TLS Online TPP Program

#Question id: 12252


In a study of interactions between plants, ants and caterpillars, the following experimental treatments were imposed: i) Control (both ants and caterpillars are present); ii) Ant removal; iii) Caterpillar removal; iv) Ant and caterpillar removal. Plus (+) indicates presence and minus (-) indicates absence on plants. The results for plant performance (growth) from this experiment  are shown in the figure below. Plant performance in all treatments were significantly different from each other. Based on these results, which of the following inferences is correct?


#Unit 10. Ecological Principles
  1. In the absence of caterpillars, ants negatively affected plant performance
  2. In the absence of ants, caterpillars positively affected plant performance 
  3. In the presence of caterpillars, ants negatively affected plant performance 
  4. In the presence of ants, caterpillars positively affected plant performance


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TLS Online TPP Program

#Question id: 2827

#Unit 2. Cellular Organization

Two related genes that are derived from a gene duplication event are considered to be

a. homologous.                                   

b. paralogous.

c. orthologous.                       

d. members of a gene family.

TLS Online TPP Program

#Question id: 2828

#Unit 2. Cellular Organization

A transcriptionally active gene compared with a transcriptionally inactive gene would be expected to

a. contain acetylated histones.           

b. contain unacetylated histones.

c. be sensitive to DNase I.                 

d. be resistant to DNase I.

TLS Online TPP Program

#Question id: 2829

#Unit 2. Cellular Organization

Scaffold-associated regions

a. are the chromosome attachment points for the mitotic spindle.

b. can insulate transcription units from each other.

c. are the points at which DNA interacts with histone proteins.

d. are found between transcription units.

TLS Online TPP Program

#Question id: 2830

#Unit 2. Cellular Organization

The NtrC protein from E. coli
a. is a σ54 RNA polymerase.             
b. stimulates transcription of the glnA gene.
c. is activated by a protein kinase called NtrB.
d. binds both to an enhancer site upstream of the glnA gene and to RNA polymerase.
e. has ATPase activity.

TLS Online TPP Program

#Question id: 2831

#Unit 2. Cellular Organization

Specific DNA control elements in promoters can

a. interact with general transcription factors.

b. interact with repressor proteins.                 

c. interact with activator proteins.

d. remain unavailable because of condensed chromatin. 

TLS Online TPP Program

#Question id: 2832

#Unit 2. Cellular Organization

Reporter genes are used to

a. express enzymes that are not easily assayed in cell extracts.

b. express enzymes that are easily assayed in cell extracts.

c. characterize DNA control elements.                     

d. characterize reporter plasmids.