TLS Online TPP Program

#Question id: 15780


In drosophila, the somatic cells of the hub are able to regulate stem cell proliferation by secreting the paracrine factor Unpaired onto the cells attached to them. Unpaired activates the JAK-STAT pathway in the adjacent germ stem cells to specify their self-renewal. Those cells that are distant from the paracrine factor cannot receive this signal, they begin their differentiation into the sperm cell lineage. This means hub cells act as

#Unit 5. Developmental Biology
  1. Stem cell niches allow controlled self-renewal and also survival of the cells that leave the niche.
  2. Stem cell niches not allow controlled self-renewal but allow survival of the cells that leave the niche.
  3. Stem cell niches allow uncontrolled self-renewal and also division of the cells that leave the niche.
  4. Stem cell niches allow controlled self-renewal and regulate the ratio of cell division to differentiation.
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TLS Online TPP Program

#Question id: 4413

#Unit 3. Fundamental Processes

Which of the following is true about TFIID?

TLS Online TPP Program

#Question id: 4414

#Unit 3. Fundamental Processes

The helicase of TFIIH hydrolyzes the β-γ bond of ATP to catalyze open complex formation at Pol II promoters. ATP hydrolysis is also required by a step subsequent to transcription initiation, most likely promoter clearance. Transcriptional activation by TFIIH was assayed on linear and circular templates either in the presence of ATP and GTP or the nonhydrolyzable nucleotide analogs AMP-PNP and GMP-PNP with RNA Polymerase I. The following results were obtained. Choose plausible explanation for these results. 

A. ATP is required under conditions where TFIIH is indispensable for initiation. These conditions include transcription from promoters containing a short stretch of mismatched base pairs surrounding the transcriptional start site as well as on negatively supercoiled templates.

B. As Pol I transcription on linear templates requires neither ATP hydrolysis nor protein phosphorylation

C. in contrast to Pol II, the topology of the template does not affect the requirement for TFIIH and neither the ATPase, helicase, nor protein kinase activity of TFIIH are required for Pol I transcription activation.

TLS Online TPP Program

#Question id: 4415

#Unit 3. Fundamental Processes

PML nuclear bodies are also sites of post-translational modification of proteins through the addition of

TLS Online TPP Program

#Question id: 4416

#Unit 3. Fundamental Processes

The minor spliceosome recognizes rarely occurring introns having consensus sequences distinct from the sequences of most pre-mRNA introns. It should be emphasized that although these introns are rare, they are distributed in genome with frequency of

TLS Online TPP Program

#Question id: 4417

#Unit 3. Fundamental Processes

In eukaryotes, at most promoters, Pol II pauses after transcribing fewer than 100 nucleotides, due to the binding of

TLS Online TPP Program

#Question id: 4418

#Unit 3. Fundamental Processes

Histones in repressed regions near telomeres and at the silent mating loci are hypoacetylated, confirmed by using