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Science and Technology for AP Exams · Chapter 5

Biotechnology, Nanotechnology and Genetic Engineering

What to remember

  • Biotechnology uses living organisms or their parts to make useful products. Genetic engineering changes the DNA of an organism by cutting and joining genes using enzymes.
  • Nanotechnology works at the scale of 1 to 100 nanometres. At this size materials show new properties, which are used in medicine, electronics, water cleaning and farming.
  • New technologies need rules. India regulates GM crops through biosafety bodies, and ethical questions arise on cloning, stem cells and gene editing.

DNA and genes

DNA (deoxyribonucleic acid) carries the genetic information of living things. It is a double helix made of nucleotides. Each nucleotide has a sugar (deoxyribose), a phosphate and one of four bases: adenine (A), thymine (T), guanine (G) and cytosine (C). A pairs with T, and G pairs with C. RNA has ribose sugar and uracil (U) instead of thymine; it is usually single stranded.

A gene is a segment of DNA that codes for a protein. The DNA is copied in a process called replication. A gene is read into messenger RNA in transcription, and the message is used to build a protein in translation. DNA is packed in chromosomes. Humans have 23 pairs of chromosomes. The Human Genome Project mapped the full set of human genes and was completed in the early 2000s.

Recombinant DNA technology

Recombinant DNA technology (genetic engineering) joins DNA from two different sources. The main tools are:

  • Restriction enzymes (molecular scissors) cut DNA at specific sequences.
  • DNA ligase (molecular glue) joins DNA pieces.
  • Vectors such as plasmids carry the gene into a host cell. Plasmids are small circular DNA found in bacteria.
  • Host cells such as the bacterium *E. coli* multiply the gene.
  • PCR (polymerase chain reaction) makes millions of copies of a DNA piece quickly.

Steps are: isolate the gene, cut it and the vector with the same enzyme, join them, put the new DNA into the host, and select the cells that carry it. Human insulin was made by this method using bacteria. Other products are growth hormone, hepatitis B vaccine and clotting factors. Gene therapy tries to treat genetic disease by supplying a working gene. CRISPR-Cas9 is a gene editing tool that cuts DNA at a chosen spot, and it is more precise and cheaper than older methods.

GM crops and biosafety

A genetically modified (GM) crop carries a gene from another organism. Bt cotton contains a gene from the soil bacterium *Bacillus thuringiensis*; the gene makes a protein toxic to the bollworm pest. Bt cotton is the only GM crop approved for commercial farming in India. Other examples in the world are herbicide-tolerant crops and Golden Rice, which has beta-carotene to prevent vitamin A deficiency.

Benefits claimed are higher yield, less pesticide and better nutrition. Concerns are effects on health, on other insects, gene flow to wild relatives, seed company control and loss of biodiversity. In India the Genetic Engineering Appraisal Committee (GEAC) under the Ministry of Environment, Forest and Climate Change approves GM organisms. The Cartagena Protocol is the international agreement on safe handling of living modified organisms. India follows rules under the Environment Protection Act for GM products, and food rules are under the Food Safety and Standards Authority of India.

Tissue culture, stem cells and vaccines

Tissue culture grows whole plants from a small piece of plant tissue in a sterile medium with nutrients and hormones. It is based on totipotency, the ability of a plant cell to grow into a full plant. It is used for fast multiplication of banana, orchids and sugarcane, and to produce disease-free plants.

Stem cells are unspecialised cells that can become other cell types. Embryonic stem cells can form any cell type. Adult stem cells (for example in bone marrow) form limited types. Bone marrow transplant is a widely used stem cell treatment. Cord blood banking stores stem cells from the umbilical cord.

Vaccine typeIdeaExample
Live attenuatedWeakened germMeasles, oral polio
InactivatedKilled germInjected polio
Subunit/recombinantA protein made by genetic engineeringHepatitis B
mRNAGives instructions to make a proteinSome COVID-19 vaccines

Biofuels

Biofuels are made from biological material. Bioethanol comes from sugarcane molasses, grains or crop waste and is blended with petrol. Biodiesel is made from vegetable oils or used cooking oil by a chemical reaction called transesterification. Jatropha is a plant source of oil. India's national policy on biofuels promotes ethanol blending and use of non-food feedstock to save foreign exchange and cut emissions. Advanced biofuels use agricultural waste (second generation) or algae (third generation).

