Organisation

• Cells are the basic building blocks of all living organisms
• Tissue


  A group of cells with similar structure and function
• Organ


  A group of tissues performing specific functions
• Organ system


  A group of organs performing a specific function
• Organism


  A group of organ systems together
• Enzymes


  Protein molecules found in cells that speed up reactions in the body
• Enzymes


  • They can be reused as their shape remains unchanged
  • They depend on their shape to work
• Lock and key model

  Explains how enzymes work - the substrate (key) fits into the active site (lock) of the enzyme
• Metabolism


  Reactions that build up and break down molecules, controlled by enzymes
• Optimum temperature


  The temperature at which an enzyme works at its fastest rate
• Optimum pH


  The pH at which an enzyme works at its fastest rate
• Enzymes in the digestive system

  • Carbohydrase
  • Lipase
  • Amylase
  • Protease
• Carbohydrase


  Enzymes that break down carbohydrates into simple sugars
• Amylase


  A type of carbohydrase that breaks down starch
• Protease


  Enzymes that break down proteins into amino acids
• Lipase


  Enzymes that break down lipids (fats) into glycerol and fatty acids
• Bile


  Produced by the liver, helps digest lipids by emulsifying them
• Iodine test for starch

  Add iodine solution, if it turns blue-black then starch is present
• Biuret test for protein

  Add biuret solution, if it turns lilac then protein is present
• Lipid test


  Add ethanol, shake, then add water, if a cloudy white emulsion forms then lipids are present
• Benedict's test for sugars

  Add Benedict's reagent, heat in water bath, colour change to brick red indicates presence of sugars
• Aorta


  Major blood vessel carrying oxygenated blood from the heart to the body
• Vena cava


  Major blood vessel carrying deoxygenated blood from the body to the heart
• Pulmonary artery


  Carries deoxygenated blood from the heart to the lungs
• Pulmonary vein


  Carries oxygenated blood from the lungs back to the heart
• Valves in the heart


  Prevent the backflow of blood
• Double circulatory system


  Blood is pumped to the body by the left side of the heart and to the lungs by the right side
• Trachea


  The windpipe
• Bronchi


  The smaller tubes branching off from the trachea
• Alveoli


  The tiny air sacs in the lungs where gas exchange occurs
• Left atrium


  Part of the heart that receives oxygenated blood from the lungs
• Left ventricle


  Part of the heart that pumps oxygenated blood to the body
• Right atrium


  Part of the heart that receives deoxygenated blood from the body
• Right ventricle


  Part of the heart that pumps deoxygenated blood to the lungs
• Pacemaker


  Controls the resting heart rate by sending regular electrical impulses
• Arteries


  Have a narrow lumen, thick muscle and elastic tissue walls to withstand high blood pressure
• Capillaries


  Have very thin walls, only one cell thick, to allow for efficient diffusion
• Lumen


  The part inside where the blood is carried
• Arteries


  • Narrow lumen
  • Thick layer of muscle around the artery that can contract to pump blood
  • Thick elastic tissue layer that recoils and maintains pressure
• Capillaries


  The smallest blood vessels