organisation

• what is a tissue

  A group of cells with similar structure and function
• what is a organ

  A group of specific tissues working together for a specific function
• what is an organ system

  Organs that work together to form organisms
• what are the food groups

  • Lipids
  • carbohydrates
  • proteins
• what is digestion

  large food particles are broken down into smaller molecules by enyme
• what are the 6 stages of digestion

  1. mouth
  2. oesophagus
  3. stomach
  4. small intestines
  5. large intestines
  6. faeces
• what do the enzymes in the mouth do

  break down starch into smaller sugar molecules
• explain how the stomach works

  • it contains hydrochloric acid which helps enzymes to digest proteins
  • the stomach muscles contract resulting in a churning motion which turns food down into liquid so it has a larger surface area for enzymes to digest
• explain how the small intestine works

  • enzymes released by pancreas and liver to aid digestion
  • intestine walls release another enzyme to further digest proteins and lipids
  • small food molecules are absorbed into blood stream via active transport and diffusions
• why does the pancreas release and enzyme

  • to continue the digestion of starch and proteins and also start the digestion of lipids
• why does the liver produce bile

  • speed up lipid digestion and to neutralise stomach acids
• what does the large intestine do

  • absorbs water into blood stream
• what is the waste product of digestion used for

  • used by the body to produce new carbohydrates, lipids and proteins
  • repiration and glucose
• what is enzyme

  biological catalysis

  large protein molecules that have an active site where substrate attaches
• what is the lock and key theory

  • enzymes have an active site that is unique to a certain kind of substrate
• what are proteins

  • long chains amino acid
  • broken down by protease
• what is starch

  • a type of carbohydrates
  • broken down by amylase
• what is lipids

  • produces three fatty amino acids attached to one glycerol
  • digested by lipase
• where is amylase found

  Found in saliva and pancreatic fluid
• where is protease found

  Found in the stomach, pancreas and small intestine
• where is lipase produced

  Found in pancreatic fluid and small intestine
• what is bile

  • not an enzyme
  • made in the liver stored in gall bladder
  • speeds up digestion of lipids
  • turns large lipid molecules into smaller ones
  • emulsifies lipids and increases surface area and reaction time
  • alkali and neutralises stomach acids
• what is meant when a enzyme becomes denatured

  the active site becomes damaged due to the shaking so substrate can no longer fit
• what test do we do for the Prescence of starch

  • iodine
  • goes from browny-orange to black or blue black
• what test do we do for reducing sugars

  • benedict's solution
  • from blue to green, yellow and brick red
• what do we use to test for proteins

  • biuret
  • from blue to purple
• what test do we use for lipids

  • sudan III
  • A layer of red fat forms on top
• how many chambers does the heart have?

  4
• what are the two chambers called

  • Atrium
  • Ventrical
• what blood vessels enter and exit the heart with deoxygenated blood?

  • vena cava
  • pulmonary artery
• what blood vessels transport oxygenated blood to the heart from lungs?

  • Pulmonary vein
  • aorta
• What do the valves in the heart do?

  Prevent the back flow of blood
• why is the left side of the heart muscle thicker than the rest?

  It has to pump blood around the body so it requires more energy
• Humans have a double circulator system
• where are the pacemaker cells found?


  In the right atrium
• what is an artificial pacemaker


  An electrical device that send electric impulses to damaged pacemaker cells to make the heart contract
• What are the features of arteries

  • small lumen
  • elastic fibres in the muscular walls
  • withstands high blood pressures
• what are the features of capillaries

  • one cell thick wall to allow shorter distance for diffusion
• what are the features of veins?

  • large lumen
  • low blood pressure
  • valves to prevent backflow
• what are the parts of blood plasma

  • RBC
  • WBC
  • Platelets