Class-12 Biology Ch-11 Biotechnology- Principles and Processes MCQs Exam 2027

Chapter 1: Biotechnology – Principles and Processes 

Topic 1: Principles of Biotechnology (Genetic & Bioprocess Engineering)

1. The two core techniques that enabled the birth of modern biotechnology are:

   (A) Genetic engineering and Bioprocess engineering

   (B) Physics and Chemistry

   (C) Ecology and Morphology

   (D) Cytology and Histology

2. The technique of altering the chemistry of genetic material (DNA/RNA) is called:

   (A) Genetic Engineering

   (B) Bioprocess Engineering

   (C) Tissue Culture

   (D) Hybridization

3. Traditional hybridization often leads to the inclusion of:

   (A) Only desirable genes

   (B) Undesirable genes along with desirable genes

   (C) No genes at all

   (D) Only cytoplasm

4. The construction of the first recombinant DNA was done by:

   (A) Stanley Cohen and Herbert Boyer

   (B) Watson and Crick

   (C) Gregor Mendel

   (D) Alexander Fleming

5. The first recombinant DNA was constructed by linking an antibiotic resistance gene with a native plasmid of:

   (A) Salmonella typhimurium

   (B) Escherichia coli

   (C) Bacillus thuringiensis

   (D) Agrobacterium

6. Maintaining sterile conditions in chemical engineering processes to grow only the desired microbe is:

   (A) Bioprocess Engineering

   (B) Genetic Engineering

   (C) Plant Breeding

   (D) Gene Therapy

7. The three basic steps in genetically modifying an organism are identification of DNA with desirable genes, introduction of identified DNA into the host, and:

   (A) Maintenance of introduced DNA in the host and transfer to progeny

   (B) Killing the host cell

   (C) Removing the DNA immediately

   (D) Changing the host’s species

Topic 2: Tools of rDNA Technology – Restriction Enzymes

8. Restriction enzymes were discovered in 1963 in E. coli as a defense against:

   (A) Bacteriophages

   (B) Fungi

   (C) Heat

   (D) Antibiotics

9. The ‘Molecular Scissors’ of genetic engineering are:

   (A) Ligases

   (B) Restriction Endonucleases

   (C) Polymerases

   (D) Transcriptases

10. The first restriction endonuclease to be isolated and characterized was:

    (A) Eco RI

    (B) Hind II

    (C) Bam HI

    (D) Pst I

11. Restriction enzymes belong to a larger class of enzymes called:

    (A) Nucleases

    (B) Proteases

    (C) Lipases

    (D) Polymerases

12. The enzyme that removes nucleotides from the ends of the DNA is:

    (A) Exonuclease

    (B) Endonuclease

    (C) Ligase

    (D) Phosphatase

13. Restriction endonucleases cut DNA at specific base sequences called:

    (A) Palindromic Nucleotide Sequences

    (B) Random Sequences

    (C) Termination Sequences

    (D) Promoter Sequences

14. In the nomenclature of Eco RI, the letter ‘R’ is derived from the:

    (A) Name of the strain (RY 13)

