GATE 2015 Question Paper with Answer Keys for Biotechnology (BT)

Q. 1 – Q. 25 carry one mark each.

Q.1 Which one of the following complement proteins is the initiator of the membrane attack complex?

(A) C3a

(B) C3b

(D) C5b

Ans: (D) C5b

Q.2 Levinthal’s paradox is related to

(A) protein secretion

(B) protein degradation

(D) protein trafficking

Ans: (C) protein folding

Q.3 Which one of the following is a second generation genetically engineered crop?

(A) Bt brinjal

(B) Roundup soyabean

(D) Bt rice

Ans: (C) Golden rice

Q.4 Based on the heavy chain, which one of the following antibodies has multiple subtypes?

(A) IgM

(B) IgD

(D) IgG

Ans: (D) IgG

Q.5 The cytokinetic organelle in plant cells is

(A) centriole

(B) phragmoplast

(D) chromoplastid

Ans: (B) phragmoplast

Q.6 Anergy refers to

(A) mitochondrial dysfunction

(B) allergy to environmental antigens

(D) a state of no energy

Ans: (C) unresponsiveness to antigens

Q.7 ABO blood group antigens in humans are differentiated from each other on the basis of

(A) sialic acid

(B) lipids

(D) glycoproteins

Ans: (D) glycoproteins

Q.8 Which one of the following organisms is used for the determination of phenol coefficient of a
disinfectant?

(A) Salmonella typhi

(B) Escherichia coli

(D) Bacillus psychrophilus

Ans: (A) Salmonella typhi

Q.9 A single subunit enzyme converts 420 µmoles of substrate to product in one minute. The activity
of the enzyme is __ x 10^-6 Katal.

Ans: 7

Q.10 Which one of the following amino acids has the highest probability to be found on the surface of a typical globular protein in aqueous environment?

(A) Ala

(B) Val

C) Arg

(D) Ile

Ans: C) Arg

Q.11 Which one of the following is NOT a product of denitrification in Pseudomonas?

(A) N2

(B) N2O

(D) NH4⁺

Ans: (D) NH4⁺

Q.12 The determinant of the matrix $latex \begin{bmatrix}3&0&0\2&5&0\6&-8&-4\end{bmatrix}$ is______.

Ans:-60

Q.13 Which one of the following features is NOT required in a prokaryotic expression vector?

(A) oriC

(B) Selection marker

(D) Ribosome binding site

Ans: (C) CMV promoter

Q.14 Production of monoclonal antibodies by hybridoma technology requires

(A) splenocytes

(B) osteocytes

(D) thymocytes

Ans: (A) splenocytes

Q.15 Which one of the following is INCORRECT about a typical apoptotic cell?

(A) Phosphatidylserine is presented on the outer cell surface

(B) Cytochrome c is released from mitochondria

(D) Annexin-V binds to the cell surface

Ans: (C) Mitochondrial membrane potential does not change

Q.16 Identify the file format given below:

P1; JMFD
Protein X – Homo sapiens
MKALTARQQEVFDLIRDHISRTLRQQGDWL

(A) GDE

(B) FASTA

(D) GCG

Ans: (C) NBRF

Q.17 Which one of the following relations holds true for the specific growth rate (µ) of a microorganism
in the death phase?

(A) µ = 0

(B) µ < 0

(D) 0 < µ < µmax

Ans: (B) µ < 0

Q.18 How many 3-tuples are possible for the following amino acid sequence?
MADCMWDISEASE

(A) 4

(B) 5

(D) 12

Ans: (C) 11

Q.19 How many different protein sequences of 100 residues can be generated using 20 standard amino
acids?

(A)100²⁰

(B) 100 × 20

(D) 100! × 20!

Ans: (C)20¹⁰⁰

Q.20 In DNA sequencing reactions using the chain termination method, the ratio of ddNTPs to dNTPs
should be
(A) 0

(B) < 1

(D) > 1

Ans: (B) < 1

Q.21 Which one of the following graphs represents uncompetitive inhibition?

(A)

(B)

(C)

(D)

Ans: (A)

Q.22 Choose the appropriate pair of primers to amplify the following DNA fragment by the polymerase
chain reaction (PCR).
5’-GACCTGTGG—————————–ATACGGGAT-3’
3’-CTGGACACC—————————–TATGCCCTA-5’
Primers
P. 5’-GACCTGTGG-3’
Q. 5’-CCACAGGTC-3’
R. 5’-TAGGGCATA-3’
S. 5’-ATCCCGTAT-3’

(A) P and R

(B) P and S

(D) Q and S

Ans: (B) P and S

Q.23 Consider the following infinite series:
1 + r + r² + r³ + … … … . . .∞
If r = 0.3, then the sum of this infinite series is _.