Nanotechnology

One nanometre is one billionth of a metre. A human hair is about tens of thousands of nanometres wide. At nano scale a material has a large surface area compared with its volume, so its colour, strength and chemical activity change.

MaterialSpecial use
Carbon nanotubesVery strong, conduct electricity; used in composites and electronics
GrapheneOne-atom-thick carbon sheet; strong and highly conductive
Silver nanoparticlesKill germs; used in coatings and water filters
Quantum dotsDisplay colour and imaging
Titanium dioxide nanoparticlesSunscreens and self-cleaning surfaces

Applications: targeted drug delivery to cancer cells, better diagnostics, lighter and stronger materials, water purification, smart packaging, efficient solar cells and sensors. Nano-fertilisers are also used in farming. Risks include possible toxicity and environmental build-up of nanoparticles. India runs the Nano Mission under the Department of Science and Technology.

Bioethics and regulation

Bioethics asks what we should and should not do with biological technology. Main issues are: human cloning (generally banned for reproduction), designer babies and germline editing, privacy of genetic data, ownership of genetic resources, consent in clinical trials, and animal welfare. The Convention on Biological Diversity and the Nagoya Protocol deal with access to genetic resources and sharing of benefits with local communities. In India, the Biological Diversity Act and the National Biodiversity Authority handle this. The Department of Biotechnology, under the Ministry of Science and Technology, promotes biotechnology research. The Indian Council of Medical Research frames ethical rules for research on humans.

Other uses of biotechnology

Industrial biotechnology uses microbes and enzymes to make products. Yeast ferments sugar to give alcohol, and *Lactobacillus* turns milk into curd. Enzymes such as amylase and protease are used in detergents, food and leather. Bioremediation uses microbes to clean oil spills and toxic waste. Biofertilisers such as Rhizobium, Azotobacter and blue-green algae add nitrogen to soil, and biopesticides reduce chemical use. DNA fingerprinting compares unique patterns in DNA and is used in crime investigation, paternity tests and identifying disaster victims. Transgenic animals carry a foreign gene and are used to study disease and to make medicines. Biosensors and diagnostic kits based on antibodies help detect disease early.

Genetic disorders and testing

Some diseases pass through genes. Haemophilia is a bleeding disorder, sickle cell anaemia changes the shape of red blood cells, and thalassaemia reduces haemoglobin. Down syndrome is caused by an extra copy of chromosome 21. Genetic counselling and screening help families understand risk. Genome sequencing reads the full DNA of a person or organism, and its cost has fallen sharply, so it is used more in medicine and in tracking disease outbreaks. Laws protect patients from misuse of such data, and tests that reveal the sex of a foetus are banned in India under the PCPNDT Act.

Exam traps

  • Restriction enzymes cut DNA; ligase joins it.
  • DNA has thymine; RNA has uracil.
  • Plasmids are circular DNA in bacteria, not chromosomes.
  • Bt cotton is the only GM crop commercially approved in India for farming; Bt brinjal and others are not.
  • Totipotency is for tissue culture; embryonic stem cells are pluripotent.
  • Bioethanol is mixed with petrol; biodiesel replaces or mixes with diesel.
  • CRISPR edits DNA; PCR copies DNA.
  • GEAC is a regulator of GM organisms; it is not a research institute.

One-liners

  • DNA bases pair as A with T and G with C.
  • Human insulin was produced in bacteria by genetic engineering.
  • Plasmids are used as vectors.
  • PCR makes many copies of DNA.
  • Bt toxin kills the bollworm.
  • Golden Rice has beta-carotene.
  • GEAC approves GM organisms in India.
  • Tissue culture grows plants in a sterile medium.
  • Bone marrow transplant is a stem cell treatment.
  • Biodiesel can be made from non-edible oils.
  • One nanometre equals one billionth of a metre.
  • India has a Nano Mission under the Department of Science and Technology.

