Organisation

• what is an enzyme?

  • a biological catalyst
• what is the effect of pH on the enzymes?

  • the optimum pH for enzymes is 7
  • if the pH is too high or too low the bonds that hold amino acid chain together to make protei will be destroyed
  • changing the shape of the active site
  • substrate cannot fit into it reducing the rate of reactivity
• how does temperature effect enzymes?

  • enzymes work fastest at optimum temperatures
  • too high the bonds will break and the enzyme will distort and lose its shape
  • decreasing the rate of activity
  • eventually it denatures
• Why do you label a test tube with the pH to be tested?

  To identify the pH condition of the experiment
• What is the purpose of starting the stopwatch when mixing starch solution?

  To measure the time taken for digestion
• What indicates that starch has been digested in the experiment?

  When iodine solution remains orange-brown
• What does it mean if the iodine solution turns blue-black?

  Starch is present in the mixture
• What should be done after every 10 seconds during the experiment?

  Place a drop of the mixture on iodine
• What is the significance of repeating the experiment at different pH values?

  To determine optimal pH for enzyme activity
• Buffer

  • a solution that resists changes in ph
• independent variable

  • the PH buffer
• dependant variable

  • time taken for the dissolving starch
• control

  • the temperature of the water bath
• describe the digestion of starch in the human body?

  • starch digestion begins in the mouth due to saliva which contains the enzyme amylase
  • amylase breaks down starch into maltose
  • the pancreas also produces amylase which is released in the small intestine
  • this further digests into starch
• describe the enzyme practical up to step 4 :

  1. use a syringe and place 2cm3 of amylase solution into a test tube
  2. another syringe, add 1cm3 of PH buffers to the test tube
  3. place the test tube in a water bath of 30c for 5 mins
  4. while you wait get a spotting tile and add one drop of iodine solution to each spot
• describe the enzyme practical from starting with step 5:

  5.after 5 mins, use another syringe to add 2cm3 of starch to the solution and start a stopwatch, mix for 10 seconds

  6. take a drop of the solution and add to each spot on the tile every 10 seconds

  7. repeat step 6 until the iodine remains orange

  8. record the time it takes for it to digest starch

  9. repeat with different PH buffer
• carbohydrases breaks dow carbohydrates to

  simple sugars
• proteases break down protein into

  amino acids
• lipases break down lipids into

  • glycerol
  • fatty acids
• how is blood transported in the heart?

  • deoxygenated blood- VCRAV
  • pulmonary artery - pulmonary vein
  • LAVA
• why does the left side of the heart have thicker walls?

  • due to the higher pressure having to pump blood to the body
• AA

  • the Artery carries blood Away from the heart
  • has thick walls and thin lumen to withstand high pressure
• Capillary

  • one cell thick walls
  • to allow fast diffusion between blood and cells
• VB

  • the Vein carries blood Back to the heart
  • thin walls and a wide lumen to prevent backflow
• explain the lock and key theory?

  • the substrate binds to the active site
  • the shape of the active site and substrate are complementary to eachother
  • a chemical reaction occurs to produce smaller molecules
• explain how a stent works as treatment for a person with a blockage in a coronary artery

  • it widens the artery so more blood can flow through