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? 

#Question id: 880

#Part-A Aptitude & General Biotechnology

The classic work of Christian Anfinsen in the 1950s on the enzyme ribonuclease revealed the relation between the amino acid sequence of a protein and its conformation. Ribonuclease is a single polypeptide chain consisting of 124 amino acid residues cross-linked by four disulfide bonds. Anfinsen’s plan was to destroy the three-dimensional structure of the enzyme and to then determine what conditions were required to restore the structure.

The critical observation of Anfinsen that the denatured ribonuclease, freed of urea and b -mercaptoethanol by dialysis;

I. The sulfhydryl groups of the denatured enzyme became reduced by air, and the enzyme spontaneously refolded into a catalytically active form.

II. These experiments showed that the information needed to specify the catalytically active structure of ribonuclease is contained in its amino acid sequence.

III. The 105 wrong pairings have been picturesquely termed “scrambled” ribonuclease.

IV. He found that scrambled ribonuclease spontaneously converted into fully active, native ribonuclease when trace amounts of b -mercaptoethanol were added to an aqueous solution of the protein.

Choose incorrect options;

#Question id: 881

#Part-B Specialized Branches in Biotechnology

 ______and ________ are the first chaperones a newly made prokaryotic protein encounters. Subsequently, many partially folded proteins are handed off to other chaperones to complete the folding process. E. coli can tolerate the elimination of_______ or________, but not both, thereby indicating that they are functionally redundant.

#Question id: 882

#Part-B Specialized Branches in Biotechnology

Choose correct statements about thermophilic proteins

I. The proteins found in thermophilic species are much more stable than their mesophilic counterparts.

II. All thermostable proteins have such a high incidence of salt bridges

III. the most important of which are an increased size of the protein’s hydrophobic core, an increased size of the interface between its domains and/or subunits, and a more tightly packed core as evidenced by a reduced surface-to-volume ratio.

IV. Several of these thermostable enzymes have a superabundance of salt bridges on their surfaces.

#Question id: 882

#Part-A Aptitude & General Biotechnology

Choose correct statements about thermophilic proteins

I. The proteins found in thermophilic species are much more stable than their mesophilic counterparts.

II. All thermostable proteins have such a high incidence of salt bridges

III. the most important of which are an increased size of the protein’s hydrophobic core, an increased size of the interface between its domains and/or subunits, and a more tightly packed core as evidenced by a reduced surface-to-volume ratio.

IV. Several of these thermostable enzymes have a superabundance of salt bridges on their surfaces.

#Question id: 887

#Part-B Specialized Branches in Biotechnology

Polypeptides fold rapidly by a stepwise process, how does the polypeptide chain arrive at its native conformation?

#Question id: 887

#Part-A Aptitude & General Biotechnology

Polypeptides fold rapidly by a stepwise process, how does the polypeptide chain arrive at its native conformation?