biology

• what do plants convert glucose to?

  starch
• 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

  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. Place antibiotic discs on lawn

  4. Measure diameter of inhibition zones

  5. Identify best antibiotic
• Aseptic technique


  Procedure to ensure no other bacteria enter the dish, using a Bunsen flame to create convection currents
• 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 hybridomas and harvest antibodies
• 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
• Transpiration

  1. Water evaporates from leaves

  2. Causes low pressure in plant

  3. Draws water up xylem
• Transpiration rate is affected by temperature, wind, and humidity
• Food tests

  • Starch - iodine turns purple
  • Fats - ethanol turns cloudy
  • Glucose - Benedict's solution turns orange
  • Proteins - Biuret reagent turns purple
  • Enzymes - specific substrates
• Enzymes

  • Biological catalysts with active sites that bind to specific substrates
  • Can join or break down molecules
  • Affected by temperature and pH
• Enzyme practical

  1. Prepare starch, amylase, and buffer solution

  2. Measure pH effect on amylase activity

  3. Test for starch presence every 20 seconds

  4. Plot results on graph to find optimum pH
• Arteries


  • Thick walls due to high pressure
  • Carry oxygenated blood (except pulmonary artery)
• Veins

  • Thin walls
  • Have valves to prevent backflow
• Capillaries


  Allow gas exchange between blood and cells
• Oxygen and carbon dioxide transport

  • Oxygen binds to hemoglobin in red blood cells
  • Carbon dioxide dissolved in blood plasma
• Non-communicable diseases

  • Atheroma
  • Aneurysm
  • Diabetes
  • Cancer
• Benign vs malignant cancer

  • Benign - mutated cells restricted to one area
  • Malignant - mutated cells spread through body
• Risk factors for non-communicable diseases

  • Diet
  • Smoking
  • Drugs
  • UV light
  • Lack of exercise
  • Carcinogens
• Correlation does not necessarily imply causation - further research is needed to prove causation
• DNA contains genetic information passed from one generation to another.
• The nucleus is the control centre of the cell, containing DNA.
• Homeostasis


  An organism's ability to regulate internal conditions even when external conditions change
• Importance of homeostasis


  • Allows crucial chemical reactions involving enzymes to happen at an Optimum rate
  • Regulates blood glucose concentration, temperature, and water levels
• Nervous system regulation of homeostasis

  1. Receptor detects stimulus

  2. Electrical signal travels to spine through sensory and relay neurons

  3. Signal travels across synapse by neurotransmitter

  4. Signal goes to brain for conscious decision

  5. Signal goes back to effector via relay and motor neurons
• Reflex arc

  Signal bypasses the brain and goes straight through the spine to the effector
• Effectors


  Glands that produce specific chemicals the body needs
• Investigating reaction time

  1. Hold ruler between finger and thumb, drop without warning

  2. Measure distance fallen before caught

  3. Repeat multiple times, take mean average
• Parts of the brain

  • Cerebral cortex - higher level functions
  • Cerebellum - motor skills, movement, balance, coordination
  • Medulla oblongata - controls unconscious actions
• MRI scans


  Safely see activity in the brain
• Accommodation in the eye

  1. Ciliary muscles relax, suspensory ligaments tighten - lens becomes thin, light refracted less

  2. Ciliary muscles contract, suspensory ligaments slacken - lens becomes fatter, light refracted more
• Pupil


  Hole in the iris that can change size depending on light intensity
• Retina

  Contains rods and cones that respond to light
• Thermoregulation

  1. Brain senses blood temperature

  2. Sends nervous and hormonal signals to effectors

  3. Sweat glands cause evaporation to cool body

  4. Blood vessels dilate or constrict to increase/decrease heat loss
• Endocrine system


  System of glands that produce hormones that travel in the blood
• Pituitary gland


  Main or master gland that produces hormones in response to stimuli