GATE Exam 2021 Biotechnology (BT) Question Paper With Answer Key



GA-General Aptitude

Q.1 – Q.5 Multiple Choice Question (MCQ), carry ONE mark each (for each wrong answer: – 1/3).

1. The ratio of boys to girls in a class is 7 to 3.

Among the options below, an acceptable value for the total number of students in the class is:

(A)  21

(B)  37

(C)  50

(D)  73

Answer: (C)

2. A polygon is convex if, for every pair of points, P and Q belonging to the polygon, the line segment PQ lies completely inside or on the polygon.

Which one of the following is NOT a convex polygon?

Answer: (A)

3. Consider the following sentences:

(i) Everybody in the class is prepared for the exam.

(ii) Babu invited Danish to his home because he enjoys playing chess.

Which of the following is the CORRECT observation about the above two sentences?

(A)  (i) is grammatically correct and (ii) is unambiguous

(B)  (i) is grammatically incorrect and (ii) is unambiguous

(C)  (i) is grammatically correct and (ii) is ambiguous

(D)  (i) is grammatically incorrect and (ii) is ambiguous

Answer: (C)

4. A circular sheet of paper is folded along the lines in the directions shown. The paper, after being punched in the final folded state as shown and unfolded in the reverse order of folding, will look like _______.

Answer: (A)

5. _____ is to surgery as writer is to ________

Which one of the following options maintains a similar logical relation in the above sentence?

(A)  Plan, outline

(B)  Hospital, library

(C)  Doctor, book

(D)  Medicine, grammar

Answer: (C)

Q.6 – Q. 10 Multiple Choice Question (MCQ), carry TWO marks each (for each wrong answer: – 2/3).

6. We have 2 rectangular sheets of paper, M and N, of dimensions 6 cm × 1 cm each. Sheet M is rolled to form an open cylinder by bringing the short edges of the sheet together. Sheet N is cut into equal square patches and assembled to form the largest possible closed cube. Assuming the ends of the cylinder are closed, the ratio of the volume of the cylinder to that of the cube is _______

(A)  π/2

(B)  3/π

(C)  9/π

(D)  3π

Answer: (C)


Details of prices of two items P and Q are presented in the above table. The ratio of cost of item P to cost of item Q is 3:4. Discount is calculated as the difference between the marked price and the selling price. The profit percentage is calculated as the ratio of the difference between selling price and cost, to the cost 

The discount on item Q, as a percentage of its marked price, is ______

(A)  25

(B)  12.5

(C)  10

(D)  5

Answer: (C)

8. There are five bags each containing identical sets of ten distinct chocolates. One chocolate is picked from each bag.

The probability that at least two chocolates are identical is ___________

(A)  0.3024

(B)  0.4235

(C)  0.6976

(D)  0.8125

Answer: (C)

9. Given below are two statements 1 and 2, and two conclusions I and II.

Statement 1: All bacteria are microorganisms.

Statement 2: All pathogens are microorganisms.

Conclusion I: Some pathogens are bacteria.

Conclusion II: All pathogens are not bacteria.

Based on the above statements and conclusions, which one of the following options is logically CORRECT?

(A)  Only conclusion I is correct

(B)  Only conclusion II is correct

(C)  Either conclusion I or II is correct.

(D)  Neither conclusion I nor II is correct.

Answer: (C OR D)

10. Some people suggest anti-obesity measures (AOM) such as displaying calorie information in restaurant menus. Such measures sidestep addressing the core problems that cause obesity: poverty and income inequality.

Which one of the following statements summarizes the passage?

(A)  The proposed AOM addresses the core problems that cause obesity.

(B)  If obesity reduces, poverty will naturally reduce, since obesity causes poverty.

(C)  AOM are addressing the core problems and are likely to succeed.

(D)  AOM are addressing the problem superficially.

Answer: (D)

Biotechnology (BT)

Q.1 – Q.17 Multiple Choice Question (MCQ), carry ONE mark each (for each wrong answer: – 1/3).

1. Coronavirus genome consists of

(A)  double-stranded DNA

(B)  double-stranded RNA

(C)  negative-sense single-stranded RNA

(D)  positive-sense single-stranded RNA

Answer: (D)

2. The enzyme that transcribes the eukaryotic genes encoding precursor ribosomal RNAs (pre-rRNAs) of 28S, 18S and 5.8S rRNAs is

(A)  RNA polymerase I

(B)  RNA polymerase II

(C)  RNA polymerase III

(D)  RNA polymerase IV

Answer: (A)

3. Number of unrooted trees in a phylogeny of five sequences is

(A)  3

(B)  15

(C)  105

(D)  945

Answer: (B)

4. Which one of the following methods is used to test the significance of predicted phylogeny?

(A)  Bootstrap

(B)  Maximum likelihood

(C)  Maximum parsimony

(D)  Minimum evolution

Answer: (A)

5. The Cartesian coordinates (x, y) of a point A with polar coordinates (4, π/4) is

(A)  (√3, 2√2)

(B)  (2, 2√3)

(C)  (2√2, √3)

(D)  (2√2, 2√2)

Answer: (D)

6. The order of genes present in a chromosome is as follows.

Which one of the following rearrangements represents a paracentric inversion?

