Practice Questions

  1. Home
  2. Free Resources
  3. Practice Questions
  4. 14264
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.
More Questions
TLS Online TPP Program

#Question id: 17654

#Unit 14. Methods in Biology

The protein concentration in DNA extraction sample measured by
TLS Online TPP Program

#Question id: 17655

#Unit 14. Methods in Biology

In DNA isolation, for protein free solution what will be the ratio at  nm
TLS Online TPP Program

#Question id: 17659

#Unit 14. Methods in Biology

During your study of the gene for an enzyme you have isolated an amber mutation in the middle of the gene which produces a truncated form of the enzyme. By placing a +1 frameshift mutation a short distance before the amber mutation and a –1 frameshift mutation a short distance after the amber mutation you create a triple mutant that restores expression of a functional, full-length enzyme. 
a) +1 frameshift puts the amber mutation out of frame so that it is no longer read as a stop.
b) -1 frameshift is inserted after the amber so that no longer read as a stop.
c)  -1 frameshift is inserted after the amber to restore the frame of the end of the protein.
d) +1 frameshift puts the amber mutation out of frame so that it restore the frame of the end of the protein.
Which of the following is the correct prediction about the frame shift mutation?
TLS Online TPP Program

#Question id: 17819

#Unit 14. Methods in Biology

During RNA extraction, the homogenate is first treated with
TLS Online TPP Program

#Question id: 17820

#Unit 14. Methods in Biology

During the RNA extraction guanidinium thiocyanate functions as a strong inhibitor of
TLS Online TPP Program

#Question id: 17997

#Unit 14. Methods in Biology

In RNA isolation, for protein free solution what will be the ratio at  nm