Topic 2 – Organisation

• Biological catalysts


  Speed up reactions, without being used up
• Lock and Key model

  • Enzyme is made of proteins
  • Active site (specific shape)
  • Fits complementary substrate
  • Enzyme-substrate complex
  • Products released
  • Enzyme unchanged
• Induced Fit


  • Active Site 100 % match
  • 1 enzyme = 1 type of substrate
  • Active site not 100% complementary
  • Changes shape after substrate binds
  • Tighter fit
  • 1 enzyme = many similar types of subs.
• Rate of reaction affected by

  • Temperature
  • PH
• Temperature


  • Low temp = Low K.E = few collisions
  • As temp increases: More K.E More Collisions
  • Until reaches optimum temp.
  • Beyond that, bonds break
  • Active site changes shape
  • Enzyme dentures
  • Substrate won't fit less collisions
• PH


  • At either extreme of PH: Bonds break
  • Active site changes shape
  • Enzyme denatures
  • Substrate won't fit less collisions
• Measuring Enzyme Activity Experiment

  1. Iodine solution: Bluey-black Brown

  2. Measure the time it takes for colour change

  3. Repeat experiment with different temperatures or pH

  4. Faster colour change = faster rate of reaction

  5. If rate slows down (enzyme has been denatured)
• Starch


  • Bluey- Black
  • Amylase
  • Brown
• FAIR TEST
• • Volume, Concentration of starch
  • Same amount of enzyme
  • Control temperature or pH (depending on which one you're not testing)
• Digestion


  Breakdown of larger molecules into smaller ones to aid absorption
• Mechanical


  Muscles and Teeth
• Large Molecules


  • Starch
  • Protein
  • Lipids
• Enzymes


  • Amylase
  • Protease
  • Lipase
• Small Molecules


  • Maltose
  • Amino Acids
  • Fatty Acid + Glycerol
• Organs and what happens

  • Mouth (Mechanical, Chemical)
  • Gullet (Connects mouth to stomach)
  • Stomach (HCL, Mechanical, Chemical)
  • Liver (Produces bile, Emulsifies fats, Neutralises HCL)
  • Gall Bladder (Stores bile)
  • Pancreas (Produces all 3 enzymes)
  • Small Intestine (Chemical, Food absorbed)
  • Large Intestine (Water absorbed)
  • Rectum (Stores faeces)
• Food tests are done to help identify what food is in the sample
• Food tests


  • Benedict's test (Reducing sugars)
  • Iodine (Starch)
  • Biuret (Proteins)
  • Sudan 3 (Lipids)
• Double circulatory system: Two joined circuits
• Double circulatory system


  1. Deoxygenated blood enters right atrium (Vena Cava)

  2. Blood is pumped to lungs from right ventricle (Pulmonary artery)

  3. At lungs, blood become oxygenated

  4. Oxygenated blood enters left atrium (Pulmonary vein)

  5. Blood is pumped to rest of the body from left ventricle (Aorta)
• Coronary arteries


  Give oxygenated blood to heart tissue for respiration
• Pacemaker


  • Releases electrical impulses that cause contraction of heart
  • If damaged, causes IRREGULAR heartbeat
  • The patient will need an ARTIFICIAL pacemaker – be careful of MRI or magnets
• Blood vessels


  • Artery (Takes blood OUT of heart, Thick muscle layer, Small lumen, Higher Pressure, No valves)
  • Capillary (One cell thick, Exchange between blood and respiring cells)
  • Vein (Takes blood IN to heart, Thin muscle layer, Large Pressure, Low Pressure, Has Valves)
• Calculate rate of breaths per minute

  Number of Breaths / Time (minutes)
• Calculate rate of blood flow

  Volume (mL) / Time (minutes)
• Coronary arteries supply O2 to heart cells

  • Fatty deposits build up in coronary arteries
  • Lumen becomes narrow
  • Less blood flows to heart cells = less O2
  • Heart attack!
• STENTS


  Springs placed inside arteries, keep them open, more blood flows to heart cells
• STATINS


  Medicines that lower the amount of "bad" cholesterol "LDL" (fat) in the blood, so less fatty deposits can form
• Pros and Cons of Statins

  • Pros: Reduce risk of strokes, heart attack and CHD, Increase HDL (good cholesterol)
  • Cons: Negative side effects (muscle weakness), Lifelong drug (take daily), Takes time for effect
• Artificial Hearts


  Temporary used to pump blood until a donor heart is found
• Pros and Cons of Artificial Hearts

  • Pros: Keeps person until donor is found, No organ rejection (no antigen)
  • Cons: Surgery – bleeding/infection, Electric motor can wear out, Might need drugs to thin blood (to prevent strokes/blood clots)
• Heart Valves


  • Keep blood flowing in one direction
  • Can get damaged become leaky/stiff
• Artificial blood


  Help keep person alive in emergency (huge blood loss)
• Blood Components


  • Red Blood Cells (Carries O2, Haemoglobin, Biconcave = ^SA, No Nucleus)
  • White Blood Cells (Fight infection, Phagocytosis, Make Antibodies, Make Antitoxins)
  • Platelets (Not cells, Help seal wounds, Clump together, Blood clot)
  • Plasma (Liquid in the blood, Contains: Nutrients/Waste/Hormones/Cells)
• Plant Cell Organisation


  • Waxy Cuticle (Prevents water loss)
  • Epidermal (top) (Cover the top, Transparent – allows light through)
  • Palisade layer (Palisade cells - photosynthesis)
  • Spongy Mesophyll layer (Air spaces – gas exchange)
  • Vascular bundle (Xylem and phloem - Delivers nutrients (roots leaf))
  • Epidermal (bottom) (Contains guard cells Stomata)
• Stomata


  • Holes underside of leaf
  • Sensitive to LIGHT (open in light)
• Palisade cells


  • Lots of chloroplast (more photosynthesis)
  • Tall (large SA – more CO2 absorbing)
  • Thin (fit many together)
  • Found near top of leaf (lighter)
• Xylem


  Dead cells joined end-end, Hollow, Lignin (strength)
• Phloem


  Living cells, Platelets with pores, H2O + Minerals (up), Sugars (up and down)
• Transpiration


  1. Water evaporates and diffuses out of leaf through stomata

  2. Shortage of water in the leaf

  3. Water drawn up the Xylem vessel

  4. Water drawn up from the soil into roots

  5. Continuous stream of water from leaf to roots