Dr Raja Kamran Afzal submitted a document containing questions about DNA, RNA, and genetic engineering concepts. The document tests knowledge on topics such as DNA structure, DNA replication, transcription, translation, and genetic engineering techniques like cloning, PCR, and restriction enzymes. It contains multiple choice questions with a single correct answer for each.

1. Submitted by Dr Raja Kamran Afzal
1. Which of the following is a key component of a DNA nucleotide?
A) Nitrogenous base.
B) Deoxyribose sugar.
C) Phosphate group.
D) All of these.***
E) None of these.
2. What type of bond connects nucleotides?
A) Phosphodiester.
B) Hydrogen.
C) Ionic.
D) A and B.***
E) None of these.
3. Which of the following statements about the structure of DNA is incorrect?
A) One complete turn requires 3.4nm and 10 base pairs.
B) The backbones of each strand run in opposite directions relative to each other.
C) Each pair of nucleotides is held together by three hydrogen bonds.***
D) The width of the molecule is a constant 2nm.
E) All of these.
4. Which statement is false?
A) RNA and DNA are both composed of nucleotides joined by phosphodiester bonds.
B) RNA and DNA both have secondary and tertiary structure.
C) RNA is always single stranded while DNA is always double stranded.***
D) A and B are both false.
E) None of these (A, B and C are all true statements).
5. The flow of genetic material in microbial cells usually proceeds from
A) Proteins through RNA to DNA
B) RNA through DNA to proteins
C) DNA through RNA to proteins***
D) All of the above
E) None of the above
6. A new copy of a DNA molecule is precisely synthesized during a process called
A) translation

2. B) transcription
C) replication***
D) transduction
E) transfection
7. The final step in gene expression is protein synthesis, or
A) translation
B) transcription***
C) replication
D) transfection
E) transduction
8. DNA polymerase catalyzes the synthesis of DNA in the
A) 3' to 5' direction
B) 5' to 3' direction***
C) both A and B
D) primer to template DNA
E) template DNA to primer
9. The enzymes that unwind short stretches of DNA helix immediately ahead of a
replication fork are
A) single-stranded binding proteins
B) topoisomerases
C) helicases***
D) endonucleases
E) polymerases
10. The enzyme that repairs nicked DNA by forming a phosphodiester bond between
adjacent nucleotides is
A) DNA gyrase
B) helicase
C) DNA ligase***
D) polymerase
E) endonuclease
11. Another name for the RNA polymerase recognition/binding site upstream of a
gene is the
A) promoter***
B) terminator
C) facilitator
D) accommodator

3. E) locator
12. DNA repair mechanisms are able to distinguish newly synthesized DNA strands
from older strands because
A) new strands do not contain cytosine bases
B) old strands are methylated while new strands are not***
C) new strands are methylated while old strands are not
D) both A and B
E) none of the above
13. Which of the following is an example of a DNA vector?
A) A prophage.
B) An Hfr element.
C) An F factor.***
D) All of these.
E) None of these.
14. Which of the following would NOT be a useful selectable marker?
A) A gene encoding a protein that degrades the antibiotic ampicillin.
B) A gene encoding a protein that allows the cell to synthesize histidine.
C) A gene encoding a protein that is an essential structural component of the cell.***
D) All of these are useful selectable markers.
E) None of these are useful selectable markers.
15. Formation of what type of chemical bond is catalyzed by DNA ligase?
A) Glycosidic.
B) Hydrogen.
C) Phosphoester.***
D) Ester.
E) Phosphotriester.
16. Which of these would be an example of subcloning?
A) A recircularized vector is digested with a second restriction enzyme.
B) Part of the insert from a hybrid vector is inserted into a different vector.***
C) Several different restriction enzymes are used to cut a hybrid vector, individually and
in combinations.
D) All of these.
E) None of these.
17. What key feature of Taq polymerase allows PCR to be conveniently performed?