Practice questions

  1. Which base is found in RNA but not in DNA?

    1. Adenine
    2. Uracil
    3. Thymine
    4. Guanine
    Answer

    B. Uracil

    RNA has uracil in place of thymine.

  2. In DNA, adenine always pairs with

    1. Thymine
    2. Cytosine
    3. Uracil
    4. Guanine
    Answer

    A. Thymine

    A pairs with T and G pairs with C.

  3. Which enzyme is called a molecular scissor in genetic engineering?

    1. DNA polymerase
    2. DNA ligase
    3. Restriction enzyme
    4. Amylase
    Answer

    C. Restriction enzyme

    Restriction enzymes cut DNA at specific sequences.

  4. DNA ligase is used to

    1. Cut DNA
    2. Copy RNA
    3. Break proteins
    4. Join DNA fragments
    Answer

    D. Join DNA fragments

    Ligase seals DNA pieces together like glue.

  5. Small circular DNA of bacteria used as a vector is called a

    1. Ribosome
    2. Plasmid
    3. Nucleus
    4. Chromosome
    Answer

    B. Plasmid

    Plasmids carry foreign genes into host cells.

  6. Which technique makes millions of copies of a DNA segment?

    1. PCR
    2. Fermentation
    3. Electrophoresis
    4. Chromatography
    Answer

    A. PCR

    Polymerase chain reaction amplifies DNA.

  7. Human insulin for diabetes is commercially made using

    1. Genetically engineered bacteria
    2. Pig kidneys only
    3. Plant roots
    4. Radiation
    Answer

    A. Genetically engineered bacteria

    The human insulin gene is put in bacteria such as E. coli.

  8. Bt cotton contains a gene from which organism?

    1. Yeast
    2. Rhizobium
    3. Bacillus thuringiensis
    4. Escherichia coli
    Answer

    C. Bacillus thuringiensis

    The Bt gene makes a protein toxic to bollworm.

  9. Which GM crop is approved for commercial cultivation in India?

    1. Golden Rice
    2. Bt brinjal
    3. GM mustard in all states
    4. Bt cotton
    Answer

    D. Bt cotton

    Bt cotton is the only GM crop commercially grown in India.

  10. Which committee approves GM organisms in India?

    1. UGC
    2. ICMR
    3. Genetic Engineering Appraisal Committee
    4. NITI Aayog
    Answer

    C. Genetic Engineering Appraisal Committee

    GEAC works under the Environment Ministry.

  11. Golden Rice is enriched with

    1. Beta-carotene
    2. Iron only
    3. Vitamin C
    4. Calcium
    Answer

    A. Beta-carotene

    It was designed to help prevent vitamin A deficiency.

  12. The ability of a plant cell to grow into a complete plant is called

    1. Mutation
    2. Totipotency
    3. Apoptosis
    4. Transcription
    Answer

    B. Totipotency

    Totipotency is the basis of plant tissue culture.

  13. Which is a stem cell treatment widely used in medicine?

    1. Vaccination
    2. X-ray
    3. Blood test
    4. Bone marrow transplant
    Answer

    D. Bone marrow transplant

    Bone marrow contains blood-forming stem cells.

  14. Bioethanol blended with petrol is mainly produced from

    1. Crude oil
    2. Natural gas
    3. Sugarcane molasses and grains
    4. Coal tar
    Answer

    C. Sugarcane molasses and grains

    Ethanol is a fermentation product of sugar and starch crops.

  15. Biodiesel is made from vegetable oils by a process called

    1. Photosynthesis
    2. Hydrolysis of salts
    3. Distillation of crude oil
    4. Transesterification
    Answer

    D. Transesterification

    Oil reacts with alcohol in transesterification to give biodiesel.

  16. One nanometre is equal to

    1. One millionth of a metre
    2. One billionth of a metre
    3. One trillionth of a metre
    4. One thousandth of a metre
    Answer

    B. One billionth of a metre

    1 nm = 10^-9 m.

