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TLS Online TPP Program

#Question id: 16147

 Which statement is not true for Natural killer (NK) cells?

#Unit 4. Cell Communication and Cell Signaling
  1. Natural killer (NK) cells are lymphoid cells that are closely related to B and T cells. However, they do not express antigen specific receptors and are considered part of the innate immune system.
  2. They are distinguished by the expression of a surface marker known as NK1.1, as well as the presence of cytotoxic granules. Once referred to as “large granular lymphocytes” because of their appearance under a microscope.
  3.  NK cells constitute 5% to 10% of lymphocytes in human peripheral blood. Th ey are effi cient cell killers and attack a variety of abnormal cells, including some tumor cells and some cells infected with virus.
  4. They distinguish cells that should be killed from normal cells in a very clever way: by “recognizing” the absence of MHC class II, which is expressed by almost all normal cells, but is specifically down-regulated by some tumors and in response to some viral infections.
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TLS Online TPP Program

#Question id: 10891

#Unit 10. Ecological Principles

In a lake ecosystem with three trophic levels - Phytoplankton (P), Zooplankton (Z) and Carnivore (C) is control by bottom-up effects, which of the following observation is incorrect?
TLS Online TPP Program

#Question id: 10892

#Unit 10. Ecological Principles

Considering environment and ecosystem, identify the INCORRECT statement
TLS Online TPP Program

#Question id: 11265

#Unit 10. Ecological Principles

Approximately how many kg of carnivore production can be supported by a field plot containing 2000 kg of plant material?
TLS Online TPP Program

#Question id: 11266

#Unit 10. Ecological Principles

Which of the following options lists ecosystems in increasing order of consumption efficiency of herbivore?
TLS Online TPP Program

#Question id: 11276

#Unit 10. Ecological Principles

Following statement regarding efficiency at different tropic level for secondary production?

A-high production efficiency individual able to survive at little food

B-production efficiency decrease toward increase tropic level 

C-aquatic herbivore is more efficient grazer than terrestrial grazer

D- Carnivore assimilation efficiency appear to average around 10%

Which above combination are correct?
TLS Online TPP Program

#Question id: 11277

#Unit 10. Ecological Principles

If a species is a keystone predator, then its removal from a community should

(A) Increase population size of the predator’s preferred prey

(B) decrease species diversity in the prey community

(C) decrease productivity of the predator’s preferred prey

(D) increase species diversity in the prey community