GATE 2004 PAPER

BIOCHEMISTRY

Q.1 – 10 carry one mark each

1. The most abundant atom in living organism is

(A) Hydrogen

(B) Oxygen

(C) Nitrogen

(D) Carbon

2. The coenzyme involved in transfer of carboxyl group is

(A) NADH

(B) Coenzyme A

(C) S- Adenosyl methionine

(D) Biotin

3. The unit of length Angstrom equals to

(A) 10^-6 m

(B) 10^-8 m

(C) 10^-10 m

(D) 10^-15 m

4. Which of the following triplet does NOT code for any amino acid

(A) UUA

(B) UCA

(C) UAA

(D) UGU

5. Erythrocytes resist shearing forces while traveling through narrow blood vessels because they contain the meshwork of

(A) Glycophorin A

(B) Spectrin

(C) Hemoglobin

(D) Myogobin

6. Tetrodotoxin, a highly poisonous toxin from Puffer fish acts on

(A) Sodium Channel

(B) Potassium Channel

(C) Chloride Channel

(D) Calcium Channel

7. Electron flow in Cytochrome oxidase in the respiratory chain can be blocked by

(A) Rotenone

(B) Amytal

(C) Cyanide

(D) Cycloheximide

8. in case of humans, passive immunity observed in newborn child is due to the passage of the following immunoglobulin from the mother to the child through placenta

(A) IgD

(B) IgE

(C) IgM

(D) IgG

9. In eukaryotic cell, around 5% cytosine residues are methylated, the methylation most commonly occurs in the following sequence

(A) CpA

(B) CpT

(C) CpG

(D) CpC

10. the following reagent will NOT releases the integral proteins from the plasma membrane

(A) Sodium chloride

(B) Triton X – 100

(C) Sodium dodecyl sulphate

(D) NP – 40

Q.11 – 30 carry two marks each

11. The biochemical reactions leading from glucose to the generation of glyceraldehyde – 3 – phosphate consume ATP. The number of ATP molecules consumed for the conversion of one molecule of glucose to glyceraldehyde – 3 – phosphate is

(A) 2 (B) 1 (C) 3 (D) 4

12. Monoclonal antibodies were raised against three different proteins containing unique epitopes. All the monoclonal antibodies were mixed together and placed in one of the wells in an Ouchterlony Double Diffusion plate. Similarly all three proteins were mixed together and placed in the adjacent well. The number of precipitin bands observed after incubation are

(A) 3 (B) 2 (C) 1 (D) 0

13. L – 19 RNA from the protozoan Tetrahymena was demonstrated to have two enzymatic activities and these activities are

(A) RNA polymerase, DNA polymerase

(B) Ribonuclease, RNA polymerase

(C) Ribonuclease, Deoxyribonuclease

(D) Ribonuclease, Protease

14. A single standard DNA of unknown size can NOT be distinguished from a double stranded DNA by

(A) Analysis of base composition

(B) Thermal denaturation

(C) Density gradient ultracentrifugation

(D) Gel Electrophoresis

15. Telomerase is an enzyme whose macromolecular composition is

(A) Lipoprotein only (B) Ribonucleoprotein only

(C) Ribonucleic acid only (D) Protein only

16. The molecular weight of IgG – Antigen complex at antigen excess is 300kd. The molecular weight of antigen is

(A) 75 (B) 50 (C) 100 (D) 150

17. The net reaction of the Citric acid cycle is

(A) Acetyl CoA+2NAD⁺+FAD+GDP+Pi+2H₂O à

2CO₂+2NADH+FADH₂+GTP+2H⁺+CoA

(B) Acetyl CoA+3NAD⁺+FAD+GDP+Pi+2H₂O à

2CO₂+3NADH+FADH₂+GTP+2H⁺+CoA

(C) Acetyl CoA+2NAD⁺+2FAD+2GDP+2Pi+2H₂O à

2CO₂+2NADH+2FADH₂+2GTP+CoA

(D) Acetyl CoA+NAD⁺+FAD+GDP+Pi+H₂O à

2CO₂+NADH+FADH₂+GTP+CoA

18. Genetic variation between individuals within a species involving different alleles at a locus is called

(A) Isotypic variation (B) Idiotypic variation

(C) Allotypic variation (D) Haplotypic variation

19. A pentameric IgM molecule was electrophoresed on a reducing SDS –Polyacrylamide gel. How many bands one can expect

(A) 1 (B) 2 (C) 3 (D) 4

20. Viral encoded ras oncogene transforms normal mammalian cells into cancer cells. Vira Ras protein differs from its normal counterpart by

