Ras is a GTP-binding protein that is often defective in cancer cells. A common mutation found in cancer cells causes Ras to behave as though it were bound to GTP all the time, which will cause cells to divide inappropriately
From this description, the normal Ras gene is _______.
(a) a tumor suppressor.
(b) an oncogene.
(c) a proto-oncogene.
(d) a gain-of-function mutation.
Choice(c) is correct. Only the mutated form of Ras is an oncogene [choice (b)] and a gain-of-function mutation [choice (d)].
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Refer to the paragraph on the Venter et al. paper and the table above. Because DNAs for sequencing were chosen at random with no way of knowing which organism they came from, how could genes be identified?
A) by searching for open reading frames (ORFs), especially those with translation start and stop sites B) by searching for similarity between predicted ORFs and those in existing databases C) by searching for exons bounded by consensus donor and acceptor splice sites (those that mark exon/intron boundaries) D) by searching for ORFs, particularly those with translation start and stop sites, as well as for similarity between predicted ORFs and those in existing databases
Effector molecules
A) are associated with the induction of enzyme synthesis. B) are associated with the repression of enzyme synthesis. C) induce conformational changes. D) are often small organic molecules. E) all of the above
If a compost pile is turned frequently and other conditions are adequate for aerobic digestion, the composting can be completed in 6 weeks
Indicate whether this statement is TRUE or FALSE.
A human white blood cell engulfs a bacterial cell by:
a. carrier-mediated facilitated diffusion. b. exocytosis. c. phagocytosis. d. pinocytosis. e. the sodium-potassium