4. A) Taq polymerase does not require primers.
B) Taq polymerase does not require a template.
C) Taq polymerase is not damaged by heating.***
D) Taq polymerase can work at very low temperatures.
E) Taq polymerase is heat labile.
18. Which of the following would you expect to be a drawback to PCR techniques?
A) PCR has the potential to create positive results from very low levels of
contamination.***
B) PCR can be used with very small samples such as single sperm cells.
C) PCR is very rapid; in some cases results can be available in a few hours.
D) All of these.
E) None of these.
19. In choosing a vector, viral vectors typically can carry much larger pieces of DNA
than plasmid vectors, but plasmid vectors are much easier to work with since they do not
kill their host cells. In which of the following situations would you anticipate preferring a
viral vector?
A) You need to clone an entire gene, including regulatory sequences.
B) You are generating a genomic library from an organism with a large genome.
C) You are creating an mRNA library to identify the gene encoding a very large protein.
D) All of these.***
E) None of these.
20. What type of probe would you use for a Western blot experiment?
A) A known DNA sequence.
B) An RNA molecule.
C) A purified protein.
D) An antibody.***
E) An enzyme.
21. Which method of gene transfer involves direct contact between the bacteria?
A) Conjugation.***
B) Transduction.
C) Transformation.
D) Transportation.
E) Transfection.
22. The deliberate modifications of an organism's genetic information by directly
changing its nucleic acid content.
A) genetic engineering***

5. B) population genetics
C) population planning
D) genetic microbiology
E) genetic transformation
23. Enzymes that recognize and cleave specific 4 to 8 base pair sequences
A) DNA ligases
B) helicases
C) restriction endonucleases***
D) non-specific endonucleases
E) DNA lyzing enzymes
24. What is the normal role of restriction endonucleases in bacterial cells?
A) to degrade the bacterial chromosome into small pieces during replication
B) to degrade invading phage DNA***
C) to produce RNA primers for replication
D) to prevent the process of transformation
E) to prevent binary fission
25. Which type of restriction endonuclease cuts the DNA within the recognition site?
A) Type I
B) Type II***
C) Type III
D) Type IV
E) Type V
26. Vectors are:
A) molecules that degrade nucleic acids
B) molecules that are able to covalently bond to and carry foreign DNA into cells***
C) molecules that protect host cells from invasion by foreign DNA
D) molecules that induce cell lysis
E) molecules that help in rapid multiplication of cells
27. Separation of charged molecules is separated based on varying rates of migration
through a solid matrix when subjected to an electric field, is
A) photoreactivation
B) gel electrophoresis***
C) autoradiography
D) gel doc system
E) ELISA

6. 28. The Southern blotting technique depends on
A) similarities between the sequences of probe DNA and experimental DNA***
B) the molecular mass of proteins
C) the amino acid sequence of a protein
D) the rapid degradation of DNA
E) gene sequencing
29. A short (2-20 nucleotide) molecule is
A) plasmid
B) vector
C) oligonucleotide***
D) bacterium
E) fungus
30. A molecular technique in which the DNA sequences between two oligonucleotide
primers can be amplified
A) Southern blotting
B) Northern blotting
C) Polymerase Chain Reaction***
D) Gene sequencing
E) RFLP
31. The enzyme used to covalently bond foreign DNA to a vector plasmid
A) DNA polymerase
B) restriction endonuclease
C) DNA ligase***
D) DNA helicase
E) Amino transferase
32. A genomic library is:
A) a database where the sequence of an organisms genome is stored
B) a collection of many clones possessing different DNA fragments from the same
organisms bound to vectors***
C) a book that describes how to isolate DNA from a particular organism
D) dependent on micro-array only
E) a present in bacterial cells
33. DNA that is obtained using processed mRNA molecules as a template
A) rDNA

7. B) mDNA
C) cDNA***
D) tDNA
E) super DNA
34. For gene probes to be useful they must:
A) be large enough to contain gene-specific sequences
B) be labeled in some manner to allow detection
C) both A and B***
D) be small enough to pass through membrane filters
E) A, B and D
35. Which of the following is not commonly used as vector?
A) artificial chromosome
B) cosmid
C) fungi***
D) both A and B
E) A, B and C
36. In genetic engineering, a chimera is:
A) an enzyme that links DNA molecules
B) a plasmid that contains foreign DNA***
C) a virus that infects bacteria
D) a transgenic animal
E) a restriction endonuclease
37. An animal that has gained new genetic information from the acquisition of foreign
DNA
A) a chimera
B) a transgenic animal***
C) a vector
D) a clone
E) a gnotobiotic
38. Electroporation is:
A) the process of separating charged molecules through a gel maintained in an electric
field
B) the process of combining foreign DNA to an electrically charged vector molecule
C) the process of introducing DNA into cells by the application of high voltage pulses***
D) the process of preventing bacteria to conjugate with the help of electric current

