Answer:
Explanation:
Transcription takes place in nucleus in the presence of the enzyme RNA polymerase.
During transcription, the code present in DNA gets transcribed into the code in mRNA. (messenger RNA)
RNA even though is a single stranded shows base pairing.
The pre-mRNA gets created from the DNA.
DNA has two strands, one of these strands acts as coding and another non coding strand.
The DNA shows base pairing with AGTC. [A-Adenine, G- Guanine, T-Thymine and C- Cytosine]
Whereas mRNA base pairing with AGUC. [ U- Uracil ]
Here in mRNA, instead of thymine, uracil gets paired.
According to base pairing of coding strand/sense strand of DNA, complementary bases pairs in 5'---->3' direction in mRNA.
The mRNA created looks exactly like the non-coding strand/sense strand of DNA except instead of thymine, uracil gets replaced.
The pre-RNA undergoes splicing, capping and tailing to form mature mRNA.
Answer: D) cAMP
Explanation:
In the absence of glucose cell can make use of other sources of carbohydrates such as lactose. In E. Coli and other bacteria utilization of lactose depends on the availability of cAMP. Bacteria accumulate cAMP only when starved. When glucose is exhausted, cAMP is available in plenty.
cAMP is necessary for the gene expression because it binds catabolite repressor protein (CAP) to form CAP-cAMP complex. CAP is a lac repressor the binds to the operator site of the lac operon preventing RNAP From binding to the promoter.
RNA polymerase can bind to the promoter site only when CAP-cAMP formed
