In the bacterial lac repressor, which of these occurs: In the presence of glucos

Question

In the bacterial lac repressor, which of these occurs: In the presence of glucose and the absence of lactose, the repressor is actively produced. The lac operon can be hyper-induced in the presence of low glucose by the 'cAMP binding protein' (CAMP). In the presence of lactose and the absence of glucose the lac operon is repressed. Allolactose is a byproduct of beta-galactosidase, indicating high lactose when it builds up. In eukaryotes the enhancer elements can be quite a distance upstream or downstream from the promoter, and transcriptional regulation is helped by protein:protein interactions. The prokaryotic promoter contains a TATA box that is at -10bp upstream from the transcriptional start site. During the addition of the poly A tail which of these occurs: The transcript is synthesized beyond the poly A site (AAUAAA). The mRNA contains a 5' cap. The transcript is cleaved 35nt downstream from the poly A site. An enzyme complex containing an exonuclease and polyadenylate polymerase cleaves nearby the AAUAA site 100-300 A's are added to the 5' end.

Explanation / Answer

In the bacterial repressor which of these occur

In the presences of glucose and in the absence of lactose the repressor is actively produced

In the eukaryotes the enhancer elements can be quite a distance upstream or downstream from the promoter and transcriptional regulation is helped by protein : protein interaction

It is True.

In the eukaryotes the enhancer elements can be quite a distance upstream or downstream from the promoter and transcriptional regulation is helped by protein : protein interaction that in turn assist in the binding of RNA polymerase II to its promoter, When a DNA-bending protein binds, the shape of the DNA changes. This shape change allows for the interaction of the activators bound to the enhancers with the transcription factors bound to the promoter region and the RNA polymerase.

In the prokaryotic promoter contain a TATA box that is at -10bp upstream from the transcriptional start site

It is false

In the prokaryotic promoter, contain a Pribnow box, which is located at short sequence -10. Pribnow box is essential to start transcription in prokaryotes.

During the addition of the poly A tail

The transcript is cleaved 35nt downstream from the poly A tail

A complex consisting of several proteins forms on the 3 UTR of the pre-mRNA molecule. Cleavage and polyadenylation specificity factor (CPSF) bind to the AAUAAA consensus sequence, which is located upstream of the 3 cleavage site. Another protein, cleavage stimulation factor (CsTF), binds downstream of the cleavage site. Two cleavage factors and polyadenylate polymerase (PAP) also become part of the complex. Once the complex has formed, the pre-mRNA is cleaved. CsTF and the two cleavage factors leave the complex. PAP adds approximately 10 adenine nucleotides to the 3 end of the pre-mRNA molecule. The addition of the short poly(A) tail allows for the binding of the poly(A) binding protein (PABII) to the tail. PABII increases the rate of polyadenylation, which subsequently allows for more PABII protein to bind the tail

  

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