Biology

• Biology


  A branch of science that deals with the study of living organisms
• Categories of living organisms

  • Plants
  • Animals
  • Microorganisms
• Main branches of biology

  • Botany (study of plants)
  • Zoology (study of animals)
  • Microbiology (study of microorganisms)
• Biotechnology

  • Study of techniques for application of biological processes
  • Used in industries like medicine and agriculture
• Ecology


  • Study of living organisms and their environment
  • Examines interactions between organisms and their environment
• Genetics


  • Study of inheritance and variations
• Entomology


  • Study of insects
• Parasitology


  • Study of parasites
• Embryology


  • Study of development of animals
• Physiology


  • Study of body functions
• It is mostly used in schools
• Light microscope


  It uses light to illuminate the specimen being viewed
• Eye-piece


  • Contains lens for magnifying object
• Bodies of multicellular organisms are made up of microscopic units called cells
• Cells carry out various processes and functions in an organism
• The cell is the basic unit of life
• Magnifying instruments


  • Light microscope
  • Electron microscope
• Light microscope


  • Coarse adjustment knob used to raise or lower the body tube to bring object into focus
  • Fine adjustment knob used to raise or lower the body tube over a small distance to produce a sharp image
  • Diaphragm is an aperture that can be adjusted to regulate the amount of light entering the condenser
  • Condenser is a system of lenses that focuses and concentrates light rays onto the object
  • Objective lens contains lenses that magnify the object
  • Revolving nose-piece used for changing from one objective lens to another
• Using a light microscope

  1. Place specimen slide on stage

  2. Adjust diaphragm and mirror to control light

  3. Rotate revolving nose-piece to select objective lens

  4. Use coarse and fine adjustment knobs to focus
• Caring for a microscope

  • Hold the arm with one hand and the base with the other when carrying
  • Avoid placing at edge of bench, keep at safe distance
  • Avoid touching lenses and mirror with fingers
  • Clean lenses with special soft cloth or tissue moistened with ethanol
  • Oil moveable parts occasionally
  • Turn low objective lens into position before and after use
  • Store in dry place
• To calculate magnification, multiply the magnification of the eyepiece by the magnification of the objective lens
• Morphology


  • Study of external structure of organisms
• The nucleus is the control centre of the cell, containing DNA.
• Anatomy


  • Study of internal structure of organisms
• Cytology


  • Study of cells
• Ichthyology


  • Study of fishes
• Chemicals of life


  Chemical compounds which constitute living organisms
• Chemical compounds


  Made up of elements
• Most common elements in living organisms

  • Hydrogen (H)
  • Carbon (C)
  • Oxygen (O)
  • Nitrogen (N)
• Organic compounds


  Carbon compounds which are complex in nature
• Organic compounds


  • Readily dissolve in water
  • Form crystals (crystallisable)
  • Are reducing sugars
• Monosaccharides


  Reduce blue (1) sulphate in Benedicts's solution to insoluble copper (1) oxide which is brown
• Inorganic compounds


  Compounds which do not contain carbon and are less complex in nature
• Inorganic compounds


  • Water
  • Mineral salts
• Carbohydrates


  Made of elements carbon, hydrogen and oxygen in the ratio of 1:2:1
• Classes of carbohydrates


  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides


  Simple sugars, examples include glucose, fructose and galactose
• Monosaccharides


  The basic units of carbohydrates
• Monosaccharides


  Their general formula is CHO
• Properties of monosaccharides


  • They are sweet tasting