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TLS Online TPP Program

#Question id: 12960

The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years.

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.

Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.
Which of the following is most likely correct concerning the gene for resistance to warfarin? 

#Unit 10. Ecological Principles
  1. It is a wild-type gene induced to mutate by the direct action of warfarin.
  2. It is a mutation subsequently favoured by natural selection. 
  3. It is increased in frequency by virtue of its dominant status.
  4. It is carried by a bacterial plasmid vector.
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TLS Online TPP Program

#Question id: 24493

#Unit 3. Fundamental Processes

Splice sites are directional in nature. 5’ splice site -the left, or donor, site and the 3’ splice site - right, or acceptor, site. 
1. U2 addition to base pair with the branch site in the presence of ATP
2. U1 and U4 release Formation of the catalytic center in which U6 base pairs with the 5' splice site; U6 also base pairs with U2; U2 remains base paired with the branch site; U5 interacts with both exons through its loop.

So, 1 and 2 are the event of complex formation which are 
TLS Online TPP Program

#Question id: 24494

#Unit 3. Fundamental Processes

U1 and U4 release Formation of the catalytic center in which U6 base pairs with the 5' splice site; U6 also base pairs with U2; U2 remains base paired with the branch site; U5 interacts with both exons through its loop is the characterstic of one of the stage during splicing, which is 
TLS Online TPP Program

#Question id: 24495

#Unit 3. Fundamental Processes

Which of the following step of splicing involves ATP
TLS Online TPP Program

#Question id: 24496

#Unit 3. Fundamental Processes

Lariat formation is characterized by
TLS Online TPP Program

#Question id: 24497

#Unit 3. Fundamental Processes

Choose the incorrect statement 
A. Lariat formation is characterized by 2’-5’ phosphodiester bond
B. Lariat formation is characterized by 3’-5’ phosphodiester bond
C. Group II mitochondrial introns are excised by the same mechanism as nuclear pre-mRNAs via a lariat that is held together by a 2’–5’ bond.
D. Group II mitochondrial introns are excised by the different  mechanism as nuclear pre-mRNAs via a lariat that is held together by a 2’–5’ bond.
TLS Online TPP Program

#Question id: 24498

#Unit 3. Fundamental Processes

SR proteins are involved in exon definition in which they interact with U1 and U2AF forming the commitment for