To extend elongation into the transcription unit, a kinase complex called P-TEFb is required. P-TEFb contains the CDK9 kinase, which is a member of the kinase family that controls the cell cycle. P-TEFb acts on the CTD to phosphorylate it further on serine 2 of the heptapeptide repeat.

TLS Online TPP Program

#Id: 7251

#Unit 5. Developmental Biology

T-independent response

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#Id: 470

#Unit 2. Cellular Organization

Intron do not face selective pressure to produce a polypeptide with a useful sequence hence highly variable.

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#Id: 6775

#Unit 3. Fundamental Processes

mRNP export from the nucleus into the cytoplasm is controlled by the phosphorylation and dephosphorylation of mRNP adapter proteins, REF, the NXF1/NXT1 mRNP exporter to mRNPs. 

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#Id: 2992

#Unit 3. Fundamental Processes

DNA polymerase I has a unique 5 '-3' exonuclease activity that can be combined with DNA synthesis to perform nick translation.

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#Id: 10150

#Unit 6. System Physiology – Plant

Strigolactones, which occur in about 80% of plant species, are a group of terpenoid lactones