Organisation

• what pumps deoxygenated blood?

  right ventricle
• what pumps oxygenated blood?

  left ventricle
• what is an enzyme?

  a protein that acts as a biological catalyst
• what do enzymes have?

  an active site with a complimentary shape that fits onto a substance in a reaction
• what happens to an enzyme if the temperature is too hot?

  bonds that hold it together will break

  active site will change shape

  enzyme will be denatured
• why do enzymes have an optimum pH

  if it’s too low or too high active site will change shape and the enzyme would denature
• what’s a digestive enzyme

  enzymes that convert food into small soluble molecules that can be absorbed into the bloodstream
• what does carbohydrase break down

  carbohydrates into simple sugars
• what is amylase

  a carbohydrase that breaks down starch into maltose
• what breaks down protein into amino acids

  protease
• what does lipase break down

  lipids into glycerol and fatty acids
• what does bile do

  neutralises stomach acid

  emulsifies fats
• where is bile produced, stored and released

  produced in liver

  stored in gall bladder

  released into small intestine
• what is biles role in digestion

  neutralises stomach acid as it’s alkaline and makes the conditions in small intestine alkaline rather then acidic, this allows enzymes to work better

  emulsifies fats into small droplets, this increases speed of digestion as it’s a bigger surface area for lipase to work on
• what is the difference between open and closed valves

  open- allow blood to flow back to heart

  closed- prevents blood flowing back to body
• how do you work out the rate of blood flow

  volume of blood /number of mins
• role of veins?

  carry lower pressure blood back to heart
• characteristics of veins

  large lumen for blood flow

  elastic fibres and smooth muscle

  valves the prevent back flow of blood
• role of capillaries

  carry blood close to every cell to exchange substances
• characteristics of capillaries

  really small lumen

  thin permeable walls
• role of arteries

  carry blood away from heart
• characteristics of arteries

  small lumen

  thick walls

  thick layers of muscle and elastic fibres for strength and to stretch
• role of red blood cells

  carry oxygen from lungs to cells
• characteristics of red blood cells

  biconcave disc shape

  red pigment haemoglobin

  no nucleus

  flexible