    (B) Species name

    (C) Genus name

    (D) Restriction site

15. The recognition sequence for Hind II consists of how many base pairs?

    (A) 4

    (B) 6

    (C) 8

    (D) 10

16. Eco RI identifies which palindromic sequence?

    (A) 5′-GAATTC-3′

    (B) 5′-AAGCTT-3′

    (C) 5′-GGATCC-3′

    (D) 5′-CTGCAG-3′

17. The ‘sticky ends’ on DNA strands are named so because:

    (A) They are covered in glue

    (B) They form hydrogen bonds with their complementary cut counterparts

    (C) They are made of proteins

    (D) They cannot be joined

18. The enzyme responsible for joining two DNA fragments is:

    (A) DNA Ligase

    (B) Restriction Enzyme

    (C) DNA Polymerase

    (D) Helicase

19. Restriction enzymes cut the strand of DNA a little away from the center of the palindrome sites between:

    (A) The same two bases on the opposite strands

    (B) Different bases on the same strand

    (C) Only at the ends

    (D) Anywhere randomly

20. Bacteria protect their own DNA from restriction enzymes by:

    (A) Methylation of their DNA

    (B) Deleting their DNA

    (C) Using ligase

    (D) Wrapping it in protein

21. The sticky ends facilitate the action of which enzyme?

    (A) DNA Ligase

    (B) DNA Polymerase

    (C) RNA Polymerase

    (D) Exonuclease

22. Each restriction endonuclease functions by ‘inspecting’ the length of a:

    (A) DNA sequence

    (B) RNA sequence

    (C) Protein chain

    (D) Lipid layer

23. Which of the following creates ‘Blunt Ends’ (not sticky)?

    (A) Eco RI

    (B) Eco RV

    (C) Hind III

    (D) Bam HI

24. The source of the enzyme Hind III is:

    (A) Haemophilus influenzae

    (B) Escherichia coli

    (C) Bacillus amyloliquefaciens

    (D) Streptomyces albus

Topic 3: Separation and Isolation of DNA Fragments (Gel Electrophoresis)

25. The technique used to separate DNA fragments is:

    (A) Gel Electrophoresis

    (B) PCR

    (C) Bioreactor

    (D) Downstream processing

26. DNA fragments move towards which electrode in electrophoresis?

    (A) Cathode (Negative)

    (B) Anode (Positive)

    (C) Both

    (D) None

27. DNA fragments are separated on the basis of their:

    (A) Size (Sieving effect)

    (B) Color

    (C) Shape

    (D) Magnetic property

28. The most commonly used matrix for DNA electrophoresis is:

    (A) Agarose

    (B) Polyacrylamide

    (C) Pectin

    (D) Cellulose

29. Agarose is a natural polymer extracted from:

    (A) Seaweeds

    (B) Maize

    (C) Bacteria

    (D) Fungi

30. DNA fragments can be seen only after staining with:

    (A) Ethidium Bromide

    (B) Methylene Blue

    (C) Safranin

    (D) Acetocarmine

31. Under UV light, EtBr-stained DNA fragments appear as:

    (A) Bright orange colored bands

    (B) Blue colored bands

    (C) Black colored bands

    (D) Colorless bands

32. The process of extracting the separated DNA strand from the agarose gel is:

    (A) Elution

    (B) Spooling

    (C) Transformation

    (D) Annealing

33. In the gel, the smaller the fragment size:

    (A) The farther it moves from the wells

    (B) The slower it moves

    (C) It stays in the well

    (D) It disappears

34. DNA fragments are negatively charged because of:

    (A) Phosphate group

    (B) Sugar group

    (C) Nitrogenous base

    (D) Hydrogen bond

35. The ‘Sieving effect’ in electrophoresis is provided by:

    (A) Agarose gel

    (B) Buffer solution

    (C) Electric current

    (D) Ethidium bromide

Topic 4: Cloning Vectors (Plasmids & Bacteriophages)

36. Plasmids and bacteriophages have the ability to replicate within bacterial cells:

    (A) Independently of the control of chromosomal DNA

    (B) Only when linked to chromosome

    (C) Only in the presence of light

    (D) Once every 24 hours

37. The sequence from where replication starts is called:

    (A) Origin of replication (Ori)

    (B) Promoter

    (C) Terminator

    (D) Selectable marker

38. The ‘Ori’ sequence also controls the:

    (A) Copy number of the linked DNA

    (B) Color of the cell

    (C) Shape of the plasmid

    (D) Speed of the bacteria

39. A ‘Selectable Marker’ helps in:

    (A) Identifying and eliminating non-transformants

    (B) Joining DNA

    (C) Cutting DNA

    (D) Translating DNA

40. Normally, the genes encoding resistance to antibiotics like ampicillin are used as:

    (A) Selectable Markers

    (B) Cloning sites

    (C) Origins of replication

    (D) Promoters

41. The most famous artificial plasmid vector is:

    (A) pBR322

    (B) Ti-plasmid

    (C) Lambda phage

    (D) YAC

42. In pBR322, ‘p’ stands for:

    (A) Plasmid

    (B) Protein

    (C) Part

    (D) Plant

43. The ‘rop’ gene in pBR322 codes for:

    (A) Proteins involved in the replication of the plasmid

    (B) Antibiotic resistance

    (C) Restriction enzymes

    (D) Cell wall synthesis

44. pBR322 has antibiotic resistance genes for:

