed by different enzymes have different