Filters
Question type

Study Flashcards

Exposure of zebrafish nuclei to cytosol isolated from eggs at metaphase of mitosis resulted in phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2. NEP55 is a protein of the inner nuclear membrane, and L68 is a protein of the nuclear lamina. What is the most likely role of phosphorylation of these proteins in the process of mitosis?


A) They enable the attachment of the spindle microtubules to kinetochore regions of the centromere.
B) They are involved in chromosome condensation.
C) They are involved in the disassembly of the nuclear envelope.
D) They assist in the migration of centrosomes to opposite sides of the nucleus.

E) B) and D)
F) All of the above

Correct Answer

verifed

verified

Which of the following molecules is a protein maintained at steady levels throughout the cell cycle that requires cyclin to become catalytically active?


A) PDGF
B) MPF
C) cyclin
D) Cdk

E) All of the above
F) A) and B)

Correct Answer

verifed

verified

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?


A) The cells are unable to form spindle microtubules.
B) The cells follow an altered series of cell cycle phases.
C) The cells show characteristics of tumours.
D) The cells have nonfunctional MPF.

E) All of the above
F) A) and C)

Correct Answer

verifed

verified

Cells from advanced malignant tumours often have very abnormal chromosomes and an abnormal number of chromosomes. What might explain the association between malignant tumours and chromosomal abnormalities?


A) Cancer cells are no longer density-dependent.
B) Cancer cells are no longer anchorage-dependent.
C) Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.
D) Transformation introduces new chromosomes into cells.

E) A) and B)
F) B) and C)

Correct Answer

verifed

verified

Which of the following molecules is a protein synthesised at specific times during the cell cycle that associates with a kinase to form a catalytically active complex?


A) PDGF
B) MPF
C) cyclin
D) Cdk

E) A) and B)
F) None of the above

Correct Answer

verifed

verified

Which of the following properties is associated with a cyclin-dependent kinase (Cdk) ?


A) A Cdk is inactive, or "turned off", in the presence of a cyclin.
B) The number of Cdk molecules increases during the S and G2 phases and decrease during M.
C) A Cdk is an enzyme that catalyses the attachment of kinetochores to microtubules.
D) A Cdk is an enzyme that attaches phosphate groups to other proteins.

E) C) and D)
F) A) and C)

Correct Answer

verifed

verified

Showing 61 - 66 of 66

Related Exams

Show Answer