Cell Biology: Nucleus 14163.A 29-year-old woman presents with a 101oF fever, pericardial effu-
sions and Libman-Sacks endocarditis, arthralgias, rash across the malar
region of the face (“butterfly rash”) that is accentuated by sun exposure;
creatinine is 1.7 mg/dL (normal 0.5 to 1.1 mg/dL). Laboratory tests show
high titers of antinuclear autoantibodies (ANA), Smith antigen and antinu-
cleosome antibodies in the serum. Which of the following is most likely to
be directly affected by the disruption of nucleosomes in this patient.
a. Packaging of genetic material in a condensed form
b. Transcribing DNA
c. Forming pores for bilateral nuclear-to-cytoplasmic transport
d. Forming the nuclear matrix
e. Holding together adjacent chromatids
64.A G 1 -phase and an M-phase cell are fused together with a Sendai virus.
The result is that the chromosomes in the G 1 -phase cell condense. Which
of the following would be a possible cell biological explanation?
a. Lamins will be phosphorylated in the G 1 cell
b. The S-phase activator will be expressed in the M-phase cell
c. The M-phase cell will reduplicate its DNA
d. The G 1 /S-cdk complex will be activated in the M-phase cell
e. A re-replication block will occur in the G 1 -phase cell.
65.A middle aged anatomy professor went to the hottest Indianapolis 500
race in decades and sat with the sun facing him; there was no breeze. He
had a history of borderline high uric acid. When he became dehydrated at
the race, it triggered the uric acid crystal formation in his foot. The foot
became sore, red, hot and swollen; he could not walk on that foot or even
fit into a regular pair of shoes. The race was great and he drank about 2 L
of water and soda at the race and another couple of liters when he arrived
home. Evidently that was not enough fluid because he was anuric for about
10–12 hours. His physician prescribes colchicine as an anti-inflammatory.
A metaphase-blocking dose of colchicine functions through which of the
following mechanisms?
a. Depolymerization of actin
b. Depolymerization of myosin
c. Enhancement of tubulin polymerization
d. Inhibition of tubulin polymerization
e. Binding to and stabilizing microtubules