TLS Online TPP Program

#Question id: 4713


A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these statements explains why the pigweed reappeared?

#Unit 11. Evolution and Behavior
  1. The herbicide company lost its triazine formula and started selling poor-quality triazine.

  2. Natural selection caused the pigweed to mutate, creating a new triazine-resistant species.

  3. Triazine-resistant pigweed has less-efficient photosynthesis metabolism.

  4. Triazine-resistant weeds were more likely to survive and reproduce.

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TLS Online TPP Program

#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

TLS Online TPP Program

#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.

TLS Online TPP Program

#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.

TLS Online TPP Program

#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

TLS Online TPP Program

#Question id: 4404

#Unit 3. Fundamental Processes

The yeast two-hybrid system can be used to identify

a. proteins that interact with a known or “bait” protein.

b. proteins that interact with a “fish” domain.

c. cDNAs that encode interacting proteins.

d. co-activators and co-repressors.

TLS Online TPP Program

#Question id: 4405

#Unit 3. Fundamental Processes

Which of the following can occur when steroid hormone binds to its cognate receptor?

a. conformational changes in the receptor

b. translocation of the receptor out of the cell membrane

c. binding of the receptor to DNA response elements

d. stimulation of transcription