Both PHYA and PHYB activate the transcription of LHCB gene for its expression, there following events occur during the activation of LHCB gene such as;

a) PhyA, both form is activated Pr and Pfr by phosphorylation Pr form move into the nucleus activate the light-regulated gene expression during degradation of  the HY5 by COP1

b) PhyA, Pfr form is activated by phosphorylation and move into the nucleus where it’s export the COP1 out of the nucleus, and activate the light-regulated gene expression

c) Phy B, activated phosphorylated Pfr form is move into the nucleus and binds to a dimer of the transcription factor PIF3, by inibiting PIF3 expression activate the transcription of LHCB gene by intermediate transcriptional factor MYB

d) Phy B, activated unphosphorylated Pfr form is move into the nucleus and binds to a monomer of the transcription factor PIF3, by inibiting PIF3 expression activate the transcription of MYB gene by intermediate transcriptional factor LHCB

Which of the following combination of the above statements of phytochrome forms is correct?

#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?

#Question id: 1532

#Unit 4. Cell Communication and Cell Signaling

For a particular microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. Which of the following types of evidence will researchers be looking for in order to determine if the cells are cancerous?

#Question id: 1533

#Unit 4. Cell Communication and Cell Signaling

Why might using retroviral vectors for gene therapy increase the patient's risk of developing cancer?