8. E) none of the above
39. In which ways are recombinant DNA techniques playing an important role in
human health?
A) helping to determine the molecular causes of disease
B) producing effective means to express proteins such as insulin and growth hormone
C) by not producing effective means of expression of proteins
D) A and B***
E) A, B and C
40. Which statement regarding recombination is false?
A) Recombination creates new combinations of alleles on a chromosome.
B) Recombination commonly occurs between homologous sequences.
C) Gene conversion may occur during recombination.
D) Sister chromatid exchange is a form of recombination.***
E) A, B and C.
41. Which type of transposable element is only found in eukaryotes (not
prokaryotes)?
A) Transposable elements that move by simple transposition.
B) Transposable elements that move by replicative transposition.
C) Retrotransposons, which move via an RNA intermediate.***
D) All of these.
E) None of these.
42. RT-PCR means
A) reverse transcriptase polymerase chain reaction ***
B) rightward template polymerase chain reaction
C) rotating tube polymerase chain reaction
D) real time polymerase chain reaction
E) None of the above
43. A Southern blot is
A) A technique for the detection of proteins immobilized on a membrane***
B) A technique for the detection of DNA immobilized on a membrane
C) A technique for the detection of RNA in solution
D) A technique invented in Southern America
E) None of the above

9. 44. Cutting and joining. The expected size of DNA fragments generated by an 8-
cutter restriction endonuclease, assuming that DNA is a random sequence of bases, would
be:
A) 65,536 bp***
B) 5,096 bp
C) 256 bp
D) 128 bp
E) 64 bp
45. Gene transfer to animal cells. Which of the following viral vectors has the largest
capacity for foreign DNA?
A) Adenovirus
B) Retrovirus
C) Baculovirus***
D) H1N1
E) Flavivirus
46. What is RAGE?
A) RNA interference by injection of double stranded RNA***
B) Expression of an integrated antisense transgene
C) Gene knockout by homologous recombination
D) A modification of PCR
E) RNA Amplification by Gel Elecrophoresis
47. Which of the technologies listed below is a valuable method for mass-producing
drugs and other useful proteins?
A) recombinant DNA technology***
B) transgenic technology
C) biotechnology
D) gene targeting
E) gene cloning
48. Manufacturing recombinant DNA molecules involves cutting a gene from its
normal location, inserting it into a circular piece of DNA from a bacterial cell, and then
transferring the circle of DNA to cells of another species. Which of the tools below is
used to cut the gene from its normal location?
A) restriction enzyme***
B) plasmid
C) bacteriophage
D) vector

10. E) transposon
49. Human proteins can be produced in the milk or semen of farm animals. True or
false?
A) true***
B) false, proteins cannot be produced in milk
C) false, proteins cannot be produced in semen
D) false, animals are not used for human protein production
E) false, human proteins can only be produced in humans
50. The following are direct detection methods except:
A) Detection of rotavirus antigen in faecal specimens
B) Electron microscopy
C) Polymerase chain reaction
D) Single Radial Haemolysis (SRH)***
E) All of the above
51. The following are examples of viral genome detection (molecular methods)
except:
A) Polymerase chain reaction (PCR)
B) Branched DNA
C) Western blot***
D) Southern blot
E) None of the above
52. A standard Polymerase Chain Reaction (PCR) consists of, except:
A) Denaturation, annealing, and ligation steps***
B) Denaturation, annealing, and extension steps
C) dNTPs
D) Mg++ ions
E) Taq polymerase
53. Safety measures for preventing PCR contamination include, except:
A) Use of filtered pipette tips
B) Separate areas for master mix, template, and PCR product operation
C) Dedicated pipettes for master mix, template, and PCR products
D) Ultraviolet irradiation
E) None of the above***
54. The following statements are usually true, except:

11. A) PCR is more sensitive than branched DNA assays
B) Branched DNA is more sensitive than Ligase chain reaction***
C) Exponential amplification occurs in PCR
D) Linear amplification occurs in branched DNA
E) PCR is extremely liable to contamination
55. What are restriction enzymes?
A) enzymes that are limited (i.e., restricted) in how big they can become
B) DNA helicases
C) plasmids
D) cholinesterases
E) enzymes that cleave through a DNA helix wherever they encounter a specific
sequence of nucleotides***
56. SDS-PAGE has been used
A) to analyze different types of proteins in a biological membrane***
B) to characterize membrane proteins in their native conformation
C) to measure the transport of proteins from the smooth ER to the Golgi
D) to characterize the enzyme activities in the lysosome
E) to isolate nuclear DNA
57. Plasmids are important in biotechnology because they are
A) a vehicle for the insertion of recombinant DNA into bacteria.***
B) surfaces for respiratory processes in bacteria.
C) recognition sites on recombinant DNA strands.
D) surfaces for protein synthesis in eukaryotic recombinants.
E) proviruses incorporated into the host DNA.
58. What is a cloning vector?
A) an agent, such as a plasmid, used to transfer DNA from an in vitro solution into a
living cell***
B) the sticky end of a DNA fragment
C) the laboratory apparatus used to clone genes
D) a DNA probe used to locate a particular gene in the genome
E) the enzyme that cuts DNA into restriction fragments
59. What are the essential characteristics of a cloning vector?
A) Bacterial cells cannot survive without it.
B) Bacterial cells replicate it.
C) Bacterial cells take it up.