(A) Diminished GTPase activity

(B) Increased GTPase activity

(C) Diminished ATPase activity

(D) Increased ATPase activity

21. choose the correct match

Group I Group II

P Immunodeficiency disease Hexosaminidase - A

Q Tay-Sach disease Hypoxantine –guanine

phosphoribosyl - transferse

R Lesh-Nyhan syndrome Chloride channel

S Cystic fibrosis Adenosine deaminase

(A) P-1 Q-3 R-4 S-2

(B) P-3 Q-2 R-4 S-1

(C) P-4 Q-1 R-2 S-3

(D) P-2 Q-4 R-3 S-1

22. Choose the correct match

Group I Group II

P b-ketoacyl-ACP synthase 1 reduces double bond forming saturated acyl-ACP

Q b-ketoacyl-ACP reductase reduces b-keto group to b-hydroxy group

R Enoyl-ACP-reductase Condenses acyl and malonyl groups

S Acyl carrier protein (ACP) Carries acyl group in thioester linkages

(A) P-2 Q-1 R-3 S-4

(B) P-3 Q-2 R-1 S-4

(C) P-4 Q-1 R-2 S-3

(D) P-3 Q-1 R-2 S-4

23. a DNA was labeled at its 5` end using g ³² P-ATP. Choose the correct combination from the following options to separate te free g ³² P-ATP from g ³² P labeled DNA

P g ³² P-ATP can be removed by treating the sample with phosphatases

Q the labeled samples can be eletrophoresed and blotted onto nitrocellulose membrane and then labeled DNA can be removed from nitrocellulose membrane

R Sample can be passed through a gel filtration coloumn to separate free g ³² P-ATP

S DNA can be precipitated using ethanol to separate it from contaminating g ³² P-ATP,

(A) P,Q

(B) P,S

(C) R,S

(D) R,Q

24. A team of researchers had used the following eluting buffers to prepare an anti albumin IgG from an anti IgG affinity column,

Buffer A: 0.1 M Glycine-HCl, pH3.0

Buffer B: 0.1 M Sodium acetate, pH 6

Buffer C: 0.1 M Sodium phosphate, pH 7

Buffer D: 0.1 M Tris HCl, pH 8

Which of the above buffers can be used for antialbumin IgG elution?

(A) Buffer A

(B) Buffer B

(C) Buffer C

(D) Buffer D

25. Oligosaccharide chain is added to the Aspagine residue of a newly synthesized protein on the luminal side of the endoplasmic reticulum membrane. The Aspargine of the newly synthesized protein that is linked to oligosaccharide chain is a part of the sequence (x, can be any amino acid other than praline)

(A) Asn-x-Asp

(B) Asn-x-Thr

(C) Asn-x-Ile

(D) Asn-x-Gly

26. the signal recognition particle binds to the signal peptide of the protein undergoing, synthesis resulting into a pause in the translational process. The pause in the translational phenomenon is due to

(A) Inactivation of aminoacyl-tRNa syntheses

(B) Inhibits the activity of elongation factor Tu

(C) Induced conformational change in the smaller ribosomal subunit

(D) Blockade of the entry of the next aminoacyl-tRNA for the reaction

27. Which of the following statement is NOT true with respect to the Photosystem II found in the chloroplasts? (Photosystem I = PS I, Photosystem II = PS II)

(A) PS II is located in the grana

(B) Chlorophyll molecule in the reaction center for the PS II is bound to a 110Kd integral membrane protein

(C) a complex of Cytochrome b and f transports electrons from PS II to PS I

(D) PS II reaction canter is bound to two Mn²⁺ ions

28. Choose the statement that is NOT correct with respect to the protein kinase (PKC)

(A) Activated PKC can phosphorylate the specific tryptophan residue on the target protein

