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• Respiratory system


  • Provides the body with oxygen
  • Removes waste gases like carbon dioxide
• Carbon dioxide is a waste gas from the body and must be removed
• Breathing requires muscular action, which alters the shape and size of the thoracic cavity which contains the lungs
• Respiration


  Describes both the action of breathing in and out and the chemical process that takes place in the cells of the body to release energy
• Key terms


  • Lungs
  • Nose
  • Trachea
  • Bronchus
  • Bronchioles
  • Alveoli
• Diffusion


  1. Movement of particles from an area of high concentration to an area of lower concentration

  2. Gas diffuse in both directions between the alveoli and the blood capillaries

  3. Gaseous exchange is determined by the relative concentration of each gas
• Speed


  Measure of how quickly somebody or something travels the distance between 2 points
• Newton's first law of motion

  • A body will remain in a state of rest or uniform motion in a straight line unless it is acted on by an external force
• Newton's second law of motion

  • When a force acts on an object, it will accelerate in the direction of the force. The amount of acceleration is directly proportional to the force applied and inversely proportional to the mass of the object
• Newton's third law of motion

  • If an object A exerts a force on another object B, then object B exerts an equal and opposite force on object A
• Moment


  The turning effect of a force about a fixed point. Moments can be clockwise or anticlockwise. No turning effect is observed when moments are balanced. The point around which an object turns is called the pivot or fulcrum
• Couple


  Forces that are equal in size and opposite in direction that cause rotation
• The principle of moments states that when a system is in equilibrium, the anticlockwise moments are equal to the clockwise moments
• Center of gravity


  The point at which an object's weight is concentrated. If the center of gravity is above the base, the object will return to its original position when disturbed. If the center of gravity moves outside the base, the object will topple over
• Ecology


  The study of how organisms interact with each other and their environment
• Ecosystem


  A unit of the natural world
• Components of an ecosystem

  • Biotic (living things)
  • Abiotic (non-living features)
• Habitat


  The place where an organism lives
• Ecological niche


  The role that an organism has in a habitat
• Population


  The number of a species living in a habitat
• Community


  The collective term for all of the populations of organisms that live together in a habitat
• Types of equilibrium


  • Stable
  • Unstable
  • Neutral
• In stable equilibrium, the center of gravity is above the point of contact. In unstable equilibrium, the center of gravity is above the point of contact. In neutral equilibrium, the center of gravity is at the start of the journey
• Distance-time graph


  The gradient represents the speed
• When you breathe in, your lungs fill with oxygen
• In the lungs, oxygen passes into the blood and carbon dioxide passes out
• The body also loses excess oxygen when you breathe out
• Breathing rate


  The number of times a person breathes in and out each minute
• Parts of the respiratory system

  • Trachea
  • Left Lung
  • Bronchus
  • Diaphragm
• The site of aerobic respiration is the mitochondria, the "power house" of the cell
• Breathing rate


  How many times you breathe in and out each minute
• Substances harmful in cigarette smoke

  • Nicotine
  • Carbon monoxide
  • Tar
• Emphysema


  The air sacs in the lungs (alveoli) are damaged, causing larger air spaces instead of many small ones. This reduces oxygen supply to the body
• Bronchitis


  A condition where the airways in the lungs become inflamed, causing coughing and mucus production
• Lung cancer and cardiovascular diseases

  Caused by cigarette smoking
• As a person's age increases, their normal breathing rate decreases
• During strenuous exercise


  Rapid breathing cannot supply the body with enough oxygen. This causes a buildup of lactic acid, leading to a "stitch" after exercise. The body needs a recovery period to break down the lactic acid
• Chromatography


  A separation technique where a mixture is carried through a medium by a liquid or gas and separated into its components
• Decanting


  Used to separate a mixture of a liquid and an insoluble solid or two immiscible liquids with different densities
• Centrifugation


  Uses high speed rotation in a centrifuge to separate immiscible liquids or a sediment and a liquid. Applications include DNA preparation, separating blood serum and fats, and separating oils and waxes