Biotechnology

Chapter 15: Biotechnology

1. DNA Cloning

  • What It Is: Creating copies of DNA fragments by inserting them into vectors (like plasmids).

  • Process:

    1. Restriction Enzymes: These "molecular scissors" cut DNA at specific sequences, leaving sticky ends.

    2. Recombinant DNA: Sticky ends of DNA fragments pair up, and DNA ligase joins them into a single strand.

    3. Cloning Vector: A plasmid or viral DNA that carries the recombinant DNA into host cells (like bacteria).

    4. Host Cell Replication: The host cell divides, copying the inserted DNA, producing large amounts of the target sequence.

2. Polymerase Chain Reaction (PCR)

  • Purpose: Amplifies specific DNA segments.

  • Steps:

    1. Denaturation: Heat separates DNA strands.

    2. Annealing: Primers attach to target sequences.

    3. Extension: Taq polymerase synthesizes new DNA strands.

  • Uses: Crime scene analysis, diagnosing genetic disorders, and studying ancient DNA.

3. DNA Sequencing

  • Sanger Sequencing: Uses dideoxynucleotides to terminate replication at specific bases. Electrophoresis separates these fragments, revealing the DNA sequence.

  • Application: Determines the nucleotide order in a DNA molecule, helping in genome studies and medical diagnostics.

4. Gene Therapy

  • What It Is: Fixing defective genes by introducing functional copies into cells.

  • Tools: Viral vectors carry the therapeutic gene into target cells.

  • Applications: Treatment of genetic disorders like sickle-cell anemia and cystic fibrosis.

Chapter 19: Viruses, Bacteria, and Archaea

1. Viruses

  • Structure:

    • Core of DNA or RNA.

    • Protein coat (capsid).

    • Some have a lipid envelope derived from host cells.

  • Replication Cycles:

    • Lytic: Virus hijacks the host cell to produce new virions, causing cell lysis.

    • Lysogenic: Viral DNA integrates into the host genome and remains dormant until activated.

2. Bacteria

  • Prokaryotic Features:

    • No nucleus or membrane-bound organelles.

    • Single circular chromosome and plasmids.

    • Asexual reproduction via binary fission.

  • Gene Transfer:

    • Transformation: Uptake of DNA from the environment.

    • Transduction: Viral transfer of bacterial genes.

    • Conjugation: Direct transfer of DNA between bacteria using a pilus.

3. Archaea

  • Unique Traits:

    • Cell walls without peptidoglycan.

    • Found in extreme environments (thermophiles, halophiles).

    • Genetically closer to eukaryotes than bacteria.

Chapter 20: Protists

1. Flagellated Protozoans

  • Examples:

    • Giardia: Causes diarrhea; adapted to low-oxygen environments.

    • Trypanosoma: Causes African sleeping sickness; transmitted by tsetse flies.

2. Alveolates

  • Dinoflagellates: Photosynthetic and some bioluminescent. Can cause harmful algal blooms (red tides).

  • Apicomplexans: Parasites like Plasmodium, causing malaria, with a complex life cycle involving mosquitoes and humans.

3. Amoebozoans

  • Examples:

    • Amoebas: Use pseudopods for movement and feeding.

    • Slime Molds: Transition between single and multicellular stages.

Chapter 21: Plant Evolution

1. Adaptations to Land

  • Cuticle: Waxy layer preventing water loss.

  • Stomata: Open/close to balance water retention and gas exchange.

  • Vascular Tissue:

    • Xylem: Transports water and minerals.

    • Phloem: Transports sugars.

2. Plant Life Cycles

  • Alternation of Generations:

    • Gametophyte (haploid): Produces gametes.

    • Sporophyte (diploid): Produces spores.

3. Major Groups

  • Bryophytes: Nonvascular; gametophyte-dominant (e.g., mosses).

  • Seedless Vascular Plants: Sporophyte-dominant; disperse via spores (e.g., ferns).

  • Gymnosperms: Naked seeds on cones (e.g., conifers).

  • Angiosperms: Flowers and fruits with enclosed seeds (e.g., flowering plants).