#Question id: 4090
#Unit 3. Fundamental Processes
Tryptophan synthesis can be controlled by a process called attenuation in which the levels of tryptophan in the cell control translation by
#Question id: 4091
#Unit 3. Fundamental Processes
To avoid being degraded by nuclear exonucleases, nascent transcripts, pre-mRNA-processing intermediates, and mature mRNAs in the nucleus must have their ends protected. Which of the following mechanism are present in the cell to protect mRNA from degradation?
I. The 5′ cap is protected because it is bound by a heterodimeric nuclear cap-binding complex (CBC), which protects it from 5′ exonucleases and also functions in export of the mRNA to the cytoplasm.
II. 5’-5’ phosphodiester bond in the cap of mRNA plays crucial role in protection
III. The 3′ end of a nascent transcript lies within the RNA polymerase and is thus inaccessible to exonucleases
#Question id: 4092
#Unit 3. Fundamental Processes
An experimental setup provided the assay for identifying factors that facilitate transcription in the presence of chromatin. A factor called FACT (facilitates chromatin transcription) functions as
#Question id: 4093
#Unit 3. Fundamental Processes
Which of the following processes is NOT an example of allosteric regulation?
#Question id: 4094
#Unit 3. Fundamental Processes
The accompanying figure depicts the map of a part of E. coli genome harboring the lac operon.
lac mRNA would hybridize to which of the following DNA?
1) lac I; 2) lac 0; 3) lac Z; 4) lac Y; 5) lac A
#Question id: 4095
#Unit 3. Fundamental Processes
Many eukaryotic genes contain a large number of exons. Correct splicing of such genes requires that neighboring exons be ligated to one another; if they are not, exons will be left out. One early proposal suggested that the splicing machinery bound to a splice site at one end of an intron and scanned through the intron to find the splice site at the other end. Such a scanning mechanism would guarantee that an exon was never skipped. This hypothesis was tested with one minigene with a duplicated 3ʹ splice site. Find diagram of the products you expect from minigene if the splicing machinery binds to a 3ʹ splice site and scans toward a 5ʹ splice site.