Ans: 1.40 to 1.43

Q.24 2x₁ + x₂ = 3
5x₁ + bx₂ = 7.5

The system of linear equations in two variables shown above will have infinite solutions, if and only if, ܾ is equal to __.

Ans: Ans: 2.5

Q.25 The interaction between an antigen (Ag) and a single-chain antibody (Ab) was studied using Scatchard analysis. The result is shown below.

The affinity of interaction and the total concentration of antibody, respectively, can be determined from

(A) slope and Y-intercept

(B) Y-intercept and slope

(D) slope and X-intercept

Ans: (D) slope and X-intercept

Q. 26 – Q. 55 carry two marks each.

Q.26 An isolated population on an island has the following genotypic frequencies:

Genotype	AA	Aa	aa
Frequency	0.3	0.4	0.3

Assuming that there are only two alleles (A and α) for the gene, the genotypic frequency of AA in the next generation will be __.

Ans: 0.25

Q.27 How many rooted and unrooted phylogenetic trees, respectively, are possible with four different sequences?

(A) 3 and 15

(B) 15 and 3

(D) 12 and 3

Ans: (B) 15 and 3

Q.28 Match the compounds in Group I with the correct entries in Group II.

Group I	Group II
P) Cyanide	1) K+ ionophore
Q) Antimycin A	2) Electron transfer from cytochrome b to cytochrome c1
R) Valinomycin	3) F1 subunit of ATP synthase
S) Aurovertin	4) Cytochrome oxidase
	5) Adenine nucleotide translocase

(A) P-5, Q-2, R-3, S-1

(B) P-5, Q-2, R-1, S-3

(D) P-4, Q-5, R-3, S-1

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

Q.29 What are the eigenvalues of the following matrix?

$latex \begin{bmatrix}1&1\-2&4\end{bmatrix}$

(A) 2 and 3

(B) −2 and 3

(D) −2 and −3

Ans: (A) 2 and 3

Q.30 For a discrete random variable X, ran(X) = {0, 1,2,3} and the cumulative probability F(X) is shown below:

X	0	1	2	3
F(X)	0.5	0.6	0.8	1

The mean value of X is __.

Ans: 1.1

Q.31 Match the drugs in Group I with their mechanism of action in Group II.

Group I	Group II
P) Paclitaxel	1) Inhibits protein translation
Q) Colchicine	2) Inhibits microtubule depolymerization
R) Etoposide	3) Inhibits DNA replication
S) Methotrexate	4) Alkylates DNA
	5) Inhibits dihydrofolate reductase
	6) Inhibits microtubule polymerization

(A) P-1, Q-6, R-3, S-4

(B) P-2, Q-6, R-3, S-5

(D) P-2, Q-3, R-6, S-4

Ans: (B) P-2, Q-6, R-3, S-5

Q.32 The limit of the function $latex \left(1+\frac xn\right)^n$ as n → ∞ is

(A) ln x

(B) $latex \ln\frac1x$

(D) e^x

Ans: (D) e^x

Q.33 Match the cells in Group I with their corresponding entries in Group II.

Group I	Group II
P) Mast cells	1) Activation of the complement pathway
Q) Natural killer cells	2) Expression of CD56
R) Neutrophils	3) Contains azurophilic granules
S) Dendritic cells	4) Defense against helminthic infection
	5) Production of antibodies specific to bacteria
	6) Contains long membranous projections

(A) P-4, Q-2, R-3, S-5

(B) P-4, Q-2, R-3, S-6

(D) P-3, Q-1, R-2, S-6

Ans: (B) P-4, Q-2, R-3, S-6

Q.34 Oxygen transfer was measured in a stirred tank bioreactor using dynamic method. The dissolved oxygen tension was found to be 80% air saturation under steady state conditions. The measured oxygen tensions at 7 s and 17 s were 55% and 68% air saturation, respectively. The volumetric mass transfer coefficient K_La ____________s^-1.

Ans: 0.065 to 0.078

Q.35 Match the microorganisms in Group I with their fermentation products in Group II.

