A NASA probe returned samples of rocks from the surface of Mars. From these rocks, a prokaryotic organism was isolated and remained viable under conditions similar to those of Mars
The organisms are capable of dividing to replicate themselves. In order to determine whether the DNA replication of these organisms was semiconservative, an experiment using N15/N14 (similar to that of Meselson and Stahl) was performed. If the method of DNA replication were conservative, after one generation one would expect to see
A) all of the DNA in the heavy (N15) band.
B) all of the DNA in the light (N14) band.
C) all of the DNA at a point midway between the heavy and light bands.
D) half of the DNA in the light band, the other half in the heavy band.
E) None of these are correct.
Answer: D
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A diet of primarily grains would likely be deficient in the____ fatty acids
a. linoleic and phospholipid
b. linoleic and linolenic c. omega-5 and omega-3 d. linolenic and omega-5 e. phospholipid and omega-3
A newly evolved species may take over an ecological role or ecological niche that is already occupied
if the new species has:a. the ability to alter or change the environmental parameters. b. features that make it competitively superior to the original occupant of that niche. c. the ability to evolve through natural selection, whereas the original occupant cannot continue to evolve. d. the ability to grow to a larger size, thus providing it with a selective advantage. e. fitness that is almost as high as the fitness of the original species.
Which one of the following is TRUE regarding nucleotides?
A) There are three different DNA nucleotides. B) DNA nucleotides are assembled into RNA by the process of dehydration synthesis. C) DNA nucleotides contain deoxyribose; RNA nucleotides contain sucrose. D) Nucleotides are bonded together by covalent bonds between the sugars and the phosphates. E) A DNA nucleotide could be made up of ribose, a phosphate, and cytosine.
If a cell had 12 chromosomes at the beginning of meiosis II, how many would each daughter cell have after the completion of meiosis II?
A) 6 B) 12 C) 18 D) 24