Microscopy Fundamentals

Microscopy

• Light microscopy: Uses visible light and lenses to magnify images.
  • Types include brightfield, darkfield, phase-contrast, and fluorescence microscopy.
  • Magnification limited by the wavelength of light.
  • Resolution is the ability to distinguish between two closely spaced points.
• Electron microscopy: Uses a beam of electrons and electromagnetic lenses to magnify images.
  • Higher magnification and resolution than light microscopy.
  • Two main types: transmission electron microscopy (TEM) and scanning electron microscopy (SEM).
    • TEM produces 2D images of internal structures.
    • SEM produces 3D images of surface structures.
• Preparing samples for microscopy:
  • Thin sections often required for TEM.
  • Staining enhances contrast and visibility.
  • Fixation preserves specimen structure.
• Calculating magnification: Magnification = eyepiece magnification × objective lens magnification.
• Calculating actual size of specimens: Actual size = image size / magnification

Organismal Biology

• Organismal biology studies the structure and function of individual organisms.
• Homeostasis: The maintenance of a stable internal environment.
• Biological systems:
  • Nervous system (nerve impulses, hormones, receptors).
  • Endocrine system (hormones, glands, target organs).
  • Digestive system (digestion, absorption, elimination).
  • Respiratory system (gas exchange).
  • Circulatory system (blood transport, circulation).
  • Immune system (fight against pathogens).
• Responding to stimuli: Organisms react to environmental changes.
  • Crucial for maintaining homeostasis.
  • Example: Plants respond to light and gravity.
• Adaptations: Characteristics enhancing survival and reproduction in a specific environment.
  • Structural adaptations (e.g., beak shape in birds).
  • Behavioural adaptations (e.g., migration in birds).

Infection and Response

• Pathogens: Organisms causing disease (e.g., bacteria, viruses, fungi, protists).
• Defense mechanisms: Body's responses to infection.
• Non-specific defenses: First line of defense.
  • Physical barriers (skin, mucous membranes, cilia).
  • Chemical barriers (stomach acidity, lysozyme in tears).
• Specific defenses: Acquired immune response.
  • Lymphocytes: White blood cells for adaptive immunity.
    • B cells produce antibodies targeting specific pathogens.
    • T cells help target and destroy infected cells.
  • Antigens: Molecules on pathogen surfaces triggering immune response.
  • Antibodies: Proteins binding to specific antigens, produced by B cells.
• Immune system response:
  • Inflammation: Body's response to tissue damage (redness, swelling, pain).
  • Antibody production: Immune system creates antibodies to neutralize pathogens.
• Vaccination: Stimulates an immune response without disease.

Biochemistry

• Carbohydrates:
  • Monosaccharides (simple sugars): glucose, fructose, galactose.
  • Disaccharides (double sugars): sucrose, lactose, maltose.
  • Polysaccharides (complex sugars): starch, glycogen, cellulose.
• Lipids:
  • Fats, oils, and waxes.
  • Important for energy storage and membrane structure.
  • Structure includes fatty acids and glycerol.
• Proteins:
  • Composed of amino acids.
  • Diverse functions in the body.
  • Complex structure (primary, secondary, tertiary, quaternary levels).
  • Structure dictates function.
  • Examples: enzymes, hormones, structural proteins (muscle).
• Nucleic acids:
  • DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
  • Carry genetic information.
  • Structure involves nucleotides.
• Enzymes: Biological catalysts, speeding up chemical reactions.
  • Often protein-based.
  • Affected by temperature and pH.
  • Function optimally at specific conditions.
• Metabolic pathways: Sequences of enzyme-controlled biochemical reactions.
• Cellular respiration: Process releasing energy from glucose.

Explore the principles of microscopy, including light and electron microscopy. Understand the different types, preparation of samples, and how to calculate magnification. This quiz will enhance your knowledge about the tools and techniques used in microscopic analysis.