Question

what are the similarties and differences between bacterial, archael, and eukaryotic transcription ( using RNa pol II) initiation.

Answer 1

First we talk ablout similarties:

1. Throughout biology,the RNA - synthesizing cores of multisubunit polymerases are similar in function,structure and sequence .
2. All multisubunit polymers require a specificity factor that recognizes specific core promoter elements and sets the start site for transcription. In bacteria, these factors are the subunits. In eukaryotes,pol II require TBP, which is part of the basal transcription factor TFIID, and another basal transcriotion factor, TFIIB.
3. The core promoter elements, recognized by the specificity factors,comprise building blocks that can be used in different combination at different promotors; deviation from consensus sequences allow additional regulation by other factors.
4. Across all domain of life , the ability to change core promoter specificity of RNA polymerase provide a major mechanism for regulating gene expression,particularly for developmental control.
5. Bacteria, archaea and eukaryotes share strategies to alter core prometer specificity, including swapping out specificity factors and auxiliary transcription activators that bind close to or overlap core promoter sequences to modify the RNAP- DNA interaction.

Differences:

Bacteria Archea Eukarya

1. polymers II type promoter absent Present present
2. post transcriptional modification of RNA ansent absent present
3. RNA polymers enzyme type one type several type three type (RNA pol I,II,III)
4. structure of RNA plymerase simple ,4 subunits complex,8-12 subunits    complex 12 -14 subunits
5. Rifampicin sesitivity of RNA polymers sensitive insensitive    insensitive
6. Nitrogen fixation present presnt    absent
7. growth at temperature above 80 *c some can grow most of them can grow none of them can grow