Tham khảo tài liệu 'sat ii biology episode 1 part 8', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | MOLECULAR GENETICS DNA AND EVOLUTION 9. In the illustration below the strand with an is the A promoter. B Okasaki fragment. C template. D lagging strand. 10. Darwin s Natural Selection includes all of the following EXCEPT A Variation can be due to mutations. B The difference in survivability between organisms may be due to variation. C Not all organisms may survive due to competition. D Organisms produce more offspring than can survive. E Some organisms will be more fit to survive than others. Explanation of Answers for Multiple-Choice Questions 1. The correct answer is B . In RNA thymine is replaced by uracil so the correct choice is B where DNA adenine is said to bond to an RNA thymine. All the other choices are incorrect including the DNA guanine to an RNA cytosine. The testmaker may depend on the student vaguely remembering that a certain base-pairing between DNA and RNA is not possible and may choose choice C as being correct. This is not the case. 2. The correct answer is E . Guanine is not replaced in RNA. It is found in both DNA and RNA. The trick here once again is the vague recollection of something being replaced. Of course thymine in DNA is replaced by uracil in RNA and uracil is on the list. However the question here asks about the replacement of guanine which does not occur. The bases listed in choices A and C also are found in RNA. Peterson s SAT II Success Biology E M Ũ7 CHAPTER 5 3. The correct answer is C . These recent conclusions about mutations recall that Darwin did not know of mutations are all the reverse of those listed in the choices with the exception of choice C the correct answer. Rates in fact tend to be below in populations mutations are generally not lethal any gene location can be affected and they are felt to be the source of genetic variation. Darwin felt over-production of offspring was the source of potential variation. 4. The correct answer is A . The complimentary strand for the indicated DNA strand would .
