DNA-Transcription & Regulation Of Gene Expression 1

Question 1

RNA poly 1&2&3 are specific to?

Answer 1

Prokaryotes

Question 2

Which of the following are non-coding?
A. mRNA
B. Trna
C.rRna

Answer 2

tRNA & Rrna

Question 3

Within eukaryotic cells what are two post transcriptional modifications done to the mRNA sequence?

Answer 3

The addition of a five prime Methyl cap and 3’ Poly a tail

Question 4

Your patient is underling new cancer treatment in which target the histone proteins, specifically one of the covalent modifications. This essentially intiates a repulsion charge. Which of the following molecular structures is most likely involved?

A. Leucine
B. Isoleucine 
C. Lysine
D. Methyl 
E. Histidine

Answer 4

C. Lysine

This is well attempting to describe acetylation of lysine within the Histone to to remove the positive charges therefore increase the repulsion, therefore causing the unwinding of the DNA, causing the Heterochromatin

Question 5

If designing a drug for the initiation process of transcription of prokaryotes which of the following sites would look for?

A. Promoter(-35 Sequence)
B. Sigma Factor
C. Pribnow Box
D. Intiations Factors

Answer 5

A. Promoter (-35 Sequence)
B. Sigma Factor

Here there 2 correct answers. The reason is that there 2 answers is because when looking at the invitation process. We see that the holoenzymes attaches down with sigma, to begin the initiation process therefore. If it By blocking the Promoter region(-35 Sequence) the Sigma can’t not attach along side the holoenzyme.

Secondly if by blocking the Sigma factors the holoenzyme is therefore incomplete. This as a result is the causes the the initiation process to come to a halt.

Question 6

When looking to the different mechanisms in which genes are repressed, you use the example of Lac Operon to your Med 1 Students. As a result you explain to them that when in the presence of glucose the lac gene is turned off. While not in the presence of glucose but in the presence of lactose, which molecules binds where, and for what function, following the consumption of drinking milk?

A. Promoter site- to begin making the DNA to code for more proteins
B. The CAMP binding to CAP therefore binding to the CAP site,- which moves the repressor from the operon
C. A disarchirde sugar binds to the repressor therefore removing it from the from the operator.
D. Adenyl Cyclase binding to the CAMP therefore binding CAP to the Cap site therefore allowing for the RNA Polymerase to continue
E. A disarchirde sugar Causing a confirmational change in which binds to the repressor therefore Binding to removing it from the from the operator.

Answer 6

E. The presence of lactose a disarchride sugar,(glucose and galactose) causing an iso form known as allylactose to bind to the repressor therefore removing it and the production of lactase is produced. Once glucose is sufficient there is no longer an isoform of the molecule therefore the repressor sitting on the operator region preventing the production of DNA for this molecule.

This is a classic example of Gene Expression within prokaryotes