GATE life science sample paper

Q.1 In corn there are 10 chromosomes per set and the species is diploid. A karyotype was performed from the endosperm cells grown in tissue culture in a medium containing colchicine. What is the total number of chromosomes in an endosperm cell after the first round of cell divisions?

(a) 5

(b) 14

(c) 15

(d) 30

Q.2 Three of the four eukaryotic rRNAs are synthesized from a single transcription unit consisting of the rDNA. Which one of the following does NOT belong to this group?

(a) 5.8S

(b) 5S

(c) 18S

(d) 28S

Q.3 When ß-[³² P]-ATP is incubated in an eukaryotic cell extract that is capable of transcription and RNA processing where does the label appear in the m-RNA?

(a) Every phosphate group of the m RNA is labelled

(b) Only the 5-end of the m RNA is labelled provided the first base is A

(c) Only the 3-end of the m-RNA is labelled provided the last base is A

(d) The label does not appear at all in m-RNA

Q.4 Which particle converts cholesterol to cholesterol esters?

(a) LDL

(b) Chylomicrons

(c) VLDL

(d) HDL

Q.5 A patient presents with lethargy and a 10-fold increase in plasma ammonia and glutamine levels due to a defect in the urea cycle. The build-up of what other metabolite in the plasma is consistent with a defect in ornithine transcarbamoylase and not carbamoyl phosphate synthetase I?

(a) Urea

(b) Arginine

(c) Ornithine

(d) Citrulline

Q.6 Tay-Sachs Disease, characterized by intralysosomal accumulation of the GM2 ganglioside, results from a deficiency in

(a) Sphingomyelinase.

(b) Galactocerebrosidase.

(c) Glucocerebrosidase.

(d) Hexosaminidase A.

Q.7 Which of the following assays is currently being used for the detection of Helicobacter pylori?

(a) Agglutination

(b) Complement fixation

(c) Enzyme-linked immunosorbent assay

(d) Immunodiffusion

Q.8 An individual was found to be heterolo-gous for IgG₁ allotypes 3 and 12. The different possible IgG₁ antibodies produced by this individual will never have

(a) Two H chains of allotype 12

(b) Two L chains of either Κ or Λ

(c) Two H chains of allotype 3

(d) Two H chains, one of allotype 3 and one of allotype 12

Q.9 The resting membrane potential

(a) Occurs only in nerve and muscle cells

(b) Is the same in all cells.

(c) Is oriented so that the cell's interior is positive with respect to the extracellular fluid.

(d) Requires the separation of most of the cell's charged particles.

Q.10 Which of the following is NOT part of Koch's postulates?

(a) The microorganism is never found in healthy animals.

(b) The microorganisms is always found in diseased animals.

(c) The microorganism must cause disease in healthy animals.

(d) The microorganism must secrete a toxin in culture.