12. D) Both B and C are correct.***
E) A, B, and C are correct
60. Gel electrophoresis CANNOT be used as a preparative technique prior to use of other
methods such as
A) Mass spectrometry
B) RFLP
C) PCR
D) Cloning
E) Indirect haemagglutination***
61. Acrylamide must be handled using appropriate safety precautions, because it is a
A) Neurotoxin***
B) Hepatotoxin
C) Aflatoxin
D) Enterotoxin
E) Histotoxin
62. After the electrophoresis is complete, the molecules in the gel can be visualized by
A) Ethidium chloride
B) Silver bromide
C) Coomassie red
D) Ultraviolet light***
E) Light microscopy
63. Gel electrophoresis CANNOT be used in
A) Forensics
B) Molecular biology
C) Genetics
D) Microbiology
E) Histopathology***
64. Acrylamide gels DO NOT consist of following
A) Acrylamide
B) Bisacrylamide
C) SDS
D) Carbonic acid***
E) Tris-Cl buffer with adjusted pH
65. Coomassie Brilliant Blue binds with more affinity to
A) Glycoproteins

13. B) Fibrous proteins
C) DNA proteins***
D) None of the above
E) All of the above
66. Polyacrylamide gel is
A) A natural gel
B) Thermo-labile
C) Chemically inert***
D) Comprised of fixed range of pore sizes
E) All of the above
67. Bromophenol blue (BPB)
A) Is not the most commonly employed tracking dye
B) Can bind with proteins weakly and give purple colour
C) Is a large molecule
D) Is negatively charged above pH 4.6 and hence moves towards the anode***
E) Moves slower than most proteins and nucleic acids
68. To isolate RNA from samples, the most common method is
A) Guanidinium thiocyanate-phenol-chloroform extraction***
B) Guanidinium thiocyanate-methyl alcohol-chloroform extraction
C) Guanidinium thiocyanate-phenol-iodoform extraction
D) Guanidinium cobalamine-phenol-chloroform extraction
E) None of the above
69. In a hot-start PCR
A) The initial temp is 94–96 °C for 1–9 minutes***
B) The initial temp is 70-78 °C for 15–19 minutes
C) The annealing temp is 94–96 °C for 1–9 minutes
D) The elongation temp is set at 99 °C
E) None of the above
70. The size(s) of PCR products is determined by comparison with
A) Size of the primer used
B) A RNA ladder
C) A DNA ladder***
D) Amount of Taq polymerase used
E) Amount of endonuclease used

14. 71. PCR permits all of the following, except
A) Early diagnosis of malignant diseases such as leukemia and lymphomas
B) Identification of non-cultivatable or slow-growing microorganisms such as mycobacteria
C) Identification of viruses from tissue culture assays
D) Genetic fingerprinting
E) Detection of prions***
72. Variations on the basic PCR technique include all of the following, except
A) Allele-specific PCR
B) Allele-non-specific PCR***
C) Hot-start PCR
D) Multiplex PCR
E) Nested PCR
73. Regarding plasmids, all of the following are true, except
A) Very versatile, easily manipulated vectors
B) Usually linear, single stranded and uncoiled***
C) Occur widely in nature and in most bacterial species
D) Vary considerably in size, from a thousand base pairs to several hundred kilo bases
E) Those used as gene cloning vectors are usually small (2-5 Kb)
74. Stocks of nucleotides for PCR (or other procedure) are nearly always
A) dNTPs (deoxynucleotides)***
B) dNTPs (deoxynucleosides)
C) ATP
D) ADP
E) Primers
75. Rules for working in a PCR lab are
A) Wear gloves
B) Use plugged tips
C) Don't use too much template DNA
D) Titrate calcium***
E) Work clean