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TLS Online TPP Program

#Question id: 13162

In the amoeba Dictyostelium discoideum, cAMP acts as an extracellular signalling molecule and binds to and signals via a G protein–coupled receptor; it is not a second messenger. Amoeba cells were transfected with genes encoding two fusion proteins: a Gα fused to cyan fluorescent protein (CFP), and a Gβ fused to yellow fluorescent protein (YFP). CFP normally fluoresces 490-nm light; YFP, 527-nm light. In which conditions fluorescence
energy transfer occur from CFP to YFP?

#Unit 4. Cell Communication and Cell Signaling
  1. If ligand binding occur it leads to association of the Gα and Gβγ subunits, then fluorescence energy transfer can occur.
  2. If ligand binding occur it leads to dissociation of the Gα and Gβγ subunits, then fluorescence energy transfer can occur.
  3. If ligand binding doesn’t occur (In resting state) it leads to dissociation of the Gα and Gβγ subunits, then fluorescence energy transfer can occur.
  4. If ligand binding doesn’t occur (In resting state) it leads to association of the Gα and Gβγ subunits, then fluorescence energy transfer can occur.
     
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TLS Online TPP Program

#Question id: 15339

#Unit 4. Cell Communication and Cell Signaling

HSCs begin their life in close contact with osteoblasts located close to the lining of the endosteal cavity. Once differentiated to the pre-pro-B-cell stage, the developing B cells require Which type of signals from the chemokine, which is secreted by a specialized set of stromal cells?
TLS Online TPP Program

#Question id: 15340

#Unit 4. Cell Communication and Cell Signaling

Serrogate light chain formation takes place in 
TLS Online TPP Program

#Question id: 15341

#Unit 4. Cell Communication and Cell Signaling

Formation of pre B-cell  describing__
A. Surrogate light chain formation 
B. On these surface present IgM
C. Heavy chain had been formed
D. DJ H chain recombination
TLS Online TPP Program

#Question id: 15342

#Unit 4. Cell Communication and Cell Signaling

The heavy chain is then expressed on the cell surface in combination with the surrogate light chain, which is made up of_______________, together they form the pre-B-cell receptor,
TLS Online TPP Program

#Question id: 15360

#Unit 4. Cell Communication and Cell Signaling

The cytochrome P450 constitute a superfamily of heme-containing enzymes that occur in nearly all living organisms, from bacteria to mammals, These monooxygenases, which in animals are embedded in the endoplasmic reticulum membrane, catalyze reactions of the sort
                  RH + O2 + 2 H+ + 2e− → ROH + H2O 
The electrons (e−) are supplied by NADPH, which passes them to cytochrome P450’s heme prosthetic group via the intermediacy of the enzyme NADPH P450 reductase. Here RH represents a wide variety of usually lipophilic compounds for which the different cytochromes P450 are specific. They include
a. polycyclic aromatic hydrocarbons 
b. polycyclic biphenyls
c. frequently carcinogenic compounds that are present in tobacco smoke, broiled meats, and other pyrolysis products
d. which were widely used in electrical insulators and as plasticizers and are also carcinogenic.
TLS Online TPP Program

#Question id: 15361

#Unit 4. Cell Communication and Cell Signaling

The chemical benzo(a)pyrene, found in cigarette smoke as well as in coal tar, undergoes metabolic activation in the lungs to form a potent mutagen that mainly, causes conversion of guanine (G) to thymine (T) bases, a transversion mutation, When applied to cultured bronchial epithelial cells, activated benzo(a)pyrene induces many mutations, including inactivating mutations of the p53 gene, at codon number______