TLS Online TPP Program

#Question id: 1386


The ability of a population of fibroblasts to migrate along the surface of a tissue culture dish depends on adhesion between the cell surface and the extracellular matrix molecules coating the dish. The dish is coated with laminin, and the only cell-surface protein capable of binding laminin is a cell-adhesion protein called an integrin. Integrins are integral plasma-membrane proteins that function as heterodimers. Under these conditions the rate at which a fibroblast can migrate along the laminin coated culture dish is proportional to the strength of adhesion between the cell and the laminin substrate. The table below lists the rate of cell migration observed for fibroblasts genetically engineered to generate the indicated phenotypes. One explanation for the effect of overexpression of the cytoplasmic domain of the integrin beta subunit is that this domain normally functions to bind a cytoplasmic factor necessary for integrin function. Which of the following would be the most informative experiment to identify the cytoplasmic factor?

#Unit 4. Cell Communication and Cell Signaling
  1. Fractionate a fibroblast cell extract using an affinity column prepared with the cytoplasmic domain of the beta integrin subunit.

  2. Fractionate a fibroblast cell extract using an affinity column prepared with the integrin beta subunit lacking the cytoplasmic domain.

  3. Inject live fibroblasts with the cytoplasmic domain of the integrin beta subunit.

  4. Inject live fibroblasts with an antibody to the cytoplasmic domain of the integrin beta subunit.

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TLS Online TPP Program

#Question id: 3428

#Unit 11. Evolution and Behavior

In a sample from an African population, the frequency of blood group allele IA, IB and IO were 0.30, 0.20 and 0.50 respectively. What is expected frequency of A and B blood group respectively when population size 1000?

TLS Online TPP Program

#Question id: 3427

#Unit 11. Evolution and Behavior

Natural selection can alter the frequency of distribution allele and heritable trait in different following way

A- Accumulation of those mutation that increase fitness of population in changing environment

B- Check accumulation of mutation that lower the fitness of species in unchanging environment

c- occur when population is subjected to divergent selection

TLS Online TPP Program

#Question id: 3426

#Unit 11. Evolution and Behavior

Fitness of three different genotypes is given in population I and II, under natural selection which of the following statement are correct?

TLS Online TPP Program

#Question id: 3425

#Unit 11. Evolution and Behavior

Many evolutionary forces are operating in population. In study, within population increase genetic variation due to -----A-----while decrease genetic variation due to ------B-----. Between populations increase genetic variation due to -----C-----while decrease genetic variation due to ------D-----.

TLS Online TPP Program

#Question id: 3424

#Unit 11. Evolution and Behavior

Which of the following statement is correct? 

A. Darwin, theory of natural selection based on better-adapted organisms would acquire more resources and leave more offspring.

B. When population sizes become too small, individuals accumulate deleterious (harmful) mutations, and survival of offspring is threatened

C. Inbreeding is more likely to take place in nature when population size becomes very small and the number of mates is limited.

D. Effective population size can be reduced by harem mating structures

E. The movement of a few individuals between populations can counteract the effects of genetic drift

TLS Online TPP Program

#Question id: 3423

#Unit 11. Evolution and Behavior

Following statement regarding divergent evolution?

A- Spreading of same species to different and isolated environments which blocks the gene flow among the distinct populations

B. vertebrate limb of whale and elephant is one example of divergent evolution

C- Both orthologous genes and paralogous genes can be said to display divergent evolution

D- Sympatric speciation leads to divergence of one species in to two are more descendant species

Which of the following combination of above statement are correct?