Biotechnology Quiz 1 Quiz InstructionsThis quiz consists of 20 multiple-choice questions.You will be awarded 5 marks for each correct answer. Question 1: In the enzymatic method of DNA sequencing developed by Sanger, why does the addition of a 2',3'-dideoxynucleotide analog block further chain elongation?It lacks a 3'-hydroxyl group required to form the next phosphodiester bond.It prevents the binding of the complementary primer to the single-stranded template.It acts as a competitive inhibitor that denatures the DNA Polymerase-I enzyme.It actively cleaves the template strand at specific purine and pyrimidine residues. Question 2: In a standard Polymerase Chain Reaction (PCR) mixture, which of the following ingredients is added specifically to stabilize the reaction mixture at a pH of 8.4?Gelatin and magnesium chlorideTris buffer with potassium chloride and hydrochloric acidDeoxyribonucleotide triphosphates (dNTPs)Heavy mineral oil Question 3: The thermostable Taq polymerase used in polymerase chain reactions is isolated from which of the following organisms?A thermophilic yeast strainThermus aquaticus, a thermophilic bacteriumBacillus calmette-guerin, a modified bacteriumAutographa californica, a baculovirus Question 4: Assuming 100% amplification efficiency, if a PCR begins with 10^2 molecules of a specific double-stranded DNA template, how many copies of this template will theoretically be present after 20 complete temperature cycles?2.01 x 10^4 copies1.00 x 10^6 copies1.05 x 10^8 copies2.60 x 10^9 copies Question 5: Which capsid protein of the Foot and Mouth Disease (FMD) virus serves as the primary immunogenic site and is used to develop recombinant subunit vaccines?Vp1Vp2Vp3Vp4 Question 6: During the production of a recombinant subunit vaccine for the Foot and Mouth Disease (FMD) virus, why is a yeast cell host preferred over Escherichia coli for cloning the Vp1 gene?Yeast cells are capable of synthesizing glycosylated structural proteins, unlike E. coli.E. coli undergoes high-frequency mutation that inactivates the Vp1 capsid gene.Yeast cells possess the necessary reverse transcriptase to directly replicate viral RNA.Yeast cells prevent the formation of non-immunogenic T-cell memory responses. Question 7: Why are unfused myeloma cells unable to survive in Hypoxanthine-Aminopterin-Thymidine (HAT) medium during the selection phase of monoclonal antibody production?They lack the enzyme Hypoxanthine Guanine Phosphoribosyl Transferase (HGPRT) and aminopterin blocks their de-novo purine synthesis.They are killed directly by high-voltage direct current pulses used during HAT selection.They are highly sensitive to thymidine, which causes contact inhibition and cell senescence.They lack the ability to grow on solid supports and are washed away by the liquid HAT medium. Question 8: In hybridoma technology, why is mineral oil (pristane) injected intraperitoneally into mice before cloning the hybridoma cell line?To block the de-novo synthesis of bases in the mouse's spleen cellsTo induce the formation of an ascitic tumor for large-scale antibody secretionTo prevent the contamination of the hybrid cells with pathogenic virusesTo act as a surfactant that fuses myeloma and B-lymphocytes Question 9: Which of the following correctly describes a 'protein-free' artificial animal cell culture medium?It contains raw serum supplemented with chemically synthesized peptide hormones.It consists of all the typical constituents of serum but completely excludes serum proteins.It contains only small-molecule chemicals and genetically engineered recombinant proteins.It relies entirely on Kreb's ringer bicarbonate solution without any added amino acids. Question 10: Match the following bioreactor/fermentor types (Column I) with their corresponding industrial applications (Column II):Column I:I. External recycle airlift fermentorII. Internal recycle airlift fermentorIII. Tubular tower fermentorIV. Stirred fermentorColumn II:1. Yeast production with oil substrate2. Antibiotic manufacturing3. Yeast/bacterial biomass with methanol substrate4. Beer, wine, and vinegar productionWhich of the following is the correct matching?I-3, II-1, III-4, IV-2I-1, II-3, III-2, IV-4I-3, II-2, III-4, IV-1I-4, II-1, III-3, IV-2 Question 11: Match the following cell staining and analysis tools (Column I) with their physiological application or cell state detected (Column II):Column I:I. Neutral red (NR)II. Trypan blueIII. Cytofluorimetry (FACS)IV. Neubauer chamberColumn II:1. Specifically stains dead cells2. Standard tool used for physical cell counting3. Specifically stains living (viable) cells4. Separates stained dead cells from unstained live cells based on fluorescenceWhich of the following