431.

α-bungarotoxin binds to acetylcholine receptor (AChR) protein with high specificity and prevents the ion-channel opening. This interaction can be exploited to purify AChR from membrane using

• Ion-exchange chromatography

• Gel filtration chromatography

• Affinity chromatography

• Density gradient centrifugation

In normal individuals, there are three MstII restriction sites, two flanking the β-globin gene and one within the gene. In individuals affected by a disease, a single nucleotide polymorphism in the β-globin gene abolishes the internal MstII recognition site. The RFLP pattern for this locus, obtained by hybridization using a probe internal to the flanking MstII sites, from three siblings of a family is shown below

Size (kb)	Normal son	Normal daughter	Affected son
1.35	-		-
1.15	-	-
0.2	-	-

Based on the above profile, what is the nature of the genetic disorder?

• X-linked recessive

• Autosomal dominant

• Autosomal recessive

• X-linked dominant

A merodiploid strain of E. coli with the genotype F⁺O^CZ^-Y⁺/O⁺Z⁺Y⁺ was constructed. The activity of the β-galactosidase enzyme was measured in this strain upon the following treatments.

(A) no induction

(B) induction with n moles of IPTG

(C) induction with n moles of lactose

(D) induction with n moles of lactose in the presence of n moles of glucose.

Which one of the following graphs depicts the expected trends in the β-galactosidase activity under the four different conditions?

In E. coli grown under nutrient-rich conditions, replication of the entire genome takes about 40 min, yet it can divide every 20 min. This is so because

• While E. coli divides every 20 min, equal transfer of genetic material occurs only in the alternate rounds of cell divisions.

• A second round of genome replication begins before the completion of first round of replication, and by the time cell is ready to divide, two copies of the genome are available.

• Genome replication and cell division are not coordinated with each other.

• During cell division, only one of the strands of the genome whose synthesis can be achieved in 20 min, is transferred to the daughter cell.

Extensive molecular genetic studies on miR156, miR172, SPLgenes and AP2-like genes have yielded the following functional model on the juvenile → adult → reproductive transition in Arabidopsis:

Based on these results, the following schematic diagram has been proposed to predict the expression kinetics of these genetic factors:

Which of the following combinations is most likely to be correct?

• a - miR156; b - SPL genes; c - miR172; d - AP2 like genes

• a - miR156; b - miR172; c - SPL genes; d - AP2 like genes

• a - miR172; b - SPL genes; c - AP2 like genes; d - miR156

• a - miR156; b - AP2 like genes; c - miR172; d - SPL genes

In a group of students, 30% play only cricket, 20% play only football and 10% play only basketball. 20% of the students play both basketball and cricket, 10% play both football and basketball. 15 students play no games, while 5% of the students play all three games. What is the total number of students?

• 300

• 250

• 350

• 400

Five persons A, B, C, D, and E are sitting in a row with C in the middle of the group. If D is at an extreme end and there at least two persons between B and E, then which of the following statements is incorrect?

• E can be on the extreme left

• E can be on extreme right

• A cannot be on extreme left

• A is always a neighbour of B or D.

A sphere G of radius b is fixed mid-air and several spheres identical to the first one are shot at it with their velocities parallel to each other. If the shot spheres fall within an imaginary cylinder of radius a (b << a) then the fraction of spheres that will hit G is

• 2b/ a

• 4b²/a²

• (a - b)/ (a + b)

• 8b³/a³

The distance from Nehrunagar to Gandhinagar is 27 km. A and B start walking from Nehrunagar towards Gandhinagar at speeds of 5 km/hr and 7 km/hr, respectively. B reaches Gandhinagar, returns immediately, and meets A at Indiranagar. What is the distance between Nehrunagar and Indiranagar? (Assume all three cities to be in one straight line)

• 12.5 km

• 22.5 km

• 4.5 km

• 15.5 km

Approximately how much blood flows per day through a normal human heart beating 70 times per minute, having a relaxed volume of 110 cc and compressed volume of 70 cc?

• 7150 litres

• 4000 litres

• 28000 litres

• 11100 litres