organisation (2)

• tissue

  a group of similar cells working together
• organs

  a group of similar tissues that work together
• organ system

  a group of similar organs working together
• parts of the digestive system

  salivary glands , stomach , small intestine , liver , pancreas , gall bladder , large intestine , rectum , anus
• function of the glands (salivary glands and pancreas)

  produce digestive juices containing enzymes which break down food
• function of the stomach

  produce hydrochloric acid to kill bacteria and to provide the optimum ph for the protease enzyme to work
• function of the small intestine

  where soluble molecules are absorbed into the blood
• function of the liver

  produce bile
• function of the gall bladder

  stores bile to help digest lipids
• function of large intestine

  absorb water from undigested food to produce faeces
• function of the rectum and anus

  pass out undigested food that has been produced into faeces
• enzymes

  biological catalysts
• lock and key hypothesis

  the shape of the substrate is complementary to the shape of the active site, so when they bond it forms an enzyme-substrate complex, once bound, the reaction takes place and the products are released from the surface of the enzymes
• optimum temperature for an enzyme

  37 degrees
• optimum ph for enzymes

  7
• how temperature effects enzymes

  rate of reaction increases as the temperature increases up to the optimum but anything above this will lead to a rapid decrease and eventually the reaction will stop due to the enzyme denaturing and the active site changing shape
• how ph effects enzymes

  if its too high or low the amino acids that make up the protein will be affected and the shape of the active site so the substrate can no longer fit in (enzyme is denatured)
• function of carbohydrases

  convert carbohydrates into simple sugars
• function of proteases

  convert proteins into amino acids
• function of lipases

  convert lipids into fatty acids and glycerol
• test for sugars

  Benedict's
• positive result of sugar - benedicts

  brick red
• test for starch

  iodine
• positive result for starch - iodine

  blue-black
• test for protein

  biuret
• positive result for protein - biuret

  purple
• test for lipids

  ethanol / emulsifcation
• positive result for lipids - ethanol

  cloudy
• where's bile produced

  liver
• where's bile stored

  gallbladder
• function of bile

  alkaline to neutralise hydrochloric acid from the stomach , breaks down large molecules of fat into smaller ones ( by emulsifying them )
• what organ system is the heart in

  circulatory system
• heart blood pumping in a double circulatory system

  1 in the right atrium (deoxygenated blood) then into the right ventricle which pumps it into the lungs. 2 into the left atrium (oxygenated blood) then int the left ventricle which pumps oxygenated blood around the body
• structure of the heart

  muscular walls to provide a strong heartbeat, 4 chambers to separate the oxygenated blood from deoxygenated blood, valves to make sure blood does not flow backwards, coronary arteries to provide its own oxygenated blood supply
• process of blood flowing through the heart

  blood flows into the right atrium through the vena cava, and the left atrium through the pulmonary vein, the atria contract causing blood into the ventricles, the ventricles contract and the blood is pushed in the right ventricle into the pulmonary artery to be taken to the lungs. blood in the left ventricle is pushed into the aorta to be taken around the body.
• what is the natural resting heart rate controlled by

  a group of cells in the right atrium that act as a pacemaker
• three types of blood vessels

  arteries , veins , capillaries
• function of arteries

  carry blood away from the heart
• structure of the arteries

  layers of muscle in the walls to make them strong, elastic fibres to help them stretch and withstand the high pressure
• function of the veins

  carry blood in to the heart