(B) PKC is a Ca²⁺dependent kinase

(C) PKS can be activated by diacylglycerol

(D) Activation of PKC can lead to the activation of MAP kinase

29. ‘Enhancer’ elements are known to increase the rate of transcription when present at the upstream side of the promoter sequences. If the same enhancer element is placed in reverse orientation,

(A) The rate of transcription increases

(B) The rate of transcription decreases

(C) The rate of transcription remains same

(D) No transcription is observed

30. Choose the group containing only the peptide hormones

(A) Vasopressin, Oxytocin, Epinephrine

(B) Vasopressin, Testrosterone, Glucagon

(C) Oxytocin, Vasopressin, Somatostatin

(D) Oxytocin, Vasopressin, Somatostatin

Solutions

1. (D 2. (D) 3. (C) 4. (C) 5. (B) 6. (A)

7. (C) 8. (D) 9. (C) 10. (A) 11. (A) 12. (D)

13. (B) 14. (D) 15. (B) 16. (A) 17. (B) 18. (C)

19. (A) 20. (A) 21. (C) 22. (B) 23. (C) 24. (D)

25. (B) 26. (B) 27. (B) 28. (A) 29. (C) 30. (D)

CHEMISTRY

[Useful data: Gas constant, R = 8.3143 J K^-1 mol^-1 ; Faraday = 96500 C mol^-1]

Q.1 – 10 carry one mark each

1. For a second order reaction, 2B à Products, if the initial concentration of the species B is[B]_o and the rate constant is k, the t_1/2 can be expressed as:

(A) 1/[B]₀ k

(B) 1/k

(C) [B]₀ / k

(D) ½ [B]_o k

2. If the heats of reaction of the following transformation C + 0₂ (g) à CO₂ (g) are Q, 11.5 and 10.5 joules respectively, then Q in joules is equal to:

(A) 120.75

(B) 1

(C) -1

(D) 22

3. The spontaneity of a reaction can be judged from the sign of the emf (E) and the free energy (G) of the cell. The criteria are:

(A) DG = +ve, E = -ve

(B) DG = 0, E = 0

(C) DG = -ve, E = +ve

(D) DG = -ve, E = -ve

4. The function Cos(ax) is an eigen function of d²/dx² with an eigen value of:

(A) -a

(B) –a2

(C) a

(D) –a-2

5. The heteronuclear diatomic molecule that is isoelectronic to HCN is:

(A) NO

(B) CO

(C) BO

(D) SO

6. The bond order in Be₂ molecule can be expected to be:

(A) 0

(B) 1

(C) 2

(D) 3

7. The intense color of KMnO₄ is due to:

(A) Electronic transition from one energy level to another in Mn

(B) Electronic transition from one energy level to another in O

(C) Charge transfer from Mn to O

(D) Charge transfer from O to Mn

8. Of the following, the compounds that are aromatic are:

(A) 1,4

(B) 1,2,4

(C) 2,3,4

(D) 2,4

9. The hybridization of the atom indicated by an asterisk in the following compounds in a sequence (from 1 to 4) is given by:

(A) sp³, sp², sp³, sp

(B) sp², sp², sp³, sp²

(C) sp², sp², sp³, sp

(D) sp², sp³, sp³, sp

10. Which of the following compounds can have enantiomers?

(A) 2,3,4

(B) 1,3,4

(C) 3,4

(D) 1,3

Q.11 – 30 carry two marks each

11. The rate constant for a certain reaction is found to be doubled when the temperature is raised from 27 to 37°C. The activation energy for this reaction in KJ is:

(A) 26.8 (B) 107.2 (C) 53.6 (D) 50.0

12. The standard potential for the electrodes Hg½Hg₂⁺² and Hg½Hg⁺² are -0.799 and -0.855 volts at 25°C, respectively. The equilibrium constant for the reaction

Hg + Hg⁺² D Hg₂⁺² is:

(A) 85.12 (B) 79.12 (C) 70 (D) 90.20

13. The freezing point of pure benzene is 5.44°C and that of a solution containing 2.092g of A in 100g of benzene is 4.44°C. The molal depression constant (k_f) for benzene is 5.1. From this data, the molecular weight of A can be calculated to be:

