DNA replication is studied in a newly discovered bacterium. It takes 30 min for the bacterium to complete a round of replication at 37oC. A Meselson-Stahl-type experiment was performed. The bacteria were grown for several generations in 14N-medium and then switched to 15N-medium. The DNA molecules were then analyzed.

If the mechanism of DNA replication in this bacterium were semi-conservative, what results would be found when the double-stranded DNA was analyzed in a CsCl density gradient after three generations in 15N-medium?

#Question id: 4498

#Unit 3. Fundamental Processes

Which enzyme is used in this particular mechanism;

#Question id: 4499

#Unit 3. Fundamental Processes

The final RNA processing event, polyadenylation of the 3’end of the mRNA, is intimately linked with the termination of transcription. Just as with capping and splicing, the polymerase CTD tail is involved in recruiting some of the enzymes necessary for polyadenylation,

#Question id: 4500

#Unit 3. Fundamental Processes

The free end of the second RNA is uncapped and thus can be distinguished from genuine transcripts. This new RNA is recognized by an RNase called, in yeast, _ and in humans_ that is loaded onto the end of the RNA by another protein that binds the CTD of RNA polymerase.

#Question id: 4501

#Unit 3. Fundamental Processes

According to Models of termination: torpedo and allosteric, which one is now the favored and why;

A. The Rat1 enzyme is very processive and quickly degrades the RNA in a 5’ -to-3’ direction, until it catches up to the still-transcribing polymerase from which the RNA is being spewed.

B. Termination depends on a conformational change in the elongating polymerase that reduces the processivity of the enzyme leading to spontaneous termination soon afterward.

#Question id: 4502

#Unit 3. Fundamental Processes

Which one is the only GTF that is used by Pol I and Pol III as well as by Pol II, it has emerged recently that some of the other GTFs

#Question id: 4503

#Unit 3. Fundamental Processes

Pol I transcribes the human rRNA genes, the promoter for the rRNA gene comprises two parts: the core element and the UCE (upstream control element), for initiation there are two factors-