Transcription in prokaryotes and eukaryotes PDF

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Similarities and differences....

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Question: Write down the similarities and differences of transcription in prokaryotes and eukaryotes. Answer: Similarities of Transcription in Prokaryotes and Eukaryotes: There are several characteristics of transcription that are similar between prokaryotes and eukaryotes. 1. The core is very conserved between the species from E-Coli to Humans. 2. The active site is also quite conserved, both polymerase using magnesium ions to facilitate transcription, and a bridge helix to facilitate translocation of the enzyme. 3. The “Clamp” and “Rudder” regions are structurally conserved between prokaryotes and eukaryotes. 4. Abortive transcripts are also found in both prokaryotes and eukaryotes. 5. The respective polymerases also bind to promoters, and have upstream elements that can enhance transcription. 6. For instance both go through an initiation, elongation, and termination phase. 7. Chemical composition of transcript is same in both groups. 8. In both, one strand of the DNA duplex is act as a template. 9. Transcription is facilitated by the enzyme RNA polymerase in both prokaryotes and eukaryotes. 10. Protein synthesis occurs in the cytoplasm in both prokaryotes and eukaryotes.

Difference of Transcription in Prokaryotes and Eukaryotes: Prokaryotes 1. Prokaryotes are single-celled organisms that do not have a nucleus or any membrane bound organelle. 2. Prokaryotic cells are much smaller than eukaryotic cells, so they do not need organelles because they do not have as many components. 3. Prokaryotes do not have an Endoplasmic Reticulum, a Golgi apparatus, Lysosomes, or Peroxisomes. 4. Prokaryotes have only one RNA polymerase. 5. Prokaryotes have six subunits in their

Eukaryotes 1. Eukaryotes are single-celled or multicelled organisms that have a nucleus and membrane bound organelle. 2. Eukaryotic cells are much larger, more complex and have more components. 3. Eukaryotes do have an Endoplasmic Reticulum, a Golgi apparatus, Lysosome, and Peroximoses. 4. Eukaryotes have three polymerase RNA polymerases I, II, III. 5. Eukaryotes polymerase II have twelve subunits and seven transcription factors.

main polymerase. 6. The prokaryotic active site has an always bent bridge helix. 7. Prokaryotes binds to two promoters, one at the 10-position and one at the 35-position. 8. Transcription initiation machinery is simple since DNA is not associated with histone protein. 9. Genes usually polycistronic and hence single transcript may contain sequence for many polypeptides. 10. SD sequence present about 8 nucleotide upstream of start codon in the mRNA, SD sequence act as the ribosome binding site.

6. The eukaryotic active site has a straight bridge helix that bend to facilitate translocation. 7. Eukaryotes binds at the 25- position, also known as TATA box. 8. Transcription initiation machinery is very complex since the genetic material is associated with protein. 9. Genes are monocistronic thus single transcript code for only one polypeptide. 10. SD sequence is absent in it....