Scaffolds for MAP kinase pathways are well documented in yeast, fly, and worm cells, but their presence in mammalian cells has been difficult to demonstrate. Perhaps the best documented scaffold protein in metazoans is Ksr (kinase suppressor of Ras).

A. Ksr functions as a molecular scaffold by binding several signaling components of the MAP kinase cascade, including both MEK and MAP kinase; and thus can enhance MAP kinase activation by regulating the efficiency of these interactions.

B. Ksr function as a protein kinase which constitutive activate RTK signalling pathway.

C. Ksr function as a receptor proteins which inhibits RTK signalling pathway.

D. Ksr function as a protein phosphatase which inhibits RTK signalling pathway.

Which of the following statement is correct about Ksr?

#Question id: 2992

#Unit 2. Cellular Organization

DNA was isolated from three different cell types of the same organism, the relative DNA content for each type was determined, and the results were plotted on the graph shown in the figure below. Refer to the graph to answer the following questions. Which sample of DNA might be from a cell that stopped the process of cell division in G0 phase of the cell cycle prior to meiosis?

#Question id: 2991

#Unit 2. Cellular Organization

Early observations of a cultured cell line indicated that the cells did not exhibit either density-dependent inhibition or anchorage dependence. What do these observations suggest about this cell line?

#Question id: 2990

#Unit 2. Cellular Organization

Mitotic CDK complexes are maintained in an inactive state through inhibitory phosphorylation of the CDK subunit. Two highly conserved tyrosine and threonine residues in mammalian CDKs are subject to regulated phosphorylation.

The following table enlists genes and phenotypes observed on mutation of these genes but not correctly matched. Which one of the following combinations is correctly matched ?

#Question id: 2989

#Unit 2. Cellular Organization

Use the figure to answer the question below.

In the figure, G1 is represented by which numbered part(s) of the cycle?

#Question id: 2988

#Unit 2. Cellular Organization

Use the figure to answer the question below. 

If the cell whose nuclear material is shown in the figure continues toward completion of mitosis, which of the following events would occur next?

#Question id: 2987

#Unit 2. Cellular Organization

Following statements are regarding the goals of gap phases.

(i) to prepare for the next phase of the cell cycle.

(ii) to check that the previous phase of the cell cycle has been completed appropriately.

(iii) to inhibits CDKs activity.

(iv) to enhance servillance mechanisms.

Which of the following is correct?