#Question id: 1524
#Unit 4. Cell Communication and Cell Signaling
Tumor-suppressor genes generally encode proteins that in one way or another inhibit cell proliferation. Loss-of-function mutations in one or more of these proliferation inhibitory proteins contribute to the development of many cancers. Prominent among the classes of proteins encoded by tumor-suppressor genes are:
A. Intracellular proteins that regulate or inhibit entry into the cell cycle
B. Receptors or signal transducers for secreted hormones or developmental signals that inhibit cell proliferation
C. Checkpoint pathway proteins that arrest the cell cycle if DNA is damaged
D. Proteins that promote apoptosis
Following genes belongs to the above class-
i. p53
ii. Rb
iii.TGF- β
iv. Caspase 3 and 7
which of the following match is correct?
#Question id: 1525
#Unit 4. Cell Communication and Cell Signaling
Following statements are regarding to chromatin remodelling factors SWI/SNF complexes. Which one of them is incorrect?
#Question id: 1526
#Unit 4. Cell Communication and Cell Signaling
Following statements are regarding to apoptosis.
A. In the worm apoptotic pathway, CED-3 (caspase-9 in mammals) is a protease required to destroy cell components during apoptosis.
B. CED-4 (Apaf-1) was able to accelerate the autoproteolytic cleavage and activation of purified CED-9
C. Once EGL-1 causes dissociation of the CED-4/CED-9 complex, the released CED-4 dimer joins with three other CED-4 dimers to make an octamer, which then activates CED-3
D. Many apoptotic stimuli lead to damage of the outer mitochondrial membrane, causing release into the cytosol of several proteins that stimulate apoptosis. In particular, cytochrome c released from mitochondria activates Apaf-1, which in turn activates caspase-3 and 7.
Which of the following combination is incorrect?
#Question id: 1527
#Unit 4. Cell Communication and Cell Signaling
Following are the six fundamental properties of malignant tumors. Which of these properties are amenable to study in a cell culture model of cancer?
(I) self-sufficiency in growth signals
(II) insensitivity to antigrowth signals
(III) evasion of apoptosis
(IV) limitless replicative potential
(V) sustained angiogenesis
(VI) tissue invasion and metastasis
#Question id: 1528
#Unit 4. Cell Communication and Cell Signaling
Mutation of p53 is described as a dominant-negative mutation. Which of the following statement is correct regarding to the mechanism by which this mutation causes the dominant-negative phenotype?
#Question id: 1529
#Unit 4. Cell Communication and Cell Signaling
Which of the following statements are true regarding to gain-of-function and loss-of-function mutations with respect to cancer.