Problem:

Question 1: Which of the following statements is NOT true?

a) in a eukaryotic mRNA, the poly-A tail promotes degradation of the molecules

b) the longer the lifetime of an mRNA, the more protein can be produced from it.

c) many eukaryotic mRNAs have a longer lifetime than bacterial mRNAs

d) the different lifetimes of eukaryotic mRNAs are controlled in part by nucleotide sequences in the mRNA itself.

Question 2: In bacteri, if a protein binds to the ribosomal binding site on an mRNA, what is the consequences?

a) the protein will recruit te small ribosomal subunit to the mRNA, increasing translation efficiency.

b) the small ribosomal subunit will not be able to bind to the mRNA, and translation will be inhibited.

c) the ribosome will begin translation at a new location on the mRNA.

Question 3: Which of the following describes the lac operon in E. coli when lactose, but not glucose, is present in the culture medium?

a)CAP, but not the lac repressor, is bound to the lac operons regulatory DNA, and the lac operon is expressed.

b) the lac repressor, but not CAP, is bound to the lac operons regulatory DNA, and the lac operon is not expressed

c)neither CAP nor the lac repressor is bound to the lac operons regulatory DNA, and the lac> operon is not expressed

d)CAP and the lac repressor are both bound to the lac operons regulatory DNA, and the lac operon is not expressed.

Give reasoning with your answer.