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TLS Online TPP Program

#Question id: 3988

The tryptophan operon of E. coli is repressed by tryptophan added to the growth medium.  The tryptophan repressor probably:

#Unit 3. Fundamental Processes

  1. binds to RNA polymerase when tryptophan is present.

  2. binds to the trp operator in the absence of tryptophan.

  3. binds to the trp operator in the presence of tryptophan.

  4. is a DNA sequence.

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TLS Online TPP Program

#Question id: 3374

#Unit 11. Evolution and Behavior

Consider an autosomal locus with two alleles A1 and A2 at frequencies of 0.6 and 0.4 respectively. Each generation, A1 mutates to A2 at a rate of μ = 1 x 10-2 while A2 mutates to A1 at a rate of υ = 1 x 10-1) Assume that the population is infinitely large and no other evolutionary force is acting. The overall change in allelic frequency will be
TLS Online TPP Program

#Question id: 5580

#Unit 5. Developmental Biology

The innermost layer of the root cortex is the
TLS Online TPP Program

#Question id: 1133

#Unit 4. Cell Communication and Cell Signaling

What tertiary structure characterizes all cytokines?
TLS Online TPP Program

#Question id: 11297

#Unit 10. Ecological Principles

What is the difference between gross and net primary production?
TLS Online TPP Program

#Question id: 12767

#Unit 10. Ecological Principles

Your friend comes to you with a problem. It seems his shrimp boats aren’t catching nearly as much shrimp as they used to. He can’t understand why because originally he caught all the shrimp he could handle. Each year he added a  new  boat,  and  for  a  long  time  each  boat  caught  tons  of  shrimp.  As  he  added  more  boats,  there  came  a  time when each boat caught somewhat fewer shrimp, and now, each boat is catching a lot less shrimp. Which of the following topics might help your friend understand the source of his problem?