    (A) Ampicillin and Tetracycline

    (B) Penicillin and Insulin

    (C) Kanamycin only

    (D) Chloramphenicol only

45. Presence of more than one recognition site within the vector will generate:

    (A) Several fragments, complicating gene cloning

    (B) Better results

    (C) One single fragment

    (D) High protein yield

46. Insertional inactivation of the lacZ gene results in colonies that are:

    (A) White

    (B) Blue

    (C) Red

    (D) Green

47. The enzyme inactivated during ‘Blue-white screening’ is:

    (A) Beta-galactosidase

    (B) DNA polymerase

    (C) Restriction endonuclease

    (D) Permease

48. In ‘Blue-white screening’, non-recombinant colonies appear blue due to:

    (A) Presence of a chromogenic substrate

    (B) Death of cells

    (C) Production of oxygen

    (D) UV light

49. Agrobacterium tumefaciens delivers a piece of DNA known as:

    (A) T-DNA

    (B) R-DNA

    (C) P-DNA

    (D) M-DNA

50. The Ti-plasmid of Agrobacterium is ‘disarmed’ to be used as a:

    (A) Cloning vector for plants

    (B) Weapon

    (C) Fertilizer

    (D) Pathogen

51. Retroviruses are used as vectors for:

    (A) Animal cells

    (B) Plant cells

    (C) Bacteria

    (D) Fungi

52. The vector used to clone DNA in Yeast is:

    (A) YAC (Yeast Artificial Chromosome)

    (B) BAC

    (C) pBR322

    (D) Ti-plasmid

53. The vector used for Human Genome Project to carry large fragments was:

    (A) BAC and YAC

    (B) pBR322

    (C) SV40

    (D) Disarmed retrovirus

54. If a gene is ligated at the Bam HI site of pBR322, the recombinant will lose resistance to:

    (A) Tetracycline

    (B) Ampicillin

    (C) Both

    (D) Neither

55. The cloning site for Pst I in pBR322 is located within the gene for:

    (A) Ampicillin resistance

    (B) Tetracycline resistance

    (C) Origin of replication

    (D) Rop

Topic 5: Competent Host (For Transformation with rDNA)

56. DNA cannot pass through cell membranes because it is a:

    (A) Hydrophilic molecule

    (B) Hydrophobic molecule

    (C) Neutral molecule

    (D) Small molecule

57. To make bacteria take up a plasmid, they are treated with a specific concentration of:

    (A) Divalent cations (e.g., Calcium)

    (B) Monovalent cations (e.g., Sodium)

    (C) Acids

    (D) Alcohol

58. The ‘Heat Shock’ method involves a temperature of:

    (A) 42°C

    (B) 37°C

    (C) 100°C

    (D) 0°C

59. In ‘Micro-injection’, recombinant DNA is directly injected into the:

    (A) Nucleus of an animal cell

    (B) Cytoplasm of a plant cell

    (C) Cell wall of bacteria

    (D) Mitochondria

60. The ‘Biolistics’ or ‘Gene Gun’ method is suitable for:

    (A) Plants

    (B) Animals

    (C) Viruses

    (D) Humans

61. In the Gene Gun method, DNA is coated onto micro-particles of:

    (A) Gold or Tungsten

    (B) Silver

    (C) Iron

    (D) Platinum

62. The process of increasing the ability of a cell to take up DNA is called:

    (A) Competence

    (B) Resistance

    (C) Pathogenicity

    (D) Virulence

63. Which method uses ‘disarmed’ pathogens to deliver DNA?

    (A) Pathogen-mediated transfer

    (B) Micro-injection

    (C) Gene gun

    (D) Electroporation

Topic 6: Processes of Recombinant DNA Technology (Isolation of DNA)

