Analytical Aptitude - Problem Set I

Analytical questions are intended to assess a student's knowledge of the subject matter emphasized in the CSIR-NET examination as preparation for doctoral study. As of 2011, the CSIR-NET committee is introducing a new pattern of examination which will contain multiple choice questions, a number of which may be grouped in sets and based on descriptions of laboratory situations, diagrams, or experimental results. Throughout the test, there will be an emphasis on questions requiring problem-solving skills (including mathematical calculations that do not require the use of a calculator) as well as content knowledge.

The CSIR-NET examination is designed to evaluate the following abilities and background of the student:

• Knowledge of basic vocabulary and facts in several life science fields at the equivalent of MSc degree
• Conceptual understanding of ideas, relationships, and processes
• Understanding of basic scientific research, procedures, and tools
• Capacity to read, evaluate, and draw conclusions from unfamiliar laboratory and field studies
• Understanding of the connections among the life science as well as between life and allied sciences
  

These problem sets (consisting of 10 sample practice questions each) will help familiarize with the type of questions in the CSIR-NET examination and cover all areas in life science. The study material in accompanying posts may be used for preparation.
----------------------------------------------------------------------------------------------------------

Problem Set I

(1) In the cross AaBb x AaBb, Mendel's principle of independent assortment predicts that the ratio of the four possible phenotypes of the offspring will be:

(a) 1 : 1 : 1 : 1

(b) 3 : 2 : 2 : 1

(c) 4 : 2 : 2 : 1

(d) 9 : 3 : 3 : 1

(e) 9 : 7 : 3 : 1

(2) If the M-phase promoting factor (MPF) is injected into a Xenopus primary oocyte, which of the following occurs?

(a) S phase begins
(b) The oocyte enters G₀
(c) Apoptosis begins
(d) The germinal vesicle (nucleus) breaks down
(e) Mitosis is completed

(3) All of the statements about the type-B cyclin proteins are correct except:

(a) their presence is required for exit from mitosis
(b) they are present in cells during the G₂ phase
(c) they are degraded via the ubiquitin pathway
(d) they inactivate Cdc2 kinase
(e) they are newly synthesized during every cell cycle

(4) In genetics, suppression of a mutation refers to:

(a) restoration of original phenotype due to a second mutation
(b) restoration of the original DNA sequence by mutation
(c) prevention of expression of the mutant gene by metabolic regulation
(d) inactivation of the gene by methylation
(e) none of the above

(5) Two-dimensional (2-D) gel electrophoresis performed under denaturing conditions can be used to separate proteins according to which of the following characteristics?

(First dimension/second dimension)

(a) subunit molecular weight/density
(b) density/charge
(c) amino acid composition/charge
(d) isoelectric point (pI)/subunit molecular weight
(e) hydrophobicity/subunit molecular weight

(6) In adult mammals, the primary site for the final stage of differentiation of T lymphocytes is the:

(a) spleen
(b) bone marrow
(c) bursa of Fabricius
(d) thymus
(e) liver

(7) The physiological role of restriction endonucleases is to:

(a) allow the in vitro construction of recombinant DNA molecules
(b) methylate host DNA
(c) remove RNA primer during DNA synthesis
(d) allow mapping of gene location
(e) cleave foreign DNA molecules that enter the cell

Questions (8) to (10) refer to the following:

Muscle cells were incubated in the presence of O₂, and then quickly made anoxic. The concentrations of various metabolites were measured immediately following the removal of O₂. The results are shown in the figure below:

(8) The change in the glucose-6-phosphate concentration can be explained best by which of the following?

(a) increased synthesis of glycogen
(b) increased conversion to free glucose
(c) increased rate of glycolysis
(d) decreased synthesis of glucose-6-phosphate
(e) acceleration of the citric acid (Krebs) cycle

(9) The initial increase in the concentration of frustose-1,6-bisphosphate is most likely due to:

(a) activation of gluconeogenesis
(b) activation of phosphofructokinase
(c) inhibition of the citric acid cycle
(d) inhibition of aldolase
(e) increase in the concentration of ATP

(10) Which of the following is most likely to happen to the concentration of lactate in the cell?

(a) it will remain the same
(b) it will increase initially and then decrease to control values as equilibrium is achieved
(c) it will increase to a new steady-state level
(d) it will decrease because the cell secretes lactate
(e) it will decrease because the cell uses lactate to synthesize glucose

Solutions will be posted on Wednesday.