RT

HB Unit 7_ Biotechnology Notes (2025)

GMO

  • Definition: Genetically Modified Organisms (GMO) are organisms whose DNA has been altered to contain genes not normally found in them.

Biotechnology

  • Definition: Biotechnology is the use of organisms or their components to produce products or processes.

  • Examples:

    • Yeast in bread and alcohol production

    • Beneficial bacteria like penicillin that kill harmful organisms

    • Plant and animal cloning

    • Focus on DNA technology over the last 40 years

Biotech Advancements

  • Craig Venter:

    • 2008: "On the verge of creating synthetic life"

    • 2010: "Watch me unveil synthetic life"

  • Sebastian Kraves (2016)

    • Announced the era of personal DNA testing

  • Jennifer Doudna (2015)

    • Discussed how CRISPR technology enables DNA editing

DNA Technology

  • Definition: Refers to the sequencing, analysis, and manipulation of DNA.

  • Common DNA technologies:

    • DNA Sequencing

    • Polymerase Chain Reaction (PCR)

    • DNA Cloning

    • Gel Electrophoresis

Manipulating DNA

  • Biotechnology Basics:

    • Involves cutting out specific DNA pieces using restriction enzymes (enzymes that act as molecular scissors).

    • Restriction Enzymes:

      • Recognize and cut at specific nucleotide sequences

      • Hundreds exist, each recognizing different sequences

Applications of Restriction Enzymes

  • Originally for bacterial defense against viruses

  • Uses:

    • Forensics (DNA fingerprints)

    • Cloning (isolating desired sequences)

    • Genomics (studying complete genomes)

Polymerase Chain Reactions (PCR)

  • Purpose: Technique to amplify small DNA samples for study

  • Process:

    1. Heat DNA to separate strands, then cool.

    2. Primers attach to initiate replication.

    3. DNA Polymerase adds nucleotides to the strands.

    4. This cycle is repeated multiple times, doubling the number of strands each time (2^n, n = number of cycles).

Gel Electrophoresis

  • Definition: Technique to separate DNA fragments by size using an electric field.

  • Uses:

    • DNA fingerprinting

    • Paternity tests

    • Organism identification

    • Molecular cloning

    • And more

Steps of Gel Electrophoresis

  1. DNA fragments cut by restriction enzymes are loaded into the gel.

  2. An electric current separates them (+ side attracts - charged DNA).

  3. Larger molecules move slower; smaller fragments travel further.

DNA Fingerprinting

  • Purpose: Identifies individuals at a molecular level and shows familial relationships.

  • Method: DNA cut with restriction enzymes, run through gel to separate by size.

  • Key Fact: No two individuals have the same DNA fingerprint.

Uses of DNA Fingerprinting

  1. Crime scene investigation: identify suspects or prove innocence.

  2. Paternity testing: confirm parentage.

  3. Studying biodiversity within species.

  4. Genetically engineered crops.

Genetic Engineering

  • Definition: Changing an organism's DNA to provide new traits using recombinant DNA.

  • Recombinant DNA: DNA from multiple organisms (e.g., mouse + firefly glow gene).

  • Transgenic Organisms: Organisms with inserted genes from other organisms.

  • Plasmids: Circular DNA in bacteria used to carry foreign DNA into cells.

Bacteria and Genetic Engineering

  • Why Bacteria?

    • Replicate quickly and possess plasmids that replicate independently.

    • Vectors: plasmids or viruses for gene insertion.

Benefits of Transgenic Bacteria

  • Example: Bacteria produce human insulin, resulting in:

    1. Higher hormone quantities at lower costs.

    2. Non-allergic human proteins.

Products of Modern Biotechnology

  • Common Recombinant DNA Products:

    • Human insulin, Human growth hormone, Epidermal growth factor, IL-2, BGH, Cellulase, Taxol, Erythropoietin, Factor VIII

Applications of Genetic Engineering

  1. Plants: Engineered for frost, herbicide, disease, and insect resistance.

    • Developing plants for pharmaceuticals ("pharming").

  2. Animals: Genetically modified animals for disease research (e.g., Oncomouse).

  3. Vaccines: Creation of vaccines using recombinant DNA.

Genetic Engineering Controversies

  • Possible reproduction of engineered organisms with non-engineered ones.

  • Concerns over impact on pollinators and ecosystems.

  • Potential long-term health effects.

  • Ethical questions around designer humans.

Genetic Engineering: GMOs

  • Definition: Organisms with DNA altered to include foreign DNA.

  • Most commonly found in plants, especially engineered foods.

  • Example: Golden rice enriched with Vitamin A to combat malnutrition.

Comparing GMOs to Traditional Genetics

  • Selective Breeding:

    • Slow, imprecise modifications of naturally occurring genes.

  • GMOs:

    • Fast, precise introduction of genes that wouldn't naturally occur.

Are GMOs Safe?

  1. GMO safety concerns over long-term health impacts (e.g., cancer, allergies).

  2. Specific cases of GMOs causing respiratory or GI issues in nearby populations.

  3. Ethical implications of food patenting by large corporations like Monsanto.

Cloning

  • Definition: Creating a genetically identical copy of a gene or organism.

  • Steps:

    1. Remove nucleus from an egg.

    2. Insert nucleus from original organism.

    3. Stimulate egg to divide.

    4. Insert into a surrogate.

Cloning Benefits and Controversies

  • Benefits: Identical organ transplants, repopulating endangered species.

  • Controversies:

    • Low success rates in mammals; health problems in clones.

    • Ecological concerns over biodiversity loss.

    • Ethical concerns, including eugenics and organ farming.

Human Genome Project

  • Genomics: Study of organism genomes for various applications.

  • Proteomics: Study of cellular proteins for drug therapy and cell analysis.

Genetic Screening

  • Definition: Testing DNA for risks of genetic disorders.

  • Methods: DNA sampling and gel electrophoresis; applications in diseases like breast cancer and Huntington’s.

Gene Therapy

  • Definition: Replacement or addition of genes to treat diseases.

  • Current Status: Not perfected; ongoing research, particularly for conditions like cancer.

Gene Therapy for Sickle Cell Disease

  1. Collect stem cells.

  2. Correct via gene transfer using viral vectors.

  3. Transplant corrected stem cells back to the patient.