64. To release DNA from a bacterial cell, we use the enzyme:

    (A) Lysozyme

    (B) Cellulase

    (C) Chitinase

    (D) Protease

65. To isolate DNA from plant tissue, the cell wall is digested by:

    (A) Cellulase

    (B) Lysozyme

    (C) Amylase

    (D) Lipase

66. To isolate DNA from fungus, the enzyme used is:

    (A) Chitinase

    (B) Cellulase

    (C) Lysozyme

    (D) Ribonuclease

67. RNA is removed from the DNA mixture by treatment with:

    (A) Ribonuclease

    (B) Protease

    (C) DNase

    (D) Lipase

68. Proteins are removed during DNA isolation by using:

    (A) Protease

    (B) RNase

    (C) Cellulase

    (D) Pectinase

69. Purified DNA finally precipitates out after the addition of:

    (A) Chilled Ethanol

    (B) Hot water

    (C) Acid

    (D) Ether

70. The collection of precipitated DNA on a glass rod is known as:

    (A) Spooling

    (B) Elution

    (C) Annealing

    (D) Extension

Topic 7: Amplification of Gene of Interest using PCR

71. PCR stands for:

    (A) Polymerase Chain Reaction

    (B) Protein Chain Rate

    (C) Polymerase Carbon Reaction

    (D) Primary Cell Ratio

72. The three steps of a PCR cycle in order are:

    (A) Denaturation, Annealing, Extension

    (B) Extension, Annealing, Denaturation

    (C) Annealing, Extension, Denaturation

    (D) Denaturation, Extension, Annealing

73. The high temperature (approx 94°C) in PCR is used for:

    (A) Denaturation (Separating DNA strands)

    (B) Annealing

    (C) Extension

    (D) Killing the enzyme

74. In the ‘Annealing’ step of PCR, what is joined to the DNA?

    (A) Primers

    (B) Ligase

    (C) Taq Polymerase

    (D) RNA

75. The thermostable DNA polymerase used in PCR is called:

    (A) Taq Polymerase

    (B) DNA Pol I

    (C) Vent Polymerase

    (D) RNA Pol

76. Taq Polymerase is isolated from a bacterium called:

    (A) Thermus aquaticus

    (B) Thermus thermophilus

    (C) E. coli

    (D) Bacillus

77. The ‘Extension’ step in PCR is carried out at which temperature?

    (A) 72°C

    (B) 94°C

    (C) 54°C

    (D) 37°C

78. If 30 cycles of PCR are carried out, the DNA is amplified about:

    (A) 1 Billion times

    (B) 30 times

    (C) 1000 times

    (D) 1 Million times

79. Primers are:

    (A) Small chemically synthesized oligonucleotides

    (B) Large double-stranded DNA

    (C) Protein molecules

    (D) RNA strands

80. PCR was developed by:

    (A) Kary Mullis

    (B) Boyer

    (C) Cohen

    (D) Khorana

81. The ‘Annealing’ temperature in PCR is usually between:

    (A) 40°C – 60°C

    (B) 90°C – 100°C

    (C) 0°C – 10°C

    (D) 70°C – 80°C

Topic 8: Obtaining the Foreign Gene Product (Bioreactors)

82. A protein-encoding gene expressed in a heterologous host is called a:

    (A) Recombinant Protein

    (B) Mutant Protein

    (C) Wild Protein

    (D) Hybrid Protein

83. For large scale production of products, we use:

    (A) Bioreactors

    (B) Test tubes

    (C) Flasks

    (D) Beakers

84. The volume of a typical large-scale bioreactor is:

    (A) 100 – 1000 Liters

    (B) 1 – 10 Liters

    (C) 10,000 Liters

    (D) 50 Liters

85. The most commonly used bioreactors are of the:

    (A) Stirred-tank type

    (B) Shaking type

    (C) Open pond type

    (D) Fixed bed type

86. The ‘Stirrer’ in a bioreactor is designed to:

    (A) Facilitate even mixing and oxygen availability

    (B) Heat the medium

    (C) Kill the microbes

    (D) Filter the product

87. In a continuous culture system, fresh medium is added from one side to maintain cells in:

    (A) Exponential (Log) Phase

    (B) Lag Phase

    (C) Stationary Phase

    (D) Decline Phase

88. Which system in a bioreactor controls the foam?

    (A) Foam control system

    (B) Agitator system

    (C) Aeration system

    (D) Temperature control system

89. The ‘Sparged’ stirred-tank bioreactor uses:

    (A) Bubbles to increase surface area for oxygen transfer

    (B) A solid paddle

    (C) No air

    (D) Manual stirring

90. Optimal growth conditions provided in a bioreactor include:

    (A) Temperature and pH

    (B) Substrate and Salts

    (C) Vitamins and Oxygen

    (D) All of the above

Topic 9: Downstream Processing

91. The processes including separation and purification of the product are collectively called:

    (A) Downstream Processing

    (B) Upstream Processing

    (C) Midstream Processing

    (D) PCR

92. Downstream processing occurs:

    (A) After the biosynthetic stage

    (B) Before the biosynthetic stage

    (C) During the PCR stage

    (D) Before isolation of DNA

93. The product has to be formulated with suitable:

    (A) Preservatives

    (B) Toxins

    (C) DNA

    (D) Bacteria

94. Strict quality control testing for each product is part of:

    (A) Downstream Processing

    (B) Genetic engineering

    (C) Transcription

    (D) Transformation

95. Downstream processing varies from:

    (A) Product to product

    (B) Species to species

    (C) Lab to lab

    (D) Year to year

Topic 10: Miscellaneous & Important Exam Questions (Mixed)

