Bio - paper 1

• 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 made of cellulose
  • Chloroplasts
• Eukaryotic cells


  DNA is inside the nucleus
• Prokaryotic cells


  DNA is not in a nucleus, it's in a plasmid (loop or ring)
• 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 have specific jobs
• Microscopy


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


  • Scanning electron microscope
  • Transmission electron microscope
  • Better resolution than light microscopes
• DNA


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


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


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


  1. Cut potato cylinders

  2. Weigh them

  3. Put in sucrose solutions

  4. Weigh again after soaking
• Active transport


  Moving substances up the concentration gradient, requires energy
• Respiration


  1. Glucose + Oxygen -> Water + Carbon Dioxide

  2. Releases energy
• Respiration


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


  Reverse of respiration, uses light energy to produce glucose
• Test for starch


  Add iodine, turns purple
• Photosynthesis rate practical


  1. Use pond weed, measure oxygen bubbles

  2. Vary light intensity

  3. 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 ATP produced
• 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
• Defenses against pathogens


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


  Bind to antigens on pathogens, make them clump together
• Vaccination


  Inject dead/inert version of virus to stimulate antibody production
• Alexander Fleming discovered penicillin, the first antibiotic
• Antibiotics


  Don't kill viruses, must 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

  2. Spread bacteria

  3. Add antibiotic discs

  4. Measure zones of inhibition
• Drug development process


  1. Test on tissue

  2. Animal trials

  3. Human blind trials

  4. Double blind trials

  5. Manufacture and review
• In blind trials, one group gets the actual drug and the other group gets a placebo to avoid patient bias
• In double blind trials, even the doctors don't know which group is the control group to eliminate any bias
• Antibiotic testing procedure


  1. Prepare agar plate

  2. Spread bacteria like E. coli

  3. Use Bunsen flame for aseptic technique

  4. Place antibiotic discs on lawn

  5. Measure diameter of inhibition zones
• Monoclonal antibodies


  Antibodies manufactured by fusing mouse white blood cells with tumor cells to target specific cells or chemicals
• Plant diseases


  • Viral (e.g. tobacco mosaic virus)
  • Fungal (e.g. rose black spots)
  • Mineral deficiencies (e.g. nitrate, magnesium)
• Plant defences


  • Cell walls
  • Waxy cuticle
  • Bargain cells
  • Antibacterial chemicals