Which of the following is true about telomeres and immortality?
A. Immortal cell lines lack telomeres.
B. Immortal cell lines lack telomerase.
C. Reactivation of telomerase in humans will cause them to become immortal.
D. Tumor cell lines can be immortal if their telomerase gene is reactivated.
E. Immortal cell lines have telomerase activity but cannot form t-loops and don't have protective proteins to prevent recombination repair.
D
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All of the following statements about cellulose are true EXCEPT:
A. Cellulose is composed of fibers of carbohydrates. B. Cellulose is an important source of plant fiber for our diet. C. Cellulose is the primary molecule found in wood. D. Cellulose is one of the most abundant organic molecules on Earth. E. Certain animals like ourselves can easily digest cellulose and use it as a source of energy.
NADH concentrations serve to regulate oxidative decarboxylation and the TCA cycle. Which of the following enzymes is not regulated by NADH?
A) pyruvate dehydrogenase B) isocitrate dehydrogenase C) ?-ketoglutarate dehydrogenase D) malate dehydrogenase E) succinate dehydrogenase
Blood from the systemic circuit is first received by the heart in the
a. coronary vein. b. left atrium. c. right ventricle. d. right atrium. e. left ventricle.
All the following are true of companion cells EXCEPT that they
A) cooperate with sieve-tube elements in conducting sugar-rich solutions. B) are connected to sieve-tube elements via plasmodesmata. C) supply materials to repair the plasma membrane of sieve-tube elements. D) provide proteins and ATP to sieve-tube elements. E) fuse together to form the sieve plates of sieve-tube elements.