represents the correct combination?I-3, II-1, III-4, IV-2I-1, II-3, III-2, IV-4I-3, II-4, III-1, IV-2I-1, II-4, III-3, IV-2 Question 12: Match the vaccine delivery vehicle/strain (Column I) with its description or specific vaccine usage (Column II) based on the text:Column I:I. Non-virulent Vaccinia virusII. Autographa californica (virus)III. Bordetella bronchisepticaIV. Salmonella typhimuriumColumn II:1. Expresses FMD Vp1 chimeric protein linked to hepatitis B core protein2. Attenuated vaccine vector used as a delivery vehicle3. Clones a 68 Kd outer membrane protein in an avirulent strain4. Extensively used as a vehicle to introduce recombinant epitopes for Rabies and RinderpestWhich of the following is the correct match?I-4, II-1, III-3, IV-2I-2, II-1, III-4, IV-3I-4, II-3, III-1, IV-2I-1, II-4, III-3, IV-2 Question 13: Match the step of the Polymerase Chain Reaction (Column I) with its typical operating temperature and duration in a standard thermal cycler (Column II):Column I:I. Template denaturationII. Primer annealingIII. Primer extension / polymerizationColumn II:1. 55 °C for 20 seconds2. 72 °C for 30 seconds3. 94 °C for 20 secondsWhich of the following is the correct matching?I-3, II-1, III-2I-1, II-3, III-2I-3, II-2, III-1I-2, II-1, III-3 Question 14: Evaluate the following statements regarding the development and characteristics of animal cell lines:I. Primary cell cultures stop dividing when they touch other cells or the container wall due to contact inhibition.II. Diploid cell strains are immortal, grow indefinitely, and undergo no chromosomal rearrangements.III. Heteroploid cells undergo chromosomal rearrangements and deletions, gaining the ability to grow indefinitely in culture.IV. Transformed cell lines lose contact inhibition and no longer require a solid support for growth.Which of the statements are correct?I, II, and III onlyI, III, and IV onlyII and IV onlyI and III only Question 15: Consider the following statements about the properties of the Taq polymerase enzyme used in PCR:I. The enzyme has a molecular weight of 94 KDa and exhibits an optimum temperature of 72 °C.II. It is completely denatured and rendered inactive when heated to 94 °C.III. Higher concentrations of magnesium, dNTPs (4.6 mM), and KCl (200 µM) will inhibit its activity.IV. Low concentrations of conventional protein denaturing agents like urea or ethanol do not denature Taq polymerase.Which of the above statements are correct?I, III, and IV onlyI, II, and III onlyII, III, and IV onlyI and IV only Question 16: Based on the biochemical process of milk curdling described in the text, evaluate the following statements:I. The preformed curd adds the bacterium Lactobacillus cecai to the milk.II. The fermentation of lactose to lactic acid lowers the milk pH from 6.6 to 4.5.III. Casein, the milk protein, has an isoelectric pH of 4.5 at which it precipitates.IV. The curdling process is highly aerobic and requires constant stirring to ensure uniform precipitation.Which of these statements are correct?I, II, and III onlyI, III, and IV onlyII and IV onlyI and III only Question 17: Assertion (A): Established cell lines are routinely cryopreserved in liquid nitrogen at -196 °C.Reason (R): Cryopreservation prevents the permanent loss of cell lines due to contamination, loss of growth, or incubation defects.Both A and R are true, and R is the correct explanation of A.Both A and R are true, but R is not the correct explanation of A.A is true, but R is false.A is false, but R is true. Question 18: Assertion (A): Separated pure Vp1 capsid protein of Foot and Mouth Disease (FMD) virus is much less immunogenic than the intact whole viral particle when injected alone.Reason (R): The isolated pure Vp1 protein fails to generate T-cell memory responses, producing only B-memory cells.Both A and R are true, and R is the correct explanation of A.Both A and R are true, but R is not the correct explanation of A.A is true, but R is false.A is false, but R is true. Question 19: To enhance the immunogenic activity of the isolated FMD viral Vp1 protein, it is mixed with which of the following compounds to form a cage-like immunostimulating complex?Plant glycoside saponin, cholesterol, and phosphatidylcholineUrea, ethanol, and formamidePolyethylene glycol, mineral oil, and gelatinTris-HCl buffer, potassium chloride, and magnesium chloride Question 20: In the development of certain subunit vaccines, antibodies (Ab1) raised against an epitope are used to produce anti-Ab1 antibodies (Ab2). What are these Ab2 antibodies called, which structurally mimic the original antigen's epitope?Monoclonal haptensHeterokaryonsAnti-idiotypesChimeric capsids
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