Practice Questions

  1. Home
  2. Free Resources
  3. Practice Questions
  4. 55068
TLS Online TPP Program

#Question id: 12182

The cell cycle is controlled by protein kinases that comprise a catalytic subunit and a regulatory subunit. Which of the following statement is correct regarding to these subunits?

#Unit 2. Cellular Organization
  1. The catalytic subunits, the cyclin-dependent kinases (CDKs), have no kinase activity unless they are dissociated with a regulatory cyclin subunit. 
  2. Each CDK can associate with a small number of different cyclins, which determine the substrate specificity of the complex—that is, which proteins it phosphorylates.
  3. Cyclin-CDK complexes activate or inhibit hundreds of proteins involved in cell cycle progression by phosphorylating or dephosphorylating them at specific regulatory sites. 
  4. Proper progression through the cell cycle is governed by activation of the appropriate homodimeric protein kinase complex at the appropriate time.
More Questions
TLS Online TPP Program

#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?
TLS Online TPP Program

#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.
TLS Online TPP Program

#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?
TLS Online TPP Program

#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
TLS Online TPP Program

#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?
TLS Online TPP Program

#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?