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

Which of the following supports the hypothesis that viceroys receive protection from predation because they resemble monarchs?

#Question id: 4115

#Unit 3. Fundamental Processes

The possible type of splicing outcome of given gene construct will be

#Question id: 4114

#Unit 3. Fundamental Processes

Splice-site recognition is prone to two kinds of errors. First, splice sites can be skipped, with components bound at, for example, a given 5’ splice site pairing with those at a 3’ site beyond the correct one. Ways in which the accuracy of splice-site selection can be enhanced are as

A. The factors that recognize that site are transferred from the polymerase carboxy-terminal “tail” onto the RNA. Once in place, the 5’ splice site components are poised to interact with those other factors that bind to the next 3’ splice site to be synthesized.

B. SR (serine–arginine-rich) proteins bind to sequences called exonic splicing enhancers (ESEs) within the exons. SR proteins bound to these sites recruit the splicing machinery to the nearby splice sites to ensure correct splicing

C. By recruiting splicing factors to each side of a given exon, this process encourages the so-called “exon definition, contribute to correct splicing

D. Alternative splicing is intentional missplicing mechanism

Which of the following is INCORRECT?

#Question id: 4113

#Unit 3. Fundamental Processes

Match the transcriptional machinery with their respective RNA Polymerase

#Question id: 4112

#Unit 3. Fundamental Processes

Which of the following is the structure of the nucleotide at the branch site of a spliced intron?

#Question id: 4111

#Unit 3. Fundamental Processes

Which of the following is NOT characteristic of a eukaryotic enhancer element?

#Question id: 4110

#Unit 3. Fundamental Processes

Tay-Sachs disease belongs to the family of lysosomal storage diseases; it is an autosomal recessive neurodegenerative disorder caused by deficiency of the lysosomal enzyme hexosaminidase. The inability to degrade sphingolipids results in the deposition of these lipids in the cells that causes severe mental retardation and death in childhood. The most common mutation in Tay-Sachs disease patients is a 4-base pair insertion in exon 11 of the 14 exons of the hexosaminidase gene. What could be the most likely consequence of this mutation?