Answer: (B)

7. Which one of the following statements is INCORRECT about hybridoma production?

(A)  Hybridoma cells can use hypoxanthine and thymidine

(B)  DNA synthesis in myeloma cells is blocked by aminopterin

(C)  Hybridoma cells are made to produce polyclonal antibodies

(D)  Polyethylene glycol is used to fuse myeloma cells to B-cells

Answer: (C)

8. is equal to

(A)  1/2x

(B)  1/x

(C)  1/2

(D)  x

Answer: (B)

9. Which one of the following techniques/tools is NOT used for inserting a foreign gene into a cell?

(A)  DNA microarray

(B)  Electroporation

(C)  Gene gun

(D)  Microinjection

Answer: (A)

10. Under standard temperature (T) and pressure (P) conditions, 128g of an ideal gas molecule A occupies a volume of 1L. The gas molecule A obeys the relationship RT PV = 0.25. R and V are universal gas constant and ideal gas volume, respectively. The molecule A is

(A)  CO2

(B)  H2

(C)  N2

(D)  O2

Answer: (D)

11. CRISPR-Cas system is associated with

(A)  adaptive immunity in eukaryotes

(B)  adaptive immunity in prokaryotes

(C)  innate immunity in eukaryotes

(D)  innate immunity in prokaryotes

Answer: (B)

12. The process by which intracellular macromolecules are supplied for lysosomal degradation during nutrient starvation is

(A)  apoptosis

(B)  autophagy

(C)  phagocytosis

(D)  pinocytosis

Answer: (B)

13. The process and instrumentation diagram for a feedback control strategy to maintain the level (h) of a liquid by regulating a valve (V) in a tank is shown below. F1 is inlet liquid flow rate, F2 is outlet liquid flow rate, LT is the liquid level transmitter, LC is the liquid level controller, hsp is the setpoint value of the liquid level, hm is the measured value of the liquid level and PV is the valve pressure.

The manipulating variable(s) is/are

(A)  F1 only

(B)  F2 only

(C)  hm and PV only

(D)  hsp and PV only

Answer: (A)

14. A protein without its prosthetic group is known as

(A)  apoprotein

(B)  hemoprotein

(C)  holoprotein

(D)  lipoprotein

Answer: (A)

15. The enzyme which adds phosphate group to the free 5’ terminus of a DNA sequence is

(A)  adenosine kinase

(B)  alkaline phosphatase

(C)  polynucleotide kinase

(D)  terminal deoxynucleotidyl transferase

Answer: (C)

16. Which one of the following is CORRECT about microbial growth medium?

(A)  Luria-Bertani broth is a synthetic medium

(B)  Nutrient broth is a defined medium

(C)  Sabouraud dextrose agar is a differential medium

(D)  Trypticase soy agar is a complex medium

Answer: (D)

17. The cellular process which utilizes RNA-induced silencing complex to block gene expression is

(A)  RNA editing

(B)  RNA interference

(C)  RNA polyadenylation

(D)  RNA splicing

Answer: (B)

Q.18 – Q.19 Multiple Select Question (MSQ), carry ONE mark each (no negative marks).

18. Which of the following layer(s) is/are formed from the inner cell mass of the blastocyst?

(A)  Ectoderm

(B)  Endoderm

(C)  Mesoderm

(D)  Trophectoderm

Answer: (A; B; C)

19. Which of the following cell organelle(s) is/are surrounded by a single phospholipid membrane?

(A)  Golgi apparatus

(B)  Lysosome

(C)  Mitochondria

(D)  Nucleus

Answer: (A; B)

Q.20 – Q.25 Numerical Answer Type (NAT), carry ONE mark each (no negative marks).

20. The sum of the infinite geometric series 1 + 1/3 + 1/32 + 1/33 + … (rounded off to one decimal place) is ________.

Answer: (1.5 to 1.5)

21. Three balls, colored in blue, green and red, are successively transferred from box A to box B in the order BLUE-GREEN-RED. The probability of a reverse transfer of the balls to the box A in the same order (rounded off to two decimal places) is ________.

Answer: (0.16 to 0.18)

22. Decimal reduction time of a bacterial strain is 20 min. Specific death rate constant in min1 (rounded off to two decimal places) is ________.