Group I	Group II
P) Leuconostoc mesenteroides	1) Cobalamin
Q) Rhizopus oryzae	2) Sorbose
R) Gluconobacter suboxydans	3) Dextran
S) Streptomyces olivaceus	4) Lactic acid
	5) Butanol

(A) P-5, Q-4, R-2, S-1

(B) P-5, Q-3, R-2, S-4

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

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

Q.36 Plasmid DNA (0.5 μg) containing an ampicillin resistance marker was added to 200 μl of competent cells. The transformed competent cells were diluted 10,000 times, out of which, 50 μl
was plated on agar plates containing ampicillin. A total of 35 colonies were obtained. The transformation efficiency is __× 10⁶ cfu∙μg^-1.

Ans: 2.8

Q.37 Match the reagents in Group I with their preferred cleavage sites in Group II.

Group I	Group II.
P) Cyanogen bromide	1) Carboxyl side of methionine
Q) o-Iodosobenzoate	2) Amino side of methionine
R) Hydroxylamine	3) Carboxyl side of tryptophan
S) 2-Nitro-5-thiocyanobenzoate	4) Amino side of cysteine
	5) Asparagine-glycine bonds

(A) P-1, Q-3, R-5, S-4

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

(D) P-4, Q-2, R-5, S-3

Ans: (A) P-1, Q-3, R-5, S-4

Q.38 Saccharomyces cerevisiae produces ethanol by fermentation. The theoretical yield of ethanol from 2.5 g of glucose is __ g.

Ans: 1.20 to 1.30

Q.39 Choose the CORRECT sequence of steps involved in cytoplast production.

(A) Digestion of cell wall → protoplast viability → cybrid formation → osmotic stabilizer

(B) Osmotic stabilizer → digestion of cell wall → protoplast viability → cybrid formation

(D) Osmotic stabilizer → digestion of cell wall → cybrid formation → protoplast viability

Ans: (B) Osmotic stabilizer → digestion of cell wall → protoplast viability → cybrid formation

Q.40 Match the antibiotics in Group I with their modes of action in Group II

Group I	Group II
P) Chloramphenicol	1) Inhibits protein synthesis by acting on 30S ribosomal subunit
Q) Rifampicin	2) Interferes with DNA replication by inhibiting DNA gyrase
R) Tetracycline	3) Inhibits protein synthesis by acting on 50S ribosomal subunit
S) Quinolone	4) Interferes with RNA polymerase activity
	5) Inhibits β-lactamase activity

(A) P-1, Q-2, R-3, S-5

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

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

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

Q.41 The diameters of a large and a small vessel are 1.62 m and 16.2 cm, respectively. The vessels are geometrically similar and operated under similar volumetric agitated power input. The mixing time in the small vessel was found to be 15 s. Determine the mixing time (in seconds) in the large vessel.

(A) 15

(B) 30

(D) 122

Ans: (C) 61

Q.42 If $latex A=\begin{bmatrix}4&2\1&3\end{bmatrix}$, then A² + 3A will be

(A) $latex \begin{bmatrix}30&20\10&20\end{bmatrix}$

(B) $latex \begin{bmatrix}28&10\4&18\end{bmatrix}$

(D) $latex \begin{bmatrix}20&10\5&15\end{bmatrix}$

Ans: (A) $latex \begin{bmatrix}30&20\10&20\end{bmatrix}$

Q.43 Consider the following multiple sequence alignment of four DNA sequences. $latex \begin{array}{cccc}A&C&T&A\A&C&T&G\A&G&T&C\A&G&C&T\end{array}$
Shannon’s entropy of the above alignment is __.

Ans: 3.80 to 3.82

Q.44 The K_i of a novel competitive inhibitor designed against an enzyme is 2.5 μM. The enzyme was assayed in the absence or presence of the inhibitor (5 μM) under identical conditions. The K_m in the presence of the inhibitor was found to be 30 μM. The K_m in the absence of the inhibitor is __ μM.

Ans: 10

Q.45 A heterozygous tall plant (Tt) was crossed with a homozygous dwarf plant (tt). The resultant seeds were collected. If five seeds are chosen at random, then the probability (in %) that exactly two of these seeds will yield dwarf plants is __.

Ans: 31.0 to 31.3

Q.46 Assuming random distribution of nucleotides, the average number of fragments generated upon digestion of a circular DNA of size 4.3 × 10⁵ bp with AluI (5’-AG↓CT-3’) is _× 10³.

