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TLS Online TPP Program

#Question id: 1260

Which of the following statement regarding RTK/Ras pathway is incorrect?

#Unit 4. Cell Communication and Cell Signaling

  1. Receptor activation leads to re-localization of Sos from the cytosol to the membrane, which brings Sos close to its substrate, Ras∙GDP, which is already bound to the plasma membrane by means of a covalently attached lipid.

  2. Binding of Sos to Ras∙GDP leads to conformational changes in the switch I and switch II segments of Ras, thereby opening the binding pocket for GDP so it can diffuse out.

  3. The SH2 domains in GRB2 selectively bind to proline-rich sequences in Sos; different SH3 domains in other proteins bind to proline-rich sequences distinct from those in Sos.

  4. Ras is activated by the exchange of GDP for GTP. Active Ras∙GTP binds to the N-terminal regulatory domain of Raf, a serine/threonine kinase, thereby activating its kinase activity.

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TLS Online TPP Program

#Question id: 23180

#Unit 13. Methods in Biology

FRET is very sensitive to small changes in distance and in practice is not detectable at distances greater than 
TLS Online TPP Program

#Question id: 23179

#Unit 13. Methods in Biology

In order to observe FRET two flurophores must be in close proximity of about 10nm distance. Given below are few flurorescent molecules.
1. YFP
2. RFP
3. GFP
4. CFP
Which option below contains correct combination of flurorescent molecules that can give FRET?
TLS Online TPP Program

#Question id: 23173

#Unit 13. Methods in Biology

There are various drawbacks still in fluorescence microscopy such as
1.  Light emitted comes from molecules above and below the plane of focus
2. Blurred image due to superposition of fluorescent images
Which of the above statement is/ are correct?
TLS Online TPP Program

#Question id: 23170

#Unit 13. Methods in Biology

Which epitope tags can be used to tag recombinant proteins?
1. FLAG
2. myc
3. TICK
Which of the following options is incorrect?
TLS Online TPP Program

#Question id: 23168

#Unit 13. Methods in Biology

What are the advantages of using secondary antibodies in indirect immunofluorescence?
1.  It makes easy to choose a different conjugate no matter the primary antibody
2. Enhance detection by localizing more conjugate at the antigen
3. Conjugation of fluorophore can interfere with the primary antibody’s recognition of the antigen
Which of the following options is correct?
TLS Online TPP Program

#Question id: 23166

#Unit 13. Methods in Biology

To visualize two proteins in fixed Hela cells using an epifluorescence microscope. Below is a list of various fluorophores (dyes) available to see those proteins.
1. FITC
2. GFP
3. Fluorescein
4. Alexa 568
Select the correct combinations of the appropriate dyes that would typically be utilized to observe co-localization in an epifluorescence microscope?