November

• Why do people with CF have breathing difficulties?

  The mucus blocks the airways so air flow to lungs is reduced
• Why do people with CF have problems absorbing nutrients?

  Mucus prevents pancreatic enzymes from entering the small intestine, so large food molecules are not broken down and cannot be absorbed
• How do goblet cells release mucus by exocytosis?

  The mucus is contained in membrane-bound vesicles inside the cell these vesicles fuse with the cell membrane releasing the mucus.
• How does osmosis occur in the cells lining the bronchi?

  • The partially permeable membrane allows water molecules to pass while blocking solutes.
  • Water moves through aquaporins, following its concentration gradient.
• Why was maltose detected earlier in tube A than in tube B?

  • Tube A had a larger surface-area-to-volume ratio, enhancing diffusion.
  • A shorter diffusion pathway in tube A allowed faster maltose movement
• Why are stents used to treat atherosclerosis?

  • Stents widen narrowed coronary arteries, restoring blood flow.
  • They reduce the risk of heart attacks by improving oxygen delivery to the heart.
• How the formation of a blood clot in the coronary artery could cause the death of the patient?


  Blocks the coronary artery so the heart muscles doesn't get oxygen causing a heart attack
• What enzymes are active in blood clotting?

  Thrombin and thromboplastin are active enzymes.
• Which clotting factor is soluble in blood plasma?

  Fibrinogen is soluble in plasma.
• What drugs are used to prevent stent thrombosis?

  Anticoagulants or antiplatelet drugs, such as aspirin.
• Which sugars in nectar contain glycosidic bonds?

  Sucrose contains glycosidic bonds.
• Why is the butterfly’s circulation different from mammals?

  Insects are small the cells will not be far from the sinuses so diffusion can supply oxygen and nutrients from the blood and they have an open circulation system.
• What evidence does an electron micrograph provide for membrane structure?

  • The observed membrane thickness matches the phospholipid bilayer, composed of phosphate heads and fatty acid tails.
• Why is cholesterol positioned within the membrane?

  Cholesterol and fatty acid tails is a non-polar molecule. Cholesterol will be located within the fatty acid tails of the membrane. OH group will be located near the phosphate heads
• Describe the dipolar nature of water

  The partially positive charge on the hydrogen and partially negative charge on oxygen
• Explain the permeability of the cell membranes to each chemical

  Water is small enough to move by osmosis between the phospholipids,

  Steroids are non-polar so can diffuse through the membrane.

  glucose is polar so passes through protein channels,

  ions are polar so pass through protein channels.
• Describe the shape and position of this line

  The graph will be the same shape because the left and right-hand sides beat simultaneously, but peaks will be lower because pressure in right hand side is lower as blood only pumped to lungs
• Benefits of plant statins

  Lower blood cholesterol so reduce risk of CVD
• Why there was an increase in the percentage of patients taking statins over the 3 years of the study

  Statins seen as more effective, and may be prescribed more frequently
• Compare the change in the use of platelet inhibitory drug

  Use of both increased over 3 years, greater increase in the use of antihypertensive than in platelets inhibitory drugs, the use of of platelets inhibitory drugs is always greater that antihypertensive