  17. Which nanomaterial is a single layer of carbon atoms?

    1. Graphene
    2. Quantum dot
    3. Silver nanoparticle
    4. Fullerene
    Answer

    A. Graphene

    Graphene is a one-atom-thick sheet of carbon.

  18. Silver nanoparticles are used in water filters because they

    1. Add colour
    2. Increase pH
    3. Make water sweet
    4. Kill germs
    Answer

    D. Kill germs

    Silver has antimicrobial action.

  19. The Nano Mission in India is run under the

    1. Ministry of Defence
    2. Ministry of Finance
    3. Department of Science and Technology
    4. Ministry of Railways
    Answer

    C. Department of Science and Technology

    The Nano Mission is a programme of the DST.

  20. The tool called CRISPR-Cas9 is used for

    1. Measuring blood pressure
    2. Gene editing
    3. Growing tissue
    4. Making biofuel
    Answer

    B. Gene editing

    CRISPR-Cas9 cuts DNA at a chosen site to edit genes.

  21. Which vaccine type uses a weakened live germ?

    1. mRNA vaccine
    2. Subunit vaccine
    3. Live attenuated vaccine
    4. Toxoid vaccine
    Answer

    C. Live attenuated vaccine

    Live attenuated vaccines use a weakened form of the germ.

  22. The hepatitis B vaccine is an example of a

    1. Live attenuated vaccine
    2. Killed whole-germ vaccine
    3. Antibiotic
    4. Recombinant subunit vaccine
    Answer

    D. Recombinant subunit vaccine

    It uses a viral protein made by genetic engineering.

  23. The international agreement on safe handling of living modified organisms is the

    1. Cartagena Protocol
    2. Kyoto Protocol
    3. Ramsar Convention
    4. Montreal Protocol
    Answer

    A. Cartagena Protocol

    The Cartagena Protocol on Biosafety deals with LMOs.

  24. Access to genetic resources and benefit sharing is the subject of the

    1. Stockholm Convention
    2. Nagoya Protocol
    3. Basel Convention
    4. Vienna Convention
    Answer

    B. Nagoya Protocol

    The Nagoya Protocol deals with access and benefit sharing.

  25. A scientist wants to quickly produce thousands of disease-free banana plants. The best method is

    1. Cross-breeding
    2. Tissue culture
    3. Grafting only
    4. Seed storage
    Answer

    B. Tissue culture

    Tissue culture gives rapid, disease-free clones.

  26. A company wants an insect-resistant crop. Which approach fits?

    1. Use nanotube fibres
    2. Increase irrigation
    3. Add a gene for insect toxin
    4. Remove chlorophyll
    Answer

    C. Add a gene for insect toxin

    Transferring a toxin gene such as Bt gives insect resistance.

  27. Nanoparticle drug delivery to tumours is useful because it

    1. Delivers medicine to specific cells
    2. Raises body temperature
    3. Needs no testing
    4. Replaces all surgery
    Answer

    A. Delivers medicine to specific cells

    Targeted delivery reduces side effects.

  28. Why do nanomaterials show different properties from bulk material?

    1. They have no atoms
    2. They are always magnetic
    3. They are always liquid
    4. They have large surface area for their volume
    Answer

    D. They have large surface area for their volume

    At nano scale surface effects dominate.

  29. The process of building a protein from an mRNA message is called

    1. Translation
    2. Transcription
    3. Mutation
    4. Replication
    Answer

    A. Translation

    Translation reads mRNA to make protein; transcription makes mRNA from DNA.

  30. Consider the statements: 1. Restriction enzymes cut DNA. 2. DNA ligase joins DNA.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both statements are correct.

  31. Consider the statements: 1. RNA contains thymine. 2. DNA contains deoxyribose sugar.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    RNA has uracil; DNA has deoxyribose.

  32. Consider the statements: 1. Bt cotton is the only GM crop commercially approved in India. 2. GM crops are approved by GEAC.

    1. 1 only
    2. 2 only
    3. Neither 1 nor 2
    4. Both 1 and 2
    Answer

    D. Both 1 and 2

    Both statements are correct.

