Question

The macromolecular complex that associates with each intron and splices it is called a(n). splicer acrosome splice engine spliceosome splicing body

Answer 1

Answer for question number 1 : The correct option is D ( spliceosome)

Explanation: Spliceosomes are the large protein complexes which bring about the splicing of introns during post transcriptional modifications of eukaryotic mRNA. The spliceosome is made up of specialized RNA-protein complexes, small nuclear ribonucleoproteins. Each snRNP contains one of a class of eukaryotic RNAs, 100 to 200 nucleotides long, known as small nuclear RNAs (snRNAs). Five snRNAs (U1, U2, U4, U5, and U6) involved in splicing reactions are generally found in abundance in eukaryotic nuclei.

Answer for question number 2 : The correct option is E ( Both 1 and 2 are correct). Transcription results in the synthesis of mRNA not cDNA.

Explanation :

Promoters are the transcription intiation sites present in the DNA which can be bound by the RNA polymerase to intiate transcription process. TATAAT , TTGACA and UP elements are -10 and -35 and -40 to -60 promoter sequences found in the prokaryotic organisms.

Sigma subunit/Factor plays an important role in directing the RNA polymerase to bind to specific sites on DNA molecules called promoters and also reduces the affinity of RNAP for non specific sites on DNA during transcription.

There are various sigma factors which works at different conditions such as

Sigma 70 : Which is also called as primary sigma factor which is involved in the transcription ofmost of the genes.

Sigma 32 : Which is involved in the transcription of heat shock proteins. This occurs when a bacteria is subjected to higher temperatures.