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TLS Online TPP Program

#Question id: 15656

You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium. Explain the two regulatory pathways for Mel1 that can explain the behavior of the MelA– and MelB– mutations. For each regulatory pathways what is a role for the inducer melibiose?

#Unit 13. Methods in Biology
  1. melibiose and MelB both have a net negative effect on Mel1 activity, and MelA has a net positive effect on Mel1 activity.
  2. melibiose and MelB both have a net positive effect on Mel1 activity, and MelA has a net negative effect on Mel1 activity.
  3. melibiose and MelB both have a net positive effect on Mel1 activity, and MelA also has a net positive effect on Mel1 activity.
  4. melibiose and MelB both have a net negative effect on Mel1 activity, and MelA also has a net negative effect on Mel1 activity.
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TLS Online TPP Program

#Question id: 5191

#General Aptitude

Find the sum of all even three digit numbers which are divisible by 3.
TLS Online TPP Program

#Question id: 26900

#Unit 10. Ecological Principles

Tundra is___
TLS Online TPP Program

#Question id: 10736

#Unit 10. Ecological Principles

Ecotones are:
TLS Online TPP Program

#Question id: 17267

#Unit 8. Inheritance Biology

In humans, albinism (unpigmented skin, hair, and eyes) is due to an enzymatic deficiency, and it is an autosomal recessive trait. Suppose that in a small country of one million people (“Generation 1”), there are 500 aa albinos and 9000 Aa heterozygous carriers. Estimate q, the frequency of allele a, in Generation 1. Show your calculations. 
TLS Online TPP Program

#Question id: 5233

#Unit 11. Evolution and Behavior

The most important feature that permits a gene to act as a molecular clock is ________.