(A) 106.7 (B)206.6 (C)213.4 (D) 53.2

14. The ion conductance of the alkali metal cations at given concentration follow the following order:

(A) Li⁺>Na⁺>K⁺>Rb⁺

(B) Li⁺⁺⁺>Rb⁺

(C) Li⁺⁺⁺⁺

(D) Li⁺@Na⁺>K⁺>Rb⁺

15. A system undergoes a certain change in state by path I. The heat absorbed and the work done for this process are 10 kcal mol^–1 and 0 ergs mol^–1, respectively. The respective quantities for the same change in state by path II are 11kcal mol^–1 and 0.5 w_max, where w_max is the work done if the change were reversibly carried out. The magnitude of w_max in kJ mol^–1(1 cal = 4.2J) is:

(A) 4.2 (B) 2 (C) 1 (D) 8.4

16. The total pressure for the reaction C(s) + CO₂(g) D 2CO(g) under the equilibrium condition 15 atm. The value of K_p is:

(A) 16 (B) 10 (C) 20 (D) 25

17. The order of increasing bond order for the diatomic species O₂, O₂⁺,O₂^-,O₂^2- is:

(A) O₂^2-<>2^-₂₂⁺

(B) O₂₂⁺ <>2^- <>2^2-

(C) O₂⁺<>2<>2^- <>2^2-

(D) O₂^-<>2^2-<>2⁺<>2

18. The bond angle in I₃^-is :

(A) 90° (B) 104° (C) 120° (D)180°

19. The number of ions present in the unit cell of cesium chloride (CsCl) is:

(A) 6

(B) 4

(C) 2

(D) 8

20. The crystal field stabilization energy and the spin-only magnetic moment of [CoF₆]^4- are, respectively:

(A) 0.4 r₀ and 4.9 B.M

(B) 0.8 r₀ and 3.8 B.M

(C) 1.8 r₀ and 1.7 B.M

(D) 2.4 r₀ and 0 B.M

21. The reaction of H₃BO₃ with HF yields aproduct, which upon introduction into a flame gives a characteristic green coloration. The product is:

(A) BH₃

(B) B₂H₆

(C) B₂O₃

(D) BF₃

22. Graphite sublimes at a very high temperature (3700 °C). this is due to:

(A) Weak covalent interactions in the solid and stonger or more covalent interactions in the gas phase

(B) Strong covalent interactions in the solid and weaker or fewer covalent interactions in the gas phase

(C) Strong covalent interactions in the solid and strong covalent interactions in the gas phase

(D) Weak covalent interactions in the solid and stronger ionic interactions in the gas phase

23. The nickel (II) complex [NiCl₂(PPh₃)₂] is paramagnetic. The analogous complex of palladium (II) is diamagnetic. The number of isomers that will exist for each of these formlations respectively are:

(A) 1, 1

(B) 2, 2

(C) 1, 2

(D) 2, 1

29. The perhydroxylation of maleic acid and fumaric acids using KMnO₄ leads respectively to the following tartaric acids:

(A) meso and meso

(B) d,l racemate and meso

(C) meso and d,l racemate

(D) d,l racemate and d,l racemate

SOLUTIONS

1. (A) 2. (D) 3. (C) 4. (B) 5.(B) 6. (A)

7. (D) 8. (A) 9. (C) 10. (C) 11. (C) 12. (B)

13. (A) 14. (A) 15. (D) 16. (C) 17. (C) 18. (D)

19. (C) 20. (B) 21. (D) 22. (B) 23. (C) 24. (A)

25. (A) 26. (C) 27. (D) 28. (C) 29. (C) 30. (A)