  33. Consider the statements: 1. PCR makes copies of DNA. 2. CRISPR is used to make copies of DNA.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    CRISPR edits DNA; PCR copies it.

  34. Consider the statements: 1. Embryonic stem cells can form many cell types. 2. Adult stem cells can form any cell type in the body.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Adult stem cells form limited cell types.

  35. Consider the statements: 1. Bioethanol is blended with petrol. 2. Biodiesel can be made from used cooking oil.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both statements are correct.

  36. Consider the statements: 1. Carbon nanotubes conduct electricity. 2. Nanotechnology deals with sizes of about 1 to 100 nanometres.

    1. 1 only
    2. 2 only
    3. Neither 1 nor 2
    4. Both 1 and 2
    Answer

    D. Both 1 and 2

    Both statements are correct.

  37. Consider the statements: 1. Plasmids are found in bacteria. 2. Plasmids are used as vectors.

    1. Both 1 and 2
    2. 1 only
    3. 2 only
    4. Neither 1 nor 2
    Answer

    A. Both 1 and 2

    Both statements are correct.

  38. Match the item with its use: 1. Golden Rice - A. Vitamin A 2. Bt cotton - B. Pest resistance 3. Tissue culture - C. Plant multiplication

    1. 1-A, 2-C, 3-B
    2. 1-A, 2-B, 3-C
    3. 1-B, 2-A, 3-C
    4. 1-C, 2-B, 3-A
    Answer

    B. 1-A, 2-B, 3-C

    Golden Rice gives beta-carotene, Bt gives pest resistance, tissue culture multiplies plants.

  39. Match the tool with its function: 1. Ligase - A. Cuts DNA 2. Restriction enzyme - B. Joins DNA 3. PCR - C. Copies DNA

    1. 1-C, 2-B, 3-A
    2. 1-B, 2-A, 3-C
    3. 1-A, 2-B, 3-C
    4. 1-B, 2-C, 3-A
    Answer

    B. 1-B, 2-A, 3-C

    Ligase joins, restriction enzymes cut, PCR copies.

  40. Match the nanomaterial with its use: 1. Quantum dots - A. Display colours 2. Silver nanoparticles - B. Germ killing 3. Titanium dioxide - C. Sunscreen

    1. 1-B, 2-A, 3-C
    2. 1-C, 2-A, 3-B
    3. 1-A, 2-C, 3-B
    4. 1-A, 2-B, 3-C
    Answer

    D. 1-A, 2-B, 3-C

    Each pair is correct in option B.

  41. Match the vaccine with its type: 1. Oral polio - A. Inactivated 2. Injected polio - B. Live attenuated 3. Hepatitis B - C. Recombinant

    1. 1-C, 2-A, 3-B
    2. 1-B, 2-C, 3-A
    3. 1-B, 2-A, 3-C
    4. 1-A, 2-B, 3-C
    Answer

    C. 1-B, 2-A, 3-C

    Oral polio is live attenuated, injected polio is inactivated, hepatitis B is recombinant.

  42. Reproductive human cloning is generally

    1. Required by law
    2. Banned by ethical guidelines
    3. Used to cure diabetes
    4. Used in all hospitals
    Answer

    B. Banned by ethical guidelines

    It raises serious ethical issues and is generally prohibited.

  43. Which of these is a second-generation biofuel feedstock?

    1. Soybean oil
    2. Corn grain
    3. Sugarcane juice
    4. Agricultural waste
    Answer

    D. Agricultural waste

    Second-generation biofuels use non-food biomass like crop residue.

  44. Genetic information in the cell is stored in

    1. Starch
    2. Water
    3. DNA
    4. Lipids
    Answer

    C. DNA

    DNA carries the genetic code.

  45. The Biological Diversity Act in India is implemented with the help of the

    1. Law Commission
    2. Election Commission
    3. National Biodiversity Authority
    4. Reserve Bank of India
    Answer

    C. National Biodiversity Authority

    The NBA regulates access to biological resources.

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