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TLS Online TPP Program

#Question id: 15524

The bulk of DP thymocyte death (~95%) occurs among thymocytes that fail positive selection because 

#Unit 4. Cell Communication and Cell Signaling
  1. Their receptors specifically recognize self-MHC molecules with intermediate affinity
  2. Their receptors specifically recognize self-MHC molecules
  3. These cells receive survival signals through their TCRs, and die by a process known as death by neglect.
  4. Their receptors do not specifically recognize self-MHC molecules
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TLS Online TPP Program

#Question id: 14737

#Unit 2. Cellular Organization

Which structures are involved in formation of biofilms
TLS Online TPP Program

#Question id: 14760

#Unit 2. Cellular Organization

During the microfilament formation, the nucleation phase is marked by:
TLS Online TPP Program

#Question id: 14761

#Unit 2. Cellular Organization

Following graph represent phases of in vitro G-actin polymerization.



Which of the following is correct?
TLS Online TPP Program

#Question id: 14762

#Unit 2. Cellular Organization

Following statements are regarding to determination of filament formation by actin concentration.
A. The critical concentration (Cc) is the concentration at which G-actin monomers are in equilibrium with actin filaments.
B. At monomer concentrations below the Cc, no polymerization takes place. 
C. When polymerization is induced at monomer concentrations above the Cc, filaments assemble until steady state is reached and the monomer concentration falls to Cc.
D. At steady state, the concentration of monomeric actin below the critical concentration.
Which of the following statements promotes spontaneous filament assembly?
TLS Online TPP Program

#Question id: 14763

#Unit 2. Cellular Organization

Which of the following graph shows G-actin polymerize into F-actin.
 
TLS Online TPP Program

#Question id: 14764

#Unit 2. Cellular Organization

Match the following proteins (Column I) with their function (Column II). Which of the following is correct?

Column I

Column II

a. Profilin

i. binds to the (+) end of an actin filament, thereby inhibiting subunit addition or loss.

 

b. Cofilin

ii. blocks (−) ends, inhibits filament disassembly, to stabilize filaments

c. Thymosin-β4

iii. involved in actin treadmilling, but it binds specifically to F-actin in which the subunits contain ADP

d. Cap Z

iv. binds ADP–G-actin and catalyzes the exchange of ADP for ATP

e. Tropomodulin

v. binds to ATP–G-actin in such a way that it inhibits addition of the actin subunit to either end of the filament.