MOD 10

Which of the following is not a cell cycle checkpoint? a. G2 arrest to check for proper spindle formation. b. G2 arrest to check for DNA damage. c. S-phase arrest to check for unreplicated DNA. d. G1 arrest to check for DNA damage.

a.

As a cell enters mitosis the now active MPF mediates phosphorylation of many of the key proteins required for progression through prophase. What are the targets of MPF phosphorylation involved in endomembrane fragmentation? a. cohesins b. GM130 c. microtubule associated proteins d. lamins

b.

As a cell enters mitosis the now active MPF mediates phosphorylation of many of the key proteins required for progression through prophase. What are the targets of MPF phosphorylation involved in preparation of sister chromatids for separation? a. condensins and histones b. cohesins c. microtubule associated proteins d. lamins

b.

Which of the following statements about mitogens is not true? a. They are growth factors that induce G1 in a resting cell. b. They induce phosphorylation of the transcription factor c-fos. c. They are required until the cell passes the Restriction Point. d. They regulate phosphorylation of transcription factors by MAP kinase.

b.

Which of the following statements is not true regarding the breakdown of the nuclear envelope? a. Before condensation, chromatin is associated with lamins at the nuclear membrane. b. phosphorylation results in lamin A and B being dispersed into the cytosol c. Lamins exist as tetramers that dissociate into dimers on phosphorylation. d. Lamin B remains associated with the membrane during NEB.

b.

Which of the following statements are true about nucleosomes and histones? More than one answer may be correct. a. The histone core is an octamer of H1, H2a, H2b and H3. b. H1 is the histone linker between nucleosomes. c. H1 and H3 are phosphorylated for mitosis to proceed. d. H1 and H3 form a dimer when phosphorylated. e. DNA is unwound from the histones during condensation. f. H2a and b and H4 are phosphorylated for mitosis to proceed.

b., c.

c-fos is an example of an early gene. Which of the following statements is true about c-fos? a. It is a transcription factor that activates the early response genes. b. In resonse to a mitogen it does not need to be translated, just phosphorylated. c. It is a transcription factor that transcribes the delayed response genes. d. It is activated by the delayed response genes.

c.

Which of the following is not an event of telophase? a. ER reassembles b. chromosome decondensation c. nuclear envelope reforms d. activation of MPF

d.

Which statement is not true about the Restriction Point? a. It occurs in G1 before S-phase. b. It signifies commitment by the cell to proceed through the cell cycle. c. If mitogen is removed after the Restriction Point cells will divide. d. If mitogen is removed before the Restriction Point is reached cells will divide.

d.