Class 12 Biotechnology and its Applications Mock Test (CBSE)

Topics in Biotechnology and its Applications

• Biotechnological applications in agriculture
• Bt crops and pest resistant plants
• RNA interference
• Biotechnological applications in medicine
• Genetically engineered insulin
• Gene therapy
• Molecular diagnosis
• Transgenic animals
• Ethical issues and biopiracy

Biotechnology and its Applications practice questions with answers

1. Q1Multiple choice·1 mark
   The mechanism of RNA interference (RNAi), used to protect tobacco plants against Meloidogyne incognita, relies on the silencing of a specific mRNA using:

   1. (a)double-stranded RNA (dsRNA)
   2. (b)single-stranded DNA (ssDNA)
   3. (c)ribosomal RNA (rRNA)
   4. (d)transfer RNA (tRNA)
   Show answer and step marks

   1. Correct option: (a)+1

   Answer: (a)
2. Q2Multiple choice·1 mark
   The first clinical gene therapy was given in 1990 to a 4-year-old girl with adenosine deaminase (ADA) deficiency. Such a deficiency primarily affects:

   1. (a)proper functioning of the immune system
   2. (b)digestion of fats in the small intestine
   3. (c)regulation of blood glucose levels
   4. (d)transport of oxygen in red blood cells
   Show answer and step marks

   1. Correct option: (a) proper functioning of the immune system+1

   Answer: (a)
3. Q3Multiple choice·1 mark
   A major challenge in the production of human insulin using recombinant DNA technology was:

   1. (a)obtaining enough pancreas from slaughtered cattle and pigs
   2. (b)preventing allergic reactions caused by animal-derived insulin
   3. (c)getting insulin assembled into a mature, functional form
   4. (d)making the insulin gene replicate within a bacterial plasmid
   Show answer and step marks

   1. Correct option: (c) getting insulin assembled into a mature, functional form. Insulin is made as a prohormone with an extra C-peptide; Eli Lilly made chains A and B separately in E. coli and joined them by disulphide bonds to form mature human insulin.+1

   Answer: (c)
4. Q4Short answer·2 marks
   State the principle on which PCR (Polymerase Chain Reaction) is based. How is this technique useful in molecular diagnosis?
   Show answer and step marks

   1. Principle: Amplification of a DNA sequence of interest using multiple cycles and a thermostable DNA polymerase.+1
   2. Utility in diagnosis: Detection of very low concentrations of pathogens (viruses/bacteria) or mutations in patients even before physical symptoms appear.+1

   Answer: Principle: repeated cycles of denaturation, primer annealing and extension by a thermostable DNA polymerase (Taq) amplify a chosen DNA sequence exponentially. Use: it detects very small amounts of pathogen nucleic acid (e.g. HIV in suspected AIDS patients) or gene mutations (e.g. in suspected cancer patients) early, before symptoms appear.
5. Q5Short answer·2 marks
   Why is early molecular diagnosis considered essential for the effective treatment of diseases? Name two techniques that serve this purpose.
   Show answer and step marks

   1. Conventional methods detect a disease only after symptoms appear, when the pathogen load is already high; molecular diagnosis detects pathogens or mutated genes at very low concentration, so treatment can start early and be effective.+1
   2. First technique, any one of: Polymerase Chain Reaction (PCR), which amplifies very small amounts of a pathogen's nucleic acid; Enzyme Linked Immunosorbent Assay (ELISA), based on antigen-antibody interaction; recombinant DNA technology, e.g. a radioactively labelled DNA/RNA probe hybridising to a mutated gene; or any other valid molecular diagnostic technique.+0.5
   3. Second technique, a different one from the same list.+0.5

   Answer: Conventional methods detect disease only after symptoms appear; molecular diagnosis detects pathogens or mutated genes at very low concentration, allowing early, effective treatment. Any two techniques of: PCR, ELISA, recombinant DNA technology (DNA/RNA probes).

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