cell organisation

• tissues are a group of similar cells that carry out a particular function
• an organ is a group of tissues that work together to carry out a function
• an organ system is a group of organs that work together to perform a function
• a catalyst is a substance that increases the speed of a reaction

  A) lock and key

  
• if an enzyme gets to hot, the shape of the active site will change (denature)
• if the pH is too low or high it interferes with the active sites shape
• amylase can be found in the salivary glands, pancreas and the small intestine

  
• lipase is found in the pancreas and small intestine

  A) lipids

  
• found in the stomach, pancreas and small intestine

  
• bile is produced in the liver, it neutralises the hydrochloric acid in the stomach, which helps the enzymes work better
• alveoli have large surface areas, thin walls and are surrounded by capillaries to help speed up the rate of diffusion
• trachea -- bronchi -- lungs -- bronchioles -- alveoli
• double circulatory system = left side, oxygenated blood, right side, deoxygenated blood
• oxygenated blood gets pumped to the muscles

  A) pathway of blood

  
• pacemaker cells provide small impulses that make the muscle cells that surround them contract
• strong, thick to carry blood at high pressure

  A) arteries

  
• also contains valves to ensure blood is flowing in the right direction, large lumen to help blood flow

  A) vein

  
• thin walls for diffusion, supplies food and oxygen, removes waste product, permeable walls

  
• red blood cells contain haemoglobin to bind with oxygen to release in cells, biconcave shape for a larger surface area
• white blood cells can change shape to engulf microorganisms, can produce antibodies and antitoxins
• platelets help blood clot and stop scabs from bleeding
• plasma carries everything like red and white blood cells, glucose, proteins, hormones, CO2 and more