TOPIC 2 ORGANISATION

• what are cells


  Cells are the basic units of structure and function in living things
• what are tissues


  a group of specilised cells that carry out one function
• what is an organ


  a group of tissue that carry out a joint function
• what is an organ system


  A group of organs working together to perform a particular function
• salivary glands


  amalyse enyzme in the saliva
• whats the gullet


  oesophagus
• whats the livers function

  produces bile
• what does bile do

  Neutralises stomach acid and emulsifies fats
• whats the function of the stomach

  has hydrochloric acid

  kills bacteria

  gives right ph for protease enzyme

  produces pepsin
• what does the gall bladder do

  It stores bile before it's released into the small intestine
• pancrease


  has protease, amylase and lipase
• large intestine


  absorbs excess water
• small intestine


  produces protease amylase and lipase

  where the digested food is absorbed out of the digestive food is absorbed
• what doe
• define a catalyst


  substance that speeds up the rate of a chemical reaction
• what are enzymes


  biological catalysts
• what are enzymes made from

  proteins chains of amino acids
• what does lipase do


  It breaks down fats into fatty acids and glycerol
• where can lipase be found

  Pancreas and small intestine
• what does protease do

  breaks down proteins into amino acids
• where is protease found

  Stomach, pancreas, small intestine
• what does amylase (cabrohydrase) do

  breaks down startch into sugars
• what does bile do

  Bile is made in the liver and stored in the gall bladder. It is alkaline to neutralise hydrochloric acid from the stomach. It also emulsifies fat to form small droplets which increases the surface area. The alkaline conditions and large surface area increase the rate of fat breakdown by lipase.
• why is bile alkaline


  To neutralise hydrochloric acid from the stomach
• test for starch


  Iodine solution

  -Posotive:Blue black

  -Negative:Orange yellow
• test for protein


  Buriet solution

  -Positive:Purple

  -Negative:No change
• test for sugar


  Benedict's solution

  turns brick red
• test for lipids


  emulsion test, sudan III

  if lipids are present shake and white cloudy emulsion forms
• explain the lock and key theory

  hthe lock is the enzyme and the key is the substrate. Only the correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).
• how does temperature affect an enzyme

  1. At low temperatures there is less kinetic energy so less collisions between enzyme and substrate, leading to a low rate of reaction. 2. At the optimum (best) temperature there is more kinetic energy so more collisions between enzyme and substrate leading to a high rate of reaction. 3. Above the optimum temperature the bond that hold the enzyme together break and the 3D shape is lost. The active site is no longer the same shape so the rate of reaction is lowers.
• how does ph affect an enzyme

  Every enzyme has an optimum pH, where it is most active, and if the pH drops too low or rises too high, the enzyme may denature
• where is amylase found


  Salivary glands, pancreas, small intestine
• What's a double circulatory system?

  Blood passes through the heart twice for each complete circuit of the body
• Explain the double circulatory system

  deoxygenated blood flows into the right atrium then into the right ventricle to the lungs and take in oxygen

  
  

  oxygenated blood flows into the left atrium then into the left ventricle which pumps oxygenated blood around the body
• what are the valves


  keep blood from flowing backwards
• what happens if blood flows backwards

  The shape of the valves means that when the pressure is greater on concave side rather then convex the valves stay shut.

  Strong pillar muscles contract causing tendons to keep the valve shut.
• what are the 4 chambers

  right atrium, right ventricle, left atrium, left ventricle
• what do the 4 chambers do

  seperate oxygenated blood from deoxygenated blood
• What is the pathway for deoxygenated blood into the heart?

  Vena cava
• What is the pathway for oxygenated blood into the heart?

  Pulmonary vein