B2 ORGANISATION AND HEALTH

• Cells


  Make up all living things
• Tissue


  A group of specialised cells with a similar structure and function, can be made of more than one type of cell
• Tissue examples


  • Muscular tissue
  • Epithelial tissue
• Organs


  Formed from a number of different tissues, working together to produce a specific function
• Organ example


  • Stomach
• Organ systems


  Organs organised to work together to perform a certain function
• Organ system example


  • Digestive system
• Organs in the digestive system

  • Glands (salivary glands, pancreas)
  • Stomach
  • Small intestine
  • Liver
  • Gall bladder
  • Large intestine
  • Rectum
  • Anus
• Enzymes


  Biological catalysts that increase the rate of reaction without being used up
• Enzymes


  • They can both break up large molecules and join small ones
  • They are protein molecules and the shape of the enzyme is vital to its function
  • Each enzyme has its own uniquely shaped active site where the substrate binds
• Lock and Key Hypothesis

  1. Substrate shape is complementary to active site shape, forming enzyme-substrate complex

  2. Reaction takes place and products are released
• Optimum pH


  The pH at which an enzyme works best, usually around 7 but some have a low optimum pH
• Optimum temperature


  The temperature range around 37 degrees Celsius at which an enzyme works best
• Temperature increases


  Rate of reaction increases up to optimum, then rapidly decreases
• Denaturation


  When the bonds in the enzyme structure break, changing the shape of the active site so the substrate can no longer fit
• Types of enzymes


  • Carbohydrases
  • Proteases
  • Lipases
• Carbohydrase example


  • Amylase
• Protease example


  • Pepsin
• Tests for biological molecules

  • Benedict's test for sugars
  • Iodine test for starch
  • Biuret test for protein
  • Emulsion test for lipids
  • Sudan III test for lipids
• Bile


  Produced in the liver, stored in the gallbladder, released into the small intestine. Alkaline to neutralise stomach acid, emulsifies fats.
• Investigating effect of pH on enzyme activity

  1. Use iodine to detect presence of starch

  2. Warm amylase, starch and buffer solution

  3. Take samples at intervals and test with iodine

  4. Time until starch is completely broken down

  5. Calculate rate using 1000/time
• Rate of enzymatic reactions


  Calculated as change/time
• Heart


  An organ in the circulatory system that pumps blood around the body
• Circulatory system


  Carries oxygen and nutrients to every cell and removes waste products
• Double circulatory system


  Deoxygenated blood flows to the right atrium, right ventricle, lungs, then oxygenated blood flows to the left atrium, left ventricle, body
• Heart structure


  • Muscular walls
  • Thicker left ventricle wall
  • 4 chambers
  • Valves
  • Coronary arteries
• Heartbeat process


  Blood flows into atria, atria contract to force blood into ventricles, ventricles contract to pump blood out
• Pacemaker


  Group of cells in the right atrium that provide electrical stimulation to control the natural resting heart rate
• Artificial pacemaker


  Electrical device that produces a signal to make the heart beat at a normal speed
• Blood vessels


  • Arteries - carry blood away from heart, have muscle and elastic fibres
  • Veins - carry blood towards heart, have wide lumen and valves
  • Capillaries - allow close contact between blood and cells, have thin permeable walls
• Lungs


  Found in the thorax, supply oxygen to blood and remove carbon dioxide
• Components of the gas exchange system

  • Trachea
  • Intercostal muscles
  • Bronchi
  • Bronchioles
  • Alveoli
  • Diaphragm
• Ventilation


  Ribcage and diaphragm move to increase chest volume, decreasing pressure and drawing in air
• Gas exchange


  Oxygen diffuses from alveoli into blood, carbon dioxide diffuses from blood into alveoli
• Alveoli adaptations


  • Large surface area
  • Good blood supply
  • Thin walls
• Blood


  Made up of plasma, red blood cells, white blood cells and platelets
• Components of blood


  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
• Red blood cells


  • Biconcave disc shape
  • No nucleus
  • Contain haemoglobin
• White blood cells


  Part of the immune system, defend against pathogens
• Types of white blood cells

  • Those that produce antibodies
  • Those that engulf and digest pathogens
  • Those that coordinate the immune response