Answer: (0.10 to 0.13)

23. The value of  (rounded off to two decimal places) is ________.

Answer: (0.25 to 0.25)

24. A system consists of two reactors, connected by a valve. The first reactor (R1) contains an ideal gas A of volume 5 L and the second reactor (R2) has an ideal gas B of volume 10 L . Initially, the valve is closed and pressure P in R1 and R2 are 9 and 6 atm, respectively. Later, when the valve is opened, the system reaches equilibrium. If the temperature T of both the reactors is maintained constant, the final equilibrium pressure in atm of the system is ________.

Answer: (7 to 7)

25. The enzyme α-amylase used in starch hydrolysis has an affinity constant (Km) value of 0.005 M. To achieve one-fourth of the maximum rate of hydrolysis, the required starch concentration in mM (rounded off to two decimal places) is ________.

Answer: (1.60 to 1.80)

Q.26 – Q.34 Multiple Choice Question (MCQ), carry TWO mark each (for each wrong answer: – 2/3).

26. Which one of the following represents non-growth associated product formation kinetics in a bioprocess system? X and P denote viable cell and product concentrations, respectively.

Answer: (C)

27. Match enzymes in Group I with their corresponding industrial application in Group II.

(A)  P-2, Q-3, R-4, S-1

(B)  P-1, Q-3, R-2, S-4

(C)  P-1, Q-2, R-3, S-4

(D)  P-1, Q-4, R-2, S-3

Answer: (B)

28. Match separation methods in Group I with associated properties in Group II.

(A)  P-4, Q-2, R-1, S-3

(B)  P-3, Q-1, R-2, S-4

(C)  P-1, Q-3, R-2, S-4

(D)  P-1, Q-2, R-4, S-3

Answer: (D)

29. Match the autoimmune diseases in Group I with the corresponding primarily affected organ in Group II.

(A)  P-1, Q-2, R-3, S-4

(B)  P-3, Q-1, R-2, S-4

(C)  P-4, Q-2, R-1, S-3

(D)  P-1, Q-2, R-4, S-3

Answer: (C)

30. Match hypersensitivity types in Group I with their corresponding condition in Group II.

(A)  P-2, Q-3, R-1, S-4

(B)  P-3, Q-1, R-4, S-2

(C)  P-2, Q-3, R-4, S-1

(D)  P-2, Q-1, R-3, S-4

Answer: (D)

31. Which of the following combinations of plant hormones and their associated function are CORRECT?

(A)  P and R only

(B)  P and S only

(C)  Q and R only

(D)  Q and S only

Answer: (C)

32. Which one of the following tools is used to compare all the possible six-open reading frames of a given nucleotide query sequence with all the available six-open reading frames of the nucleotide sequence database?





Answer: (D)

33. In Neurospora crassa, a mutation in the poky gene results in a slow growth phenotype (poky). The results of four crosses are given below.

Which one of the following explains the inheritance mode of poky?

(A)  Episomal inheritance

(B)  Mendelian inheritance

(C)  Mitochondrial inheritance

(D)  X-linked inheritance

Answer: (C)

34. Tertiary structure of a protein consisting of α-helices and β-strands can be determined by

(A)  circular dichroism spectroscopy

(B)  mass spectrometry

(C)  nuclear magnetic resonance spectroscopy

(D)  UV spectroscopy

Answer: (C)

Q.35 – Q.38 Multiple Select Question (MSQ), carry TWO mark each (no negative marks).

35. Which of the following statement(s) is/are CORRECT about Agrobacterium tumefaciens?

(A)  It contains tumor inducing plasmid

(B)  It causes crown gall disease in dicotyledonous plants

(C)  It is a Gram-positive soil bacterium

(D)  It is used in generating transgenic plants

Answer: (A; B; D)

36. Which of the following antimicrobial agent(s) is/are growth factor analog(s)?

(A)  5-Fluorouracil

(B)  Isoniazid

(C)  Sulfanilamide

(D)  Tetracycline

Answer: (A; B; C)

37. Which of the following chemical messenger(s) is/are derivative(s) of tryptophan?

(A)  γ-amino butyric acid

(B)  Indole acetic acid

(C)  Melatonin

(D)  Serotonin

Answer: (B; C; D)

38. Which of the following nucleus/nuclei is/are NMR active?

(A)  1H

(B)  13C

(C)  16O

(D)  32S

Answer: (A; B)

Q.39 – Q.55 Numerical Answer Type (NAT), carry TWO mark each (no negative marks).

39. In a Mendel’s dihybrid experiment, a homozygous pea plant with round yellow seeds was crossed with a homozygous plant with wrinkled green seeds.