MICROBIOLOGY

Q.1 – Q.10 carry one mark each

1. The Scientist who developed aseptic methods using phenol to prevent infections was

(A) Robert Koch (B) John Tyndall

(C) Paul Ehrlich (D) Joseph Lister

2. The organism Robert Koch used first to propose Koch’s postulates was

(A) Mycobacterium tuberculosis

(B) Salmonella typhimurium

(C) Bacillus anthracis

(D) Klebsiella pneumoniae

3. The primary strain used for staining endospore is

(A) Crystal violet (B) Malachite green

(C) Safranin (D) Carbol fuchsin

4. The engulfment causing bacteria by macrophages was discovered by

(A) Emil von Behring

(B) Elie Metchnikoff

(C) shibasburo kitasato

(D) J. Bordet

5. The two enzymes of glyoxylate cycle are

(A) Isocitrate dehydrogenase, a-ketoglutarate dehydrogenase

(B) Isocitrate lyase, a-ketoglutarate dehydrogenase

(C) Isocitrate lyase, Malated synthase

(D) Malated synthase, Isocitrate dehydrogenase

6. Nitrosomona europaea is chemolithotroph in which electron donor and electron acceptor, respectively are

(A) NH₄⁺, O₂ (B) H₂, O₂

(C) NO₂^-, O₂ (D) H₂S, NO₃^-

7. In Gram negative bacteria, the flagellum is attached to the cytoplasmic membrane by the rings

(A) S ring only (B) S and M rings

(C) P ring (D) P and L rings

8. In Rhizobium-legume symbiotic nitrogen fixation, oxygen –sensitive nitrogenase is protected by leghemoglobin. The ratio of leghemoglobin–bound O₂ to free O₂ is

(A) 10:1 (B) 100:1

(C) 1,000:1 (D) 10,000:1

9. Nonphosphorylated Entner Doudoroff pathways (EDP) is operative in species of

(A) Pyrococcus (B) Streptococcus

(C) Micrococcus (D) Staphylocous

10. A ‘regulon’ is defined as

(A) A set of operons that are functionally coordinated

(B) A master gene regulating the function of a set of genes

(C) All the regulatory genes of the genome

(D) The genes present in the control region of an operon

Q.11 – 30 carry two marks each

11. In TCA cycle, both carbons of acetyl CoA are oxidized to CO₂ at two steps which are

(A) Cis-aconitate ® Isocitrate ® a-Ketoglutarate

(B) a-Ketoglutarate ® Succinate ® Fumarate

(C) Isocitrate ® a-Ketoglutarate ® Succinate

(D) Citrate ® Cis-aconitate ® Isocitrate

12. Cells of Escherichia coli grown on mineral salts medium with glycerol as carbon source, are harvested exposed to three different inducers of lac operon. Their inducing efficiencies are

(A) TMG

(B) Lactose

(C) IPTG

(D) TMG

13. A bacterial suspension when counted in Petroff – Hausser counting chamber shoed on average 20 bacteria in one large square (each large square = 1/25 mm²). The number of bacteria/ml of the suspension is

(A) 25´10⁶ (B) 50´10⁶ (C) 10´10⁷ (D) 25´10⁷

14. Pseudomonas species metabolize a wide range of organic compounds through b-ketoadipate whose structure is

(A) CH₃.CH₂.CO.CH₂.COOH

(B) HOOC.CH₂.CH₂.CO.COOH

(C) HOOC.CH₂.CH₂.CO.COOH

(D) HOOC.CH₂.CH₂.CO.CH₂.COOH

15. In a different planet codons have bases instead of three and there are four termination codons as against three found in out planet. Which of the following statements will Not hold true in 4 base codon planet assuming there is no evolutionary selection?

(A) The number of codons will be too few to code for all twenty amino acids

(B) There will be greater codon degeneracy than in earth

(C) The number of t – RNA genes will be more compared to earth

(D) The sizes of proteins will be generally longer

16. In most phototropic and autotrophic organisms, CO₂ is fixed by RubisCO via Calvin cycle. The sugar into which CO₂ gets fixed is

(A) Ribulose – 5 – Phosphate

(B) Glyceraldehyde – 3 – phosphate

(C) 1, 3 – Bisphosphoglycerate

(D) Ribulose – 1, 5 – bisphosphate

17. The genome size of the following organism, are in the order

(A) Haemophilus influenzae>Saccharomyces cerevisiae>Escherichia coli>f´174

(B) Escherichia coli >Saccharomyces cerevisiae> Haemophilus influenzae >f´174

(C) Saccharomyces cerevisiae> Escherichia coli> Haemophilus influenzae>f´174

(D) Saccharomyces cerevisiae>Haemophilus influenzae>f´174>Escherichia coli

18. The following are the number of germ line genes for heavy and light chains in an individual. Calculate the approximate number of diverse IgG (Kappa) molecules that the individual can generate not taking into account somatic mutation

