Topic 2: Organisation

• What is the food test for starch?

  iodine solution

  if negative for starch then colour remains orange / brown

  If positive for starch then colour goes from orange to blue / black
• What is the food test for proteins ?

  Biuret regent

  if negative colour is blue

  if posative colour is pink/ purple
• What is the food test for lipids?

  Ethanol

  if negative becomes colourless

  if positive becomes cloudy emulsion
• what is the food test for reducing sugars?

  Benedict solution

  if negative becomes blue

  if positive becomes green if there's a little bit of glucose and orange if lots of glucose is found
• what is osmosis?

  diffusion of water from a dilute to a concentrated solution through a partially permeable membrane
• what is active transport?

  moving substances from a more dilute to a concentrated solution through a concentration gradient which requires energy from respiration
• what two enzymes are made in the pancreas?

  protease and carbohydrase
• what other subtances are transported in the blood plasma?

  hormones

  carbon dioxide

  water

  amino acids

  minerals
• what blood vessels carry deoxygenated blood ?

  Pulmonary artery

  vena cava
• what blood vessel carries blood to the right atrium?

  veins
• what condition can be treated with an artificial pace maker?

  Arrhythmia
• why does the mass of the eggs increase?

  water moves into the egg by osmosis from a high to a low concentration through a partially permeable membrane
• how can a student change the experiment to calculate the concentration of the solution in the egg?

  use 5 different concentrations of sugar solution in the beaker, then using a graph plot the percentage change and then determine the concentration of the point where the line crosses the zero percentage change
• A scientist investigated the effect of bile on the breakdown of fat in a sample of milk.

  Explain why the indicator in both tubes became colourless?

  lipase will break down fat into fatty acids making glycerol. the fatty acids lower the PH and then when the PH gets below 10 it becomes colourless
• bile emulsifies fats creating a larger surface area for lipase to work on and break down fats more quickly
• what theory is shown here?

  lock and key

  A) enzyme

  B) active site

  C) substrate

  
• Amylase is an enzyme which breaks down starch
• Lipase is an enzyme that breaks down lipids into fatty acids and glycerol
• protease is an enzyme that breaks down amino acids into protein
• Digestive enzymes convert food into small soluble molecules that can be absorbed into the bloodstream
• Bile is made in the liver and stored in the gall bladder
• The right ventricle pumps blood to the lungs where gas exchange takes place
• The left ventricle pumps blood around the rest of the body
• The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker
• Artificial pacemakers are electrical devices used to correct irregularities in the heart rate
• what blood vessel is this?

  artery

  
• what blood vessel is this?

  vein

  
• structure of arteries?

  Always carry oxygenated blood away from the heart

  have thick muscular walls to pump blood under high pressure

  have narrow lumen
• structure of veins?

  carry deoxygenated blood to the heart except from pulmonary vein

  have thin walls

  wide lumen
• In coronary heart disease layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
• treatment for CHD?

  stents - keep the coronary arteries open

  statins - pills which reduce blood cholesterol levels which slows down the rate of fatty material deposit
• Faulty heart valves can be replaced using biological or mechanical valves
• risk factors for diseases?

  • persons lifestyle
  • diet - diabetes
  • lack of exercise
  • smoking / alcohol
  • enviroment
• what causes cancer?

  changes in cells that lead to uncontrolled growth and division
• Benign tumours are growths of abnormal cells which are contained in one area, usually within a membrane. They do not invade other parts of the body
• Malignant tumour cells are cancers. They invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours.
• Meristems are found at the tips of roots and shoots. Here, unspecialised stem cells undergo a type of cell division called 
• how are plant leaves adapted for photosynthesis?

  Thin and flat shape, large surface area, chlorophyll pigments, and stomata for gas exchange.
• The palisade mesophyll layer of the leaf is adapted to absorb light efficiently.
• what are the cells in the palisade mesophyll layer packed with?

  • are packed with many chloroplasts
  • are column-shaped and arranged closely together
  • towards the upper surface of the leaf