What part of the cell cycle does the pRB protein help to regulate?

a) the G0 - G1 transition
b) the G2 - M transition
c) the S - G2 transition
d) the G1 - S transition


Ans: d) the G1 - S transition

Biology & Microbiology

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Although especially useful to the giraffe, the rete mirabile is similar to a countercurrent heat exchange system in other related, less evolved, mammals. Thus a mechanism for _________________ homeostasis is likely to have evolved from a mechanism previously used for __________________ homeostasis.  

A.  blood pressure; pH B.  temperature; blood pressure C.  blood pressure; temperature D.  pH; blood pressure Adult giraffes can be up to 20 ft. tall, and thus require special adaptations to maintain appropriate blood pressure. One adaptation is the rete mirabile, a group of blood vessels that form a web or net-like structure to slow blood flow.

Biology & Microbiology

Which of the following is NOT true about

cyanobacteria? a. Cyanobacteria have the same light-capturing chlorophylls as plants. b. Chloroplasts evolved from ancient cyanobacteria. c. Cyanobacteria can fix carbon. d. Cyanobacteria can fix nitrogen. e. Cyanobacteria put nearly all of the nitrogen into Earth’s atmosphere.

Biology & Microbiology

Which of the following is the cancer of epithelial cells?

A. carcinoma B. leukemia C. lymphoma D. myoloma E. sarcoma

Biology & Microbiology

Marine biologists tagged and released 50 marlin. Later, fishermen caught 300 marlin, 15 of which had

tags. What is the estimate for the number of marlin in the population?

a. 5,000 b. 315 c. 365 d. 2,500 e. 1,000

Biology & Microbiology