The accompanying figure depicts the map of a part of E. coli genome harboring the lac operon.

 lac mRNA would hybridize to which of the following DNA?

1) lac I; 2) lac 0; 3) lac Z; 4) lac Y; 5) lac A

#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.

#Question id: 1530

#Unit 4. Cell Communication and Cell Signaling

What are the differences and similarities between the transforming genes of retroviruses and those of DNA tumor viruses?