Ans: 1.6 to 1.7

Q.47 A synchronous culture containing 1.8 × 10⁵ monkey kidney cells was seeded into three identical flasks. The doubling time of these cells is 24 h. After 24 h, the cells from all the three flasks were pooled and dispensed equally into each well of three 6-well plates. The number of cells in each well will be _× 10⁴.

Ans: 2

Q.48 An in vitro translation system can synthesize peptides in all three reading frames of the RNA template. When 5’- UCUCUCUC—-(UC)_n—UCUCUCUC – 3’ was used as the template in this in
vitro translation system, the synthesized peptides contained 50% each of serine and leucine. When 5’- CCUCCUCCU—(CCU)_n–CCUCCU – 3’ was used as the template, the synthesized peptides
contained 33.3% each of serine, leucine, and proline. Deduce the codon for proline.

(A) UCU

(B) CUC

(D) UCC

Ans: (C) CCU

Q.49 Three distinct antigens X, Y and Z were used to raise antibodies. Antigen Z was injected in a mouse on day zero followed by the administration of antigens X and Y on day 28. A second
injection of antigen X was administered on day 70. The antibody titers were monitored in the serum every day and the results are shown below:

Which one of the following statements regarding the antibody titers in the serum is INCORRECT?

(A) Z-specific IgG will be high on day 14

(B) X-specific antibody titer will be high on day 84

(D) Y-specific IgG will be high on day 84

Ans: (D) Y-specific IgG will be high on day 84

Q.50 The standard free energy change (ΔG′°) for ATP hydrolysis is −30 kJ∙mole^-1. The in vivo concentrations of ATP, ADP and P_i in E. coli are 7.90, 1.04 and 7.90 mM, respectively. When E.
coli cells are cultured at 37 ºC, the free energy change (ΔG) for ATP hydrolysis in vivo is _ kJ∙mole^-1.

Ans: -48 to -46

Q.51 In a fed-batch culture, 200 g ∙ L^-1 glucose solution is added at a flow rate of 50 L∙h^-1. The initial culture volume (at quasi steady state) and the initial cell concentration are 600 L and 20 g ∙ L^-1,
respectively. The yield coefficient (Y_x/s) is 0.5 g cell mass∙g substrate^-1. The cell concentration (g ∙ L^-1) at quasi steady state at t=8 h is

(A) 40

(B) 52

(D) 68

Ans: (B) 52

Q.52 Cytoplasmic extract from the wild type strain of a bacterium has the ability to convert a colorless substrate (S) to a colored product (P) via three colorless intermediates X, Y and Z, in that order. Each step of the pathway involves a specific enzyme coded by a distinct gene. Four mutant strains (a^– , b^–, c^–, d^–) were isolated, whose extracts are incapable of producing the colored product in the presence of S. In a series of experiments, extracts from the individual mutants were incubated with X, Y, or Z and scored for color development. The data are summarized in the table below. (Yes: color developed, No: no color developed)

Based on the data, which one of the following is the correct order of enzymes involved in the pathway?

Ans: (D)

Q.53 Samples of bacterial culture taken at 5 PM and then the next day at 5 AM were found to have 10⁴and 10⁷ cells∙mL^-1, respectively. Assuming that both the samples were taken during the log phase of cell growth, the generation time of this bacterium will be ______________h.

Ans: 1.20 to 1.22

Q.54 Biomass is being produced in a continuous stirred tank bioreactor of 750 L capacity. The sterile feed containing 8 g ∙ L^-1glucose as substrate was fed at a flow rate of 150 L ∙ h^-1. The microbial
system follows Monod’s model with μm = 0.4 h^-1, Ks = 1.5 g ∙ L^-1 and Y_x/s = 0.5 g cell mass∙g substrate^-1. Determine the cell productivity (g ∙ L^-1 ∙ h^-1) at steady state.

(A) 0.85

(B) 0.65

(D) 0.25

Ans: (B) 0.65

Q.55 A linear double stranded DNA of length 8 kbp has three restriction sites. Each of these can either be a BamHI or a HaeIII site. The DNA was digested completely with both enzymes. The products were purified and subjected to an end-filling reaction using the Klenow fragment and [α-³²P]-dCTP. The products of the end-filling reaction were purified, resolved by electrophoresis, stained with ethidium bromide (EtBr) and then subjected to autoradiography. The corresponding images are shown below.

The numbers below each band in the sample lane in the autoradiograph represent their mean signal intensity in arbitrary units. Which one of the following options is the correct restriction map of the DNA?

Ans:

END OF THE QUESTION PAPER