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TLS Online TPP Program

#Question id: 4373

Which of the following is true about transcription?

#Unit 3. Fundamental Processes

  1. A repressor protein activates transcription of a negatively regulated gene.

  2. A positively regulated gene can be transcribed only in the absence of active repressor.

  3. In the absence of an activator, a negatively regulated gene is poorly transcribed.

  4. The initiation of transcription of regulated genes is controlled by regulatory proteins which bind to specific DNA sequences.

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TLS Online TPP Program

#Question id: 5000

#Unit 11. Evolution and Behavior

The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that
TLS Online TPP Program

#Question id: 15638

#Unit 13. Methods in Biology

You have isolated two mutations that show decreased expression of the Lac operon. However, unlike like the promoter mutations, these mutations don’t respond to the inducer IPTG. These mutations, designated Lac3– and Lac4–, are evaluated for the quantity of ß-galactosidase and permease activity expressed with or without IPTG:
 
Mapping experiments reveal that Lac3– and Lac4– are different short deletions located in the region before the start of the LacZ gene. Given the data shown above suggest which genetic element(s) in addition to part of the promoter has been deleted in each mutant. 
TLS Online TPP Program

#Question id: 2494

#Unit 2. Cellular Organization

Separation of spindle poles during spindle formation and anaphase B most likely depends on which of the following?
TLS Online TPP Program

#Question id: 15239

#Unit 13. Methods in Biology

Which of the following are the three important components of gel Electrophoresis 
a) Current applied
b) Buffer system used 
c) Gel concentration 
d) Surface of electrophoresis kit
TLS Online TPP Program

#Question id: 4448

#Unit 3. Fundamental Processes

Three defined steps in a transcription cycle; choose correct one

1a. Closed complex

In this form, the DNA remains double-stranded, and the enzyme is bound to one face of the helix. I

1b. Open complex

In which the DNA strands separate over a distance of 13 bp around the start site to form the transcription bubble. In the next stage of initiation,

2. Promoter escape

Incorporation of the first 10 or so ribonucleotides is a rather inefficient process, and at that stage, the enzyme often releases short transcripts and then begins synthesis again

3. Initial transcribing complex.

Once an enzyme makes a transcript longer than 10 nucleotides, it is said to have