Two trains is moving in opposite directions at 70 kmph and at 80 kmph. Their lengths are 1.3 km and 0.7 km respectively. The time taken by the slower train to cross the faster train in seconds is:

#Question id: 4398

#Unit 3. Fundamental Processes

Which of the following are not found in DNA-binding proteins?

#Question id: 4399

#Unit 3. Fundamental Processes

Transcription factors can

a. exhibit cooperative binding.  b. exist as heterodimers.

c. act to repress transcription of transcription factor genes.

d. undergo conformational changes which alter activity.

e. never interact with co-repressors.

#Question id: 4400

#Unit 3. Fundamental Processes

Which is the first factor to bind at the promoter of eukaryotic genes?

a. RNA polymerase

b. TFIIA

c. TFIIB

d. TFIID 

e. TATA box–binding protein

#Question id: 4401

#Unit 3. Fundamental Processes

Which of the following occur(s) during Pol II transcription preinitiation complex formation?

a. TFIIA binds to TFIIB.  b. TFIIB unwinds the DNA.

c. TFIIB contacts both TATA box–binding factor and DNA.

d. DNA bends.

#Question id: 4402

#Unit 3. Fundamental Processes

Chromatin-mediated repression of transcription involves

a. modification of lysine residues in histones. 

b. large, multiprotein complexes.

c. acetylation of histone tails.   

d. deacetylation of histone tails.

#Question id: 4403

#Unit 3. Fundamental Processes

 Which of the following does (do) not require a DNA helicase activity?

a. SWI/SNF function  b. Pol II open-complex formation

c. transcription-factor binding to DNA

d. deacetylation of histone tails