BIOS-115 Lecture 6: BIOS 115 lecture 6

Indicate whether eac is true for gene expression in prokaryotes,eukaryotes or both:

1. After transcription, a 3' poly- A tail and a 5' cap areaddeddto the RNA.

2. Translation of mRNA can begin before transcription iscomplete.

3. RNA polymerase binds to the promoter region to begintranscription

4. RNA polymerase can only add a robonucleotide to the 3' end ofthe growing RNA

5. The mRNA transcript is the exact complement of the gene fromwhich it was copied.

Indicate whether eac is true for gene expression in prokaryotes,eukaryotes or both:

1. After transcription, a 3' poly- A tail and a 5' cap areaddeddto the RNA.

2. Translation of mRNA can begin before transcription iscomplete.

3. RNA polymerase binds to the promoter region to begintranscription

4. RNA polymerase can only add a robonucleotide to the 3' end ofthe growing RNA

5. The mRNA transcript is the exact complement of the gene fromwhich it was copied.

In Xenopus 4,000 cell blastula embryos, cells transcribe the whittled (Wtl) gene. In all cells the same primary RNA is transcript can be found in cell nuclei, in fact this transcript is processed to produce the same mRNA in all cells. However in the animal cap cells, there is 10 fold less mRNA than in vegetal cells, resulting in production of more whittled protein in vegetal cells. How is whittled gene expression controlled? Transcriptional, post-transcriptional, translational, or post-translational level. For the level that you choose, be as specific as possible and describe one mechanism that could be operating at this level.