Organisation

• Tissue


  A group of cells with a similar structure and function
• Organ


  A combination of tissues carrying out a specific function
• Cell


  The basic building blocks of all living things
• Organ system


  Organs working together to form whole living organisms
• Cells are the basic building blocks of all living things
• A group of cells with a similar structure and function is called a tissue
• An organ is a combination of tissues carrying out a specific function
• Organs work together within an organ system
• Organ systems work together to form whole living organisms
• Iodine


  Used to test for the presence of starch
• Positive result for starch test

  Colour changes to blue-black
• Independent variable


  pH of the buffer solution
• Dependent variable


  Time taken for the reaction to complete (how long it takes for all the starch to be digested by the amylase)
• Effect of pH on the Rate of Reaction of Amylase (Required Practical)

  1. Use the marker pen to label a test tube with the first value of pH buffer solution (pH 4) and stand it in the test tube rack

  2. Into each well of the spotting tiles, place a drop of iodine

  3. Using a measuring cylinder, measure 2cm of amylase and pour into the test tube

  4. Using a syringe, measure 1cm' of the buffer solution and pour into the test tube

  5. Leave this to stand for five minutes and then use the thermometer to measure the temperature. Make a note of the temperature

  6. Add 2cm' of starch solution into the test tube, using a different measuring cylinder to measure, and begin a timer (leave the timer to run continuously)

  7. After 10 seconds, use a pipette to extract some of the amylase/starch solution and place one drop into the first well of the spotting tile. Squirt the remaining solution back into the test tube

  8. Continue to place one drop into the next well of the spotting tile, every 10 seconds, until the iodine remains orange

  9. Record the time taken for the starch to be completely digested by the amylase by counting the wells that were tested positive for starch (indicated by the blue/black colour change of the iodine). Fach well represents 10 seconds of time

  10. 10. Repeat steps 1 to 8 for pH values 7 and 10
• Benedict's reagent


  Used to test for the presence of sugar
• Positive result for sugar test

  Solution changes from blue-green to yellow-red when heated
• Biuret test


  Used to test for the presence of protein
• Positive result for protein test

  Solution changes from blue to pink-purple
• Sudan III


  Used to test for the presence of lipids
• Positive result for lipid test


  Lipids separate and the top layer turns bright red
• Digestive system


  Breaks down large molecules into smaller, soluble molecules which are then absorbed into the bloodstream
• Parts of the digestive system

  • Mouth
  • Tongue
  • Oesophagus
  • Stomach
  • Liver
  • Gall bladder
  • Pancreas
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
• Enzyme


  A biological catalyst that speeds up chemical reactions without being changed or used up
• Enzymes


  • They lower the activation energy required for the reaction to occur
  • They are made up of chains of amino acids folded into a globular shape
  • They have an active site which the substrate (reactants) fits into
  • They are very specific and will only catalyse one specific reaction
  • They work optimally at specific conditions of pH and temperature, and will denature in extremes
• Enzymes and their reactions

  • Amylase - breaks down starch into sugars
  • Protease - breaks down proteins into amino acids
  • Lipase - breaks down lipids into glycerol and fatty acids
• The products of digestion are used to build new carbohydrates and proteins, and some of the glucose is used for respiration
• Bile is produced in the liver and stored in the gall bladder. It is an alkaline substance which neutralises the hydrochloric acid in the stomach and emulsifies fats
• Artery


  Blood vessel that carries oxygenated blood away from the heart
• Vein


  Blood vessel that carries deoxygenated blood towards the heart
• Capillary


  Narrow blood vessel that forms networks to closely supply cells and organs between the veins and arteries
• Differences between arteries and veins

  • Arteries have thicker, more muscular walls
  • Arteries carry blood at a higher pressure
  • Veins have wider lumens and contain valves to prevent backflow
  • Veins carry blood at a lower pressure
• Pulmonary circulation


  Circulation that serves the lungs and brings deoxygenated blood to exchange waste carbon dioxide for oxygen
• Systemic circulation


  Circulation that serves the rest of the body and transports oxygen, nutrients, and waste
• Sino-atrial node (SAN)


  Located in the right atrium and stimulates the atria to contract
• Atrio-ventricular node (AVN)


  Located between the ventricles and stimulates them to contract
• Artificial pacemakers can be surgically implanted into a person if their heart nodes are not functioning correctly
• Alcohol and drugs


  Can affect heart rate and blood pressure
• Coronary heart disease is a condition resulting from blockages in the coronary arteries, which supply blood to the heart itself
• Coronary heart disease is a major cause of many deaths in the UK and around the world
• Lifestyle factors that increase the risk of coronary heart disease

  • Diet high in saturated fat
  • Smoking
  • Stress