96. DNA is an acidic molecule because of:

    (A) Phosphate group

    (B) Ribose sugar

    (C) Uracil

    (D) Adenine

97. The source of Eco RI is:

    (A) Escherichia coli RY 13

    (B) Escherichia coli K12

    (C) Salmonella

    (D) Agrobacterium

98. Which of the following is NOT a tool of rDNA technology?

    (A) Restriction enzyme

    (B) Vector

    (C) Host

    (D) Mitochondria

99. DNA fragments joined by ligase have which type of bond?

    (A) Phosphodiester

    (B) Hydrogen

    (C) Peptide

    (D) Glycosidic

100. The first step in the isolation of DNA from a plant cell is breaking the:

     (A) Cell wall

     (B) Cell membrane

     (C) Nucleus

     (D) Ribosome

101. Restriction enzymes are also called:

     (A) Biological Scissors

     (B) Biological Glue

     (C) Biological Stitching

     (D) Biological Hammer

102. Bacteriophages are used as vectors because of their:

     (A) High copy number per cell

     (B) Small size

     (C) Low copy number

     (D) Ability to kill humans

103. The recognition site for Pvu I is found in which gene of pBR322?

     (A) Ampicillin resistance

     (B) Tetracycline resistance

     (C) Ori

     (D) Rop

104. A recombinant DNA molecule is produced by joining:

     (A) Foreign DNA and Vector DNA

     (B) Two proteins

     (C) Two carbohydrates

     (D) DNA and RNA

105. PCR is used for the detection of:

     (A) HIV

     (B) Genetic mutations

     (C) Pathogens

     (D) All of the above

106. The DNA polymerase used in PCR is ‘DNA dependent’:

     (A) DNA Polymerase

     (B) RNA Polymerase

     (C) Reverse Transcriptase

     (D) Ligase

107. Which of the following is a palindromic sequence?

     (A) 5′ – MADAM – 3′ (Analogy)

     (B) 5′ – BIOLOGY – 3′

     (C) 5′ – GAATTC – 3′ (Biological)

     (D) Both A and C

108. ‘Chilled Ethanol’ is used because DNA is:

     (A) Insoluble in Ethanol

     (B) Soluble in Ethanol

     (C) Degraded by Ethanol

     (D) Colored by Ethanol

109. Electrophoresis was developed by:

     (A) Tiselius

     (B) Mullis

     (C) Watson

     (D) Southern

110. The temperature of ‘Annealing’ in PCR is generally:

     (A) Lower than Denaturation

     (B) Higher than Denaturation

     (C) Same as Denaturation

     (D) 100°C

111. DNA finger-printing was developed by:

     (A) Alec Jeffreys

     (B) Mullis

     (C) Khorana

     (D) Mendel

112. A ‘Clone’ is a group of organisms produced by:

     (A) Asexual reproduction (genetically identical)

