Biology

• Enzyme activity and pH


  1. Put a spot of iodine into every well of a spotting tile

  2. Place a bunsen burner on a heatproof mat and a tripod and gauze over the bunsen burner

  3. Put a beaker of water on top of the tripod and heat the water to 35°c

  4. Use a syringe to add 1 cm³ of amylase solution and 1cm³ of buffer solution with a pH of 5 to a boiling tube

  5. Using test tube holders put the tube into the beaker of water and wait 5 mins

  6. Use a different syringe to add 5 cm³ of starch solution to the boiling tube

  7. Immediately mix the contents and start the stopwatch

  8. Use continuous sampling to measure the time taken for amylase to break down starch

  9. Repeat with different pH's
• Microsopy

  1. Add a drop of water to the centre of a clean slide
  2. Cut onion into layers and use tweezers to peel off epidermal tissue
  3. Use tweezers to place epidermal tissue into water
  4. Add a drop of iodine to act as a stain to highlight objects
  5. Place cover slip at angle to avoid bubbles and view your specimen
• Antibiotics

  1.Place paper discs soaked in different antibiotics on agar plate with even covering of bacteria 2.Antibiotics should diffuse into agar jelly 3.Clear area is zone of inhibition Use a control 4.Leave for 48 hours at 25°C 5.Most effective is one with biggest zone of inhibition
• Osmosis Practical

  1. Cut potato into identical cylinders
  2. Get beakers with varying sugars concentrations
  3. Measure the mass of the cylinders
  4. Leave the cylinders in the beakers for 24 hours
  5. Take out and dab gently with paper towel to remove excess water
  6. Measure new mass and calculate % change 
• Rate of Photosynthesis Practical

  1. Place a source of light at a specific distance from pond weed
  2. Leave the pond weed to photosynthesise for a set amount of time
  3. As it photosynthesises oxygen released will collect in a capillary tube
  4. At the end use a syringe to draw gas bubbles up and Measure length with a ruler which is proportional to volume of o2 produced
  5. Repeat with changed distance
• Binary Fission

  1. Circular strands of DNA and plasmids replicate
  2. The cell gets bigger and DNA moves to opposite poles
  3. Cytoplasm begins to divide and cell wall begins to form
  4. Cytoplasm divides and 2 daughter cells form
• The Heart (Right side)


  Vena Cava to right atrium to right ventricle to pulmonary artery to lungs

  DEOXYGENATED BLOOD
• The heart ( LEFT SIDE)

  pulmonary vein to left atrium to left ventricle to aorta to body

  OXYGENATED BLOOD
• Blood Vessels


  • They are designed to carry blood around the body
• Types of blood vessels


  • Arteries
  • Capillaries
  • Veins
• Arteries


  • Carry blood away from the heart
  • Have strong, elastic walls
  • Contain thick layers of muscle and elastic fibres
• Capillaries


  • Very small in size
  • Have thin, permeable walls (only one cell thick)
  • Facilitate exchange of substances between blood and body cells
• Veins


  • Carry blood back to the heart
  • Have larger lumen than arteries
  • Have valves to keep blood flowing in the right direction
  • Have less thick walls than arteries
• Blood needs a good set of tubes to carry it round the body
• Arteries branch into capillaries
• Capillaries eventually join up to form veins
• The blood is at lower pressure in the veins so the walls don't need to be as thick as artery walls
• Veins have a bigger lumen than arteries to help the blood flow despite the lower pressure
• Veins also have valves to help keep the blood flowing in the right direction
• Valves prevent backflow of blood
• Arteries have thick walls that can resist high pressures and elastic fibres that allow them to stretch when under tension.
• Phloem

  • Elongated living cells

  • Pores for Cell sap

  • Dissolved Sugars

  • Both directions

  • Translocation
• Xylem

  • Dead Cells

  • Lignin

  • Water and Mineral ions

  • Transpiration Stream
• Measles

  • Virus

  • Droplets

  • Rash

  • Fever
• HIV

  • Virus

  • Bodily fluids exchanged

  • Flu like
• TMV

  • Virus

  • Mosaic pattern

  • Discolouration
• Malaria

  • Protist

  • Mosquitoes act as vectors

  • Fever
• Salmonella

  • Bacteria

  • Fever

  • Stomach Cramps

  • Vomitting

  • Diarrhoea
• Gonorrhea


  • Bacteria

  • STD

  • pain while urinating

  • Green yellow discharge
• Nitrate deficiency


  Plants use nitrates as a supply of nitrogen, which is needed to make proteins for healthy growth
• How plants absorb nitrates


  1. Plants absorb nitrates in water through their roots

  2. Nitrates are present in high levels in plant fertilisers
• Effects of nitrate deficiency in leaves


  • The amount of chlorophyll reduces
  • Leaves turn a pale green or yellow colour
  • Reduces the plant's ability to photosynthesise and grow properly
  • Reduces the farmers' crop yield
• Fertilisers to increase nitrate levels


  • Chemical fertilisers
  • Natural fertilisers, such as manure
• Magnesium ion deficiency

  Plants use magnesium ions to make chlorophyll in their leaves
• Magnesium ion deficiency


  Limits the plant's photosynthetic ability and compromises plant growth
• Magnesium


  • Is a limiting factor in healthy plant growth
• Pathogens as causes of plant diseases
• Growth of plant solutions