#Question id: 18608
#Unit 13. Methods in Biology
#Question id: 10965
#Unit 7. System Physiology – Animal
Which of the following is a TRUE statement?
#Question id: 4508
#Unit 3. Fundamental Processes
Statement: In the case of group II introns, the chemistry of splicing and the RNA intermediates produced are the same as those for nuclear pre-mRNA.
Explanations: I. The intron uses an A residue within the branch site to attack the phosphodiester bond at the boundary between its 5’ end and the end of the 5’ exon-that is, at the 5’ splice site. This reaction produces the branched lariat.
II. A second reaction in which the newly freed 3’ -OH of the exon attacks the 3’splice site, releasing the intron as a lariat and fusing the 3’ and 5’ exons.
#Question id: 12758
#Unit 10. Ecological Principles
Refer to the following experiment, which is designed to test the co evolutionary relationships among an unpalatable butterfly (the monarch), a palatable butterfly (the viceroy), and a butterfly predator (the jay). Monarch butterflies are reared on three diets: milkweed (their natural food), cabbage, and cabbage treated with an extract from milkweed leaves. Viceroy butterflies, mimics of monarchs, also are reared on three diets: willows (their natural food), cabbage, and cabbage treated with an extract from milkweed leaves. In trial 1 of the first experiment, adult butterflies reared on a particular diet are presented one at a time at 1-hour intervals to jays and the jays are allowed to feed. Each jay is fed until it refuses to eat the butterfly presented, but no more than 12 butterflies are presented to a jay during a particular test. Five birds are used for each test; therefore, up to 60 butterflies can be consumed for each diet test. The observer records the actual number of butterflies eaten. In trial 2, the experiment is repeated 2 weeks later. In the second experiment, the butterflies are reared on the same diets as in experiment 1. However, when they are offered to jays, some jays receive a monarch reared on milkweed before being offered the butterflies reared on the experimental diets; the other group of jays is first given a viceroy reared on willow before being offered the butterflies reared on the experimental diets. The initial butterfly offered is included in the total number eaten, but no more than 12 butterflies are presented to each jay.
The experimental design and the data indicate which of the following about the jays?
#Question id: 19714
#Unit 3. Fundamental Processes