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TLS Online TPP Program

#Question id: 16148

 Which statement is not true for NKT Cells?

#Unit 4. Cell Communication and Cell Signaling
  1. NKT cells, have received a great deal of recent attention and share features with both conventional T lymphocytes and NK cells.
  2. Like T cells, NKT cells have T-cell receptors (TCRs), and some express CD4. Unlike most T cells, however, the TCRs of NKT cells are not very diverse and recognize specific lipids and glycolipids presented by a molecule related to MHC proteins known as CD1.
  3. Like their innate immune relatives, NK cells, NKT cells have antibody receptors, as well as other receptors classically associated with NK cells. Activated NKT cells can release cytotoxic granules that kill target cells.
  4. they can not also release large quantities of cytokines that can both enhance and suppress the immune response. They appear to be involved in human asthma, but also may inhibit the development of autoimmunity and cancer
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TLS Online TPP Program

#Question id: 13138

#Unit 10. Ecological Principles

Life-history characteristics associated with K-selected ordgtanisms include K
TLS Online TPP Program

#Question id: 13137

#Unit 10. Ecological Principles

Reproductive value (Vx ) calculated from population life-table data provides a measure of the 
TLS Online TPP Program

#Question id: 13136

#Unit 10. Ecological Principles

The figure below illustrates the relationship between population density in the present generation (Nt) and population equilibrium density of this population in the next generation (Nt+1). The dashed reference line has a slope of 1. Which of the following represents equilibrium density of this population?
TLS Online TPP Program

#Question id: 13134

#Unit 10. Ecological Principles

Which  of  the  graphs  below  represents the  relationship between  population  size  (N)  and  population  growth  rate (dN/dt) for a population showing exponential growth?
TLS Online TPP Program

#Question id: 13133

#Unit 10. Ecological Principles

The diagram below depicts three general types of survivorship curves. Only the form of the curve is important, not its absolute scale. Which of the following statements is LEAST likely to be true?
TLS Online TPP Program

#Question id: 13132

#Unit 10. Ecological Principles

Biologists performed an experiment with flies to examine the effects of population size on the maintenance of genetic variation  and  on  egg-to-adult survival.  From  a  large  source  population, they  randomly  assigned  eggs  to  three experimental  populations  of  size  N,  equal  to  20,  60,  and0100.  For  later  generations,  they  collected  N  eggs  from each  population  and  moved  them  into  identical  vials  that  co0ntained  f2re0sh  me4d0ium.  Th6e0y  coun8te0d  the  number  of adult flies that emerged and used tissue samples from the adults for genetic analyses. Genetic variation was measured by  scoring  alleles  at  several  polymorphic  loci  and  expressed  as  the  average  number  of  alleles  at  those  loci.  The results are summarized in Figure 1 and Figure 2 below.

Which other process appears to have substantially influenced the outcome of this experiment?