biology p1

• Topics covered


  • Cells
  • Infection and response
  • Organization
  • Bioenergetics
• Animal and plant cells


  Organelles they both have: Nucleus, Cytoplasm, Mitochondria, Ribosomes, Cell membrane
• Plant cells


  • Vacuole, Cell wall, Chloroplasts
• Eukaryotic cells


  DNA is inside the nucleus
• Prokaryotic cells


  DNA is not in a nucleus, it's in a plasmid
• Mitosis


  1. Chromosomes are copied

  2. Chromosomes line up in the middle

  3. Chromosomes are pulled apart

  4. Daughter nuclei are formed
• Chromosomes in humans


  23 pairs, 46 total
• Meiosis


  1. DNA is copied

  2. Chromosomes swap information

  3. Two daughter nuclei are formed

  4. Four gametes with half the information are produced
• Stem cells


  Become specialized to form different cell types
• Microscopy


  • Magnification = Image size / Object size
  • Nanometers are 1 million times smaller than millimeters
  • Micrometers are 1000 times smaller than millimeters
• Electron microscopes


  Have better resolution than light microscopes, can see organelles
• DNA


  • Made up of 4 bases: A, T, C, G
  • 3 bases code for an amino acid
  • Many amino acids make a protein
  • Many triplets make a gene
• Diffusion


  Particles move from high to low concentration, no energy needed
• Osmosis


  Diffusion of water through a semi-permeable membrane
• Osmosis practical


  1. Cut potato cylinders

  2. Weigh before and after soaking in sucrose solutions

  3. Heavier = water osmosed in, Lighter = water osmosed out, No change = equal concentrations
• Active transport


  Moves substances up concentration gradient, requires energy
• Respiration


  Glucose + Oxygen -> Water + Carbon dioxide, releases energy
• Respiration


  Similar to combustion, a slow "burning" of glucose
• Photosynthesis


  Reverse of respiration, uses light energy to produce glucose
• Photosynthesis rate practical


  1. Use pond weed, measure oxygen bubbles produced

  2. Vary light intensity, control temperature and CO2
• Limiting factor in photosynthesis

  Not the factor on the x-axis, something else is preventing further increase
• Anaerobic respiration


  Glucose -> Lactic acid, less energy released
• Exercise


  Increases heart rate and breathing rate to get more oxygen
• Metabolism


  Sum of all chemical reactions in the body, liver does many
• Pathogens


  • Bacteria
  • Viruses
  • Fungi
  • Protists
• Human defenses


  • Skin
  • Platelets
  • Cilia
  • Mucus
  • Acid
  • White blood cells (phagocytes and lymphocytes)
• Antibodies


  Bind to antigens on pathogens, make them clump together
• Alexander Fleming discovered penicillin, the first antibiotic
• Antibiotics


  Don't kill viruses, need to be used carefully to avoid resistance
• Drug development


  1. Discovery

  2. Development

  3. Trials (animal, human, blind, double-blind)

  4. Manufacture

  5. Review
• Antibiotic testing practical


  1. Prepare agar plate with bacteria

  2. Add antibiotic discs

  3. Measure zones of inhibition
• Drug development process


  1. Test on tissue

  2. Animal trials

  3. Human blind trials

  4. Double blind trials
• Blind trials


  One group given actual drug, other group given placebo to avoid patient bias
• Double blind trials


  Neither patients nor doctors know which group is control to eliminate bias
• Antibiotic testing process


  1. Prepare agar plate

  2. Spread bacteria like E. coli

  3. Place antibiotic discs on lawn

  4. Measure diameter of inhibition zones
• Aseptic technique


  Using Bunsen flame to prevent contamination
• Monoclonal antibody production


  1. Inject mouse with antigen

  2. Extract antibody-producing white blood cells

  3. Fuse with tumor cells to create hybridomas

  4. Clone and harvest antibodies
• Plant defences


  • Cell walls
  • Waxy cuticle
  • Bargain cells
  • Antibacterial chemicals
• Plant mineral deficiencies


  • Nitrate deficiency
  • Magnesium deficiency
• Root hair cell


  Large surface area for water and nutrient absorption