Germline genes Heavy chain K chain

V 50 40

D 30 0

J 6 5

(A) 131 (B) 9,200

(C) 18,00,000 (D) 36,00,000

19. A strain of Mycobacterium tuberculosis was found to be resistance to INH, streptomycin and rifamycin at 10^-5,10^-6,

10^-7 frequencies, respectively. The frequency of appearance of a strain resistance to all three compounds is

(A) 10^-5 (B) 10^-6 (C) 10^-11 (D) 10^-18

20. In Escherichia coli the number of molecules per cell occur in the following order

(A) tRNA

(B) DNA

(C) rRNA

(D) DNA

21. Switch recombination does not take place among the immunoglobulin genes

(A) IgM® IgD (B) IgM àIgG1

(C) IgM à IgE (D) IgM à IgA

22. EMB (eosin – methylene blue) agar is used to differentiate Escherichia coli from Enterobacter aerogenes. The green metallic sheen of the colonies is due to

(A) Eosin and methylene blue combine to produce a precipitate under neutral conditions (E.aerogenes)

(B) Eosin and methylene blue combine to produce a precipitate under acidic conditions (E.coli)

(C) Methylene blue gets precipitated under acid conditions (E.coli)

(D) Eosin gets precipitated under neutral conditions (E.aerogenes)

23. UV spectroscopy is not used to quantitate the compounds based on absorbance

(A) Nucleic acids have absorbance peak at 260nm

(B) NAD(P)H have absorbance peak at 340nm

(C) Aromatic amino acids have absorption maxima about 280nm

(D) Sulfur containing amino acids absorbance at 270nm

24. Luminous bacterium (Vibrio fischeri) and flashlight fish (Photoblepheron palpebratus) provide an interesting symbiotic association. In the luciferase reaction, the products are

(A) FMN + RCOOH + H₂O

(B) RCOOH + H₂O + light

(C) FMN + RCOOH + H₂O + light

(D) FMNH₂ + RCOOH + H₂O + light

25. The flagellate Monas stigmatica (6 mm long) swims at the speed of 50 cell lengths per second. The distance it covers in 1 hour is

(A) 1.08 cm (B) 10.80cm (C) 10.8m (D) 1.08m

26. The serotypes of Salmonella sp. Are due to

(A) Lipid A structure

(B) Core polysaccharide containing KDO and heptose

(C) Unusual sugars in O – side chain

(D) Both Lipid A structure and core polysaccharide

27. The property not possessed by Archaebacteria is

(A) They have pseudomurein in their cell walls

(B) Their lipids have ether linkage

(C) They have N – acetylglucosamine and N – acetyltalosaminuronic acid as repeating alternating units in the backbone

(D) They have D and L amino acids in their short peptide chain

28. Which of the following properties of diphtheria toxin is not true

(A) The nicked toxin is biologically and immunologically identical to unnicked toxin

(B) On reduction with GSH, chains A and B are separable

(C) Diptheria toxin inhibits protein synthesis by ADP – ribosylating EF2

(D) Chain A alone is toxic to animals and whole cells

29. The following statements are made regarding incorporation of 5 – bromodeoxyuridine into DNA

a. 5 – bromodeoxyridine substitutes thymidine in DNA

b. The minimum number of DNA replication cycles required to observe mutation is two

c. 5 – bromodeoxyuridine produces GCàAT transition

d. 5 – bromodeoxyuridine generates deletion mutants

(A) (a) and (c) (B) (a) and (b)

(C) (c) and (d) (D) (b) and (c)

30. In a bacterial cell culture the initial cell population (N₀) was 10³cells/ml. In 6 hours and 40 minutes, it has gone through 20 generations. The final cell population (N_t) and growth rate constant (K), respectively are

N_t K

(A) 10⁹cells/ml and 3

(B) 10⁸cells/ml and 4

(C) 10⁷cells/ml and 5

(D) 10⁶cells/ml and 6

Solution

1. (D) 2. (C) 3. (B) 4. (B) 5. (C) 6. (A)

7. (B) 8. (A) 9. (A) 10. (B) 11. (C) 12. (A)

13. (A) 14. (D) 15. (C) 16. (D) 17. (C) 18. (B)

19. (C) 20. (A) 21. (A) 22. (B) 23. (D) 24. (C)

25. (A) 26. (C) 27. (D) 28. (D) 29. (B) 30. (A)