     (B) Sexual reproduction

     (C) Hybridization

     (D) Mutation

113. The Ti-plasmid is found in:

     (A) Agrobacterium

     (B) E. coli

     (C) Yeast

     (D) Rhizobium

114. In pBR322, ‘BR’ stands for:

     (A) Bolivar and Rodriguez

     (B) Boyer and Reed

     (C) Bacteria and Recombinant

     (D) Bihar and Russia

115. Which enzyme is used to remove proteins during DNA isolation?

     (A) Protease

     (B) Lipase

     (C) RNase

     (D) Cellulase

116. The distance between two base pairs in DNA is:

     (A) 0.34 nm

     (B) 3.4 nm

     (C) 2 nm

     (D) 20 nm

117. One full turn of the DNA helix is:

     (A) 3.4 nm

     (B) 0.34 nm

     (C) 20 nm

     (D) 10 nm

118. The specific sequence of DNA recognized by restriction enzyme is:

     (A) Recognition sequence

     (B) Start codon

     (C) Stop codon

     (D) Non-sense sequence

119. The use of living organisms or their components to produce useful products is:

     (A) Biotechnology

     (B) Bioinformatics

     (C) Biogeography

     (D) Biometry

120. Taq Polymerase can withstand temperatures up to:

     (A) 95°C

     (B) 37°C

     (C) 0°C

     (D) 50°C

121. In gel electrophoresis, DNA bands are cut from the gel and extracted. This is:

     (A) Elution

     (B) Spooling

     (C) PCR

     (D) Blotting

122. pBR322 is a:

     (A) Plasmid vector

     (B) Bacteriophage

     (C) Bacterial cell

     (D) Human gene

123. The total number of restriction sites in pBR322 is:

     (A) Multiple (approx 8 famous ones)

     (B) Only one

     (C) Zero

     (D) Hundreds

124. Which enzyme acts as ‘biological stitches’?

     (A) DNA Ligase

     (B) Restriction Endonuclease

     (C) DNA Polymerase

     (D) RNA Polymerase

125. The matrix used in electrophoresis has a:

     (A) Sieving effect

     (B) Heating effect

     (C) Chemical effect

     (D) No effect

126. DNA replication is:

     (A) Semi-conservative

     (B) Conservative

     (C) Dispersive

     (D) Non-conservative

127. Agarose is a:

     (A) Polysaccharide

     (B) Protein

     (C) Lipid

     (D) Amino acid

128. DNA has a net charge that is:

     (A) Negative

     (B) Positive

     (C) Neutral

     (D) Variable

129. Which of the following is used in Gene Therapy?

     (A) Retrovirus

     (B) pBR322

     (C) Agrobacterium

     (D) Bacteria

130. DNA isolation from bacteria requires:

     (A) Lysozyme

     (B) Cellulase

     (C) Chitinase

     (D) All of these

131. The ‘Annealing’ step involves binding of:

     (A) DNA Primers

     (B) DNA Ligase

     (C) RNA Polymerase

     (D) Proteins

132. A Bioreactor is a:

     (A) Vessel for biochemical reactions

     (B) Microscope

     (C) Type of bacteria

     (D) Gene

133. Stirred-tank bioreactors have:

     (A) Curved base for better mixing

     (B) Flat base

     (C) No stirrer

     (D) Square shape

134. Which is used to transfer genes into Dicot plants?

     (A) Ti-plasmid

     (B) pBR322

     (C) Lambda phage

     (D) Retrovirus

135. Restriction enzymes are found naturally in:

     (A) Bacteria

     (B) Viruses

     (C) Humans

     (D) Plants

136. The enzyme that breaks hydrogen bonds in DNA is:

     (A) Helicase

     (B) Ligase

     (C) Polymerase

     (D) Endonuclease

137. Eco RI comes from which organism?

     (A) Escherichia coli

     (B) Bacillus

     (C) Salmonella

     (D) Thermus

138. Gene cloning produces:

     (A) Multiple copies of a gene

     (B) New species

     (C) Mutations

     (D) Proteins only

139. The DNA used as a carrier for transferring a fragment of foreign DNA is:

     (A) Vector

     (B) Host

     (C) Marker

     (D) Promoter

140. Taq Polymerase is a:

     (A) Thermostable enzyme

     (B) Thermolabile enzyme

     (C) Cold-sensitive enzyme

     (D) Lipid

141. Restriction endonucleases are called ‘endonucleases’ because they cut:

     (A) Within the DNA strand

     (B) At the ends

     (C) Only RNA

     (D) Proteins

142. DNA fragments move in the gel according to their:

     (A) Molecular weight / Size

     (B) Color

     (C) Shape

     (D) All of these

143. Transformation is the process by which:

     (A) Bacteria take up foreign DNA

     (B) DNA makes RNA

     (C) RNA makes protein

     (D) Cells die

144. Downstream processing includes:

     (A) Separation and Purification

     (B) PCR and Gel

     (C) Cutting and Joining

     (D) None of these

145. Which is the first step of Southern Blotting?

     (A) Digestion of DNA by restriction enzymes

     (B) Electrophoresis

     (C) Transfer to membrane

     (D) Hybridization