TLS Online TPP Program

#Question id: 1523


Following statements are regarding to the apoptosis which is induced by trophic factors.

A. The presence of specific trophic factors (e.g., NGF) leads to activation of their cognate receptor tyrosine kinases (e.g., TrkA) and activation of the PKB pathway.

B. DNA damage or ultraviolet irradiation leads to induction of synthesis of the BH3-only Puma protein. Puma binds to Bak and Bax as well as to Bcl-2, allowing Bak and Bax to form oligomeric pores.

C. Removal of a cell from its substratum disrupts integrin signaling, leading to release of the BH3-only Bim protein from the cytoskeleton.

D. Binding of extracellular death signals, such as tumor necrosis factor and Fas ligand, to their receptors oligomerizes an associated protein (FADD), which in turn triggers the caspase cascade, leading to cell murder by apoptosis.

Which of the following pathway does not belong to the trophic factor inducing apoptotic pathway?

#Unit 4. Cell Communication and Cell Signaling
  1. A only

  2. B and D

  3. C only

  4.  D only

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TLS Online TPP Program

#Question id: 13190

#Unit 10. Ecological Principles

During the evolution of life on Earth, the photosynthetic organisms initially responsible for raising atmospheric oxygen concentrations from less than 1 percent to about 20 percent were

TLS Online TPP Program

#Question id: 13189

#Unit 10. Ecological Principles

The relative abundance of C plant species increases with latitude because of the associated temperature gradient. A study in North America found that at  42°  North,  C3  plants  become more  abundant than  C4  plants. Given  an  increase in  mean global  temperatures by  10°C and no  other changes in  environmental conditions,  the latitude at which C3 plants become more abundant:

TLS Online TPP Program

#Question id: 13188

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance


Which of the following factors is most likely to generate the seed survivorship curve shown? 

TLS Online TPP Program

#Question id: 13187

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance


Which of the following factors is most likely to generate the seed density curve shown? 

TLS Online TPP Program

#Question id: 13186

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance

This model predicts that recruitment of new individuals into the population should be

TLS Online TPP Program

#Question id: 13185

#Unit 10. Ecological Principles

If a drop in sea level led Island 1 to double in area, the MacArthur-Wilson model predicts that the number of bird species found there would