The decline of MPF activity at the end of mitosis is due toa. the destruction of the protein kinase Cdk.b. decreased synthesis of Cdk.c. the degradation of cyclin.d. the accumulation of cyclin.

Tissue culture experiments with PDGF demonstrate that without this substance, __________.

When a cell in S phase is fused with a cell in G₁, __________.

Progression through the cell cycle is regulated by oscillations in theconcentration of which type of molecule?a. p53, Rb, and other tumor suppressorsb. receptor tyrosine kinasesc. cyclinsd. cyclin-dependent kinases

Which of the following occurs during apoptosis? (A) lysis of the cell (B) direct contact between signaling cells (C) fragmentation of the DNA (D) release of proteases outside the cell

Apoptosis involves all but which of the following?a. fragmentation of the DNAb. cell-signaling pathwaysc. lysis of the celld. digestion of cellular contents by scavenger cells

In the cells of some organisms, mitosis occurs without cytokinesis. This will result ina. cells with more than one nucleus.b. cells that are unusually small.c. cells lacking nuclei.d. cell cycles lacking an S phase.

Cytochalasin B is a chemical that disrupts microfilament formation. This chemical would interfere witha. DNA replication.b. formation of the mitotic spindle.c. cleavage.d. formation of the cell plate.