Following statements are regarding to Kinetochore-microtubule interaction in S. cerevisiae.

A. In the simple kinetochore of S. cerevisiae, a protein complex called CBF3 associates with specialized, centromere-specific form of histone H3, called CENP-A.

B. The Ndc80 complexes initially make lateral interactions with a spindle microtubule and subsequently interact with a Dam1 complex, which forms a ring around the end of the microtubule. This interaction results in an end-on attachment of the centromere to the

spindle microtubule.

C. Microtubules that “capture” kinetochores are selectively stabilized by a reduction in the rate of catastrophes, which increases the chance that the attachment will persist.

D. With the two kinetochores attached to opposite poles, the duplicated chromosome is now under tension, being pulled in both directions by the one sets of kinetochore microtubules.

Which of the following combinations is correct?

#Question id: 1519

#Unit 4. Cell Communication and Cell Signaling

Following statements are regarding to the FOXO3a protein.

A. In the presence of growth factors, FOXO3a is non phosphorylated and mainly localizes to the nucleus, where it activates transcription of several genes encoding pro-apoptotic proteins.

B. When growth factors are removed from the cells, PKB becomes active and phosphorylates FOXO3a.

C. Phosphorylated FOXO3a binds to cytosolic phosphoserine-binding protein 14-3-3 to bind FOXO3a and thus sequester it in the cytosol.

D. Dephosphorylated FOXO3a binds to cytosolic phosphoserine-binding protein 14-3-3 to bind FOXO3a and thus sequester it in the cytosol.

Which of the following is correct?

#Question id: 1518

#Unit 4. Cell Communication and Cell Signaling

Following statements are regarding to the some cancers harbor characteristic chromosome alterations. Chronic myelogenous leukemia (CML), a common leukemia in humans, was found to be associated with the Philadelphia chromosome.

A. Philadelphia chromosome is generated by a translocation between chromosomes 22 and 9. The two chromosomes exchange their terminal regions, which leads to a characteristic alteration in the size of chromosome 9.

B. At the breakpoint of this translocation, a new fusion protein, the BCR-ABL fusion, is generated.

C. The BCR-ABL fusion protein is a constitutively active kinase that phosphorylates multiple signal-transducing proteins.

D. If this translocation occurs in a hematopoietic cell in the bone marrow, the activity of the chimeric BCR-ABL oncogene dephosphorylate proteins thereby activating many intracellular signal-transducing proteins.

Which of the following statements are incorrect?

#Question id: 1263

#Unit 4. Cell Communication and Cell Signaling

The major classes of CAMs include

a. cadherins.    b. fibronectin.    c. Ig-superfamily CAMs.      d. P-selectins.

#Question id: 1264

#Unit 4. Cell Communication and Cell Signaling

 Desmosomes

#Question id: 1265

#Unit 4. Cell Communication and Cell Signaling

An example of an integrin containing cell junction is

#Question id: 1266

#Unit 4. Cell Communication and Cell Signaling

Integrins