F1 intercross produced 560 F2 progeny. The number of F2 progeny having both dominant traits (round and yellow) is ________.

Answer: (315 to 315)

40. A 0.1 mL aliquot of a bacteriophage stock having a concentration of 4 × 109 phages mL1 is added to 0.5 mL of E. coli culture having a concentration of 2 × 108 cells mL1. The multiplicity of infection is ________.

Answer: (4 to 4)

41. If the area of a triangle with the vertices (k, 0), (2, 0) and (0, −2) is 2 square units, the value of k is ________.

Answer: (0 to 0 OR 4 to 4)

42. In a chemostat with a dilution rate of 0.8 h1, the steady state biomass concentration and the specific product formation rate are 8 mol m3 and 0.2 (mol product) (mol biomass)1 h1, respectively. The steady state product concentration in mol m3 is ______.

Answer: (2 to 2)

43. If the values of two random variables (X, Y) are (121, 360), (242, 364) and (363, 362), the value of correlation coefficient between X and Y (rounded off to one decimal place) is ________.

Answer: (0.5 to 0.5)

44. The determinant of matrix  is _________.

Answer: (8 to 8)

45. It is desired to scale-up a fermentation from 1L to 1000L vessel by maintaining a constant power-to-volume ratio. The small fermenter is operated at an agitator speed of 300 rotations per minute (rpm). If the value of scale up factor is 10, agitator speed in rpm (rounded off to the nearest integer) for the large fermenter is ________.

Answer: (64 to 65)

46. The specific growth rate of a mold during exponential phase of its growth in a batch cultivation is 0.15 h1. If the cell concentration at 30h is 33 gL1, the cell concentration in g L1 (rounded off to the nearest integer) at 24h is ________.

Answer: (13 to 14)

47. A sedimentation tank of height 100 cm is used in a conventional activated sludge process to separate a suspension of spherical shaped granular sludge biomass of 0.5 mm diameter. The viscosity of the liquid is 1 cP. The difference in density between the suspended biomass and the liquid is 0.1g cm−3. If the biomass reach their terminal velocity instantaneously, the biomass settling time in min (rounded off to two decimal places) is ________.

Answer: (1.20 to 1.30)

48. In a random mating population, Y and y are dominant and recessive alleles, respectively. If the frequency of Y allele in both sperm and egg is 0.70, then the frequency of Y/y heterozygotes (rounded off to two decimal places) is ________.

Answer: (0.41 to 0.43)

49. Calculate the following integral 

Answer: (2 to 2)

50. A feed stream (F1) containing components A and B is processed in a system comprising of separation unit and a mixer as shown below in the schematic diagram. The mole fractions of the components A and B are xA and xB, respectively. If F1 + F2 = 100 kg h1, the degrees of freedom of the system is ______.

Answer: (6 to 6)

51. A batch cultivation of E. coli follows zeroth order Monod’s growth kinetics. The cell growth is terminated when the residual dissolved oxygen concentration attains 10% of its saturation value and oxygen mass transfer coefficient (kLa) reaches its maximum value (80 h1). The saturation value of dissolved oxygen concentration is 0.007 kg m3. . If the maximum specific growth rate and yield coefficient (YX/O2) are 0.2 h1 and 1.5(kg cells) (kgO2)1, respectively, then the final cell concentration in kg m3 (rounded off to two decimal places) at the end of the batch cultivation is ________.

Answer: (3.70 to 3.80)

52. Milk flowing through a stainless steel inner tube (40 mm inner diameter) of double tube-type heater is to be heated from 10°C to 85°C by saturated steam condensing at 120°C on the outer surface of the inner tube. Total heat transferred (Q) is 146200 kcal h1 and the overall heat transfer coefficient is 750 kcal h1 m2°C1. The total length of the heating tube in m (rounded off to one decimal place) is ________.

Answer: (23.0 to 24.0)

53. A DNA solution of 50μg mL−1 concentration gives an absorbance of 1.0 at 260 nm. An aliquot of 20 μL from a 50μL purified plasmid solution is diluted with distilled water to a total volume of 1000μ The diluted plasmid solution gives an absorbance of 0.550 at 260 nm. The concentration of the purified plasmid in μg μL1 (rounded off to two decimal places) is ________.

Answer: (1.37 to 1.38)

54. The possible number of SalI restriction sites in a 9 kb double-stranded DNA, with all four bases occurring in equal proportion (rounded off to the nearest integer) is ________.

Answer: (2 to 2)

55. A bacterium produces acetic acid from ethanol as per the following reaction 2CH3CH2OH + 2O2 → 2CH3COOH + 2H2O

The thermodynamic maximum yield of acetic acid from ethanol in g g1 (rounded off to two decimal places) is ________.

Answer: (1.90 to 2.00)

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