Question 1

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

Accepted Answer

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. 
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.

Question 2

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?

Accepted Answer

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. 
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.

Question 3

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?

Accepted Answer

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. 
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.

Question 4

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?

Accepted Answer

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

Question 5

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?

Accepted Answer

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. 
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.

Question 6

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

Accepted Answer

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

Exam 12: The Cell Cycle

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

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?

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?

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?

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

Evolution, the Themes of Biology, and Scientific Inquiry

The Chemical Context of Life

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Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Viruses

Dna Tools and Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

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The Origin of Species

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Plant Diversity I: How Plants Colonised Land

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Basic Principles of Animal Form and Function

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