TLS Online TPP Program

#Question id: 15524


The bulk of DP thymocyte death (~95%) occurs among thymocytes that fail positive selection because 

#Unit 4. Cell Communication and Cell Signaling
  1. Their receptors specifically recognize self-MHC molecules with intermediate affinity
  2. Their receptors specifically recognize self-MHC molecules
  3. These cells receive survival signals through their TCRs, and die by a process known as death by neglect.
  4. Their receptors do not specifically recognize self-MHC molecules
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TLS Online TPP Program

#Question id: 3367

#Unit 11. Evolution and Behavior

The largest unit within which gene flow can readily occur is a

TLS Online TPP Program

#Question id: 3368

#Unit 11. Evolution and Behavior

The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of

TLS Online TPP Program

#Question id: 3369

#Unit 11. Evolution and Behavior

Genetic drift refers to random changes in allele frequencies over time leads to following consequence

a. Loss of genetic diversity per generation   

b. change in allelic frequency just by chance 

c. It caused adaptive evolution

d. It one allele may reach to 0 frequency

TLS Online TPP Program

#Question id: 3370

#Unit 11. Evolution and Behavior

One thousand independent populations of Drosophila are established with 25 individuals in each population, of which, one individual is of Aa genotype and the other nine are of AA genotype. If random genetic drift is the only mechanism acting on these populations, then, after a large number of generations, the expected number of populations fixed for the "a" allele is

TLS Online TPP Program

#Question id: 3371

#Unit 11. Evolution and Behavior

If a given gene in a randomly mating population has three alleles a, b and c in the ratio of 0.6, 0.3 and 0.1 respectively, what is the expected frequency of all heterozygote?

TLS Online TPP Program

#Question id: 3372

#Unit 11. Evolution and Behavior

Fish, penguin and Dolphin are independently evolved similar traits as a result of having to adapt to similar environments or ecological niches.

A. On a molecular level, this can happen due to random mutation in unrelated taxon to adaptive changes

B. This is the example of divergent evolution, occurred due to similar group of organisms inhabiting different environments

C. Similar phenotype are produced by identical change in orthologous gene

D. This is the example of convergent evolution, occurred due to similar group of organisms inhabiting different environments

Which of the following is the correct combination?