Biology paper 2 aqa combined

• Alveoli— The lungs part of the breathing system which takes air in and out of the body oxygen diffuses from air to blood and carbon dioxide diffuses from blood to air the lungs are adapted for efficient gas exchange
• Change in heart rate

  • heart rate increases
  • can be measured by taking your pulse at the wrist
  • measured in beats per minute
• When you exercise your stroke volume increases

  • heart muscle pumps more strongly so deoxygenated blood passes back into the heart which stretches the walls of the ventricles causing them to become thicker
• ecosystems and abiotic factors

  • organism —a single living individual
  • population—all organisms of the same species in an area
  • Community— all the population in area
  • ecosystem all living organisms and not living components in an area
• factors affecting distribution

  • living factors
  • prey
  • Predator
  • competitor
  • nonliving factors
  • light
  • average temperature or rainfall
  • pollution
• Translocation

  • Radioactive carbon atoms will be detected in the phloem explain why
  • common dioxide will be used in photosynthesis to make glucose some of the glucose will be converted to sucrose which is transported around the plant in the phloem
• blood vessels

  • veins
  • have a large space for blood to flow easily back to the heart
  • thicker wall than artery
  • valves to stop blood flowing backwards so that it is returned to the heart
  • arteries
  • has a space where blood flows and thick wall of muscle and elastic fibres
• aerobic respiration


  requires oxygen

  releases a lot of energy

  glucose broken down completely

  occurs mostly in mitochondria
• Anaerobic respiration

  does not require oxygen

  releases much less energy

  glucose only partly broken down to lactic acid

  does not occur in mitochondria
• Blood plasma

  liquid part of blood

  • carries blood cells that contains many dissolved substances example carbon dioxide and glucose
• White blood cells

  larger than red blood cells and have a nucleus

  A part of the immune system which attacks pathogens in the body
• platelets

  fragments of larger cells

  have no nucleus and causes blood to clot when a blood vessel is damaged
• explain how distillation can be used to produce potable water in a village that is close to the sea

  • salty water is heated until the water evaporates forming steam
  • steam is condensed in another container to give pure water
  • Salt and other impurities are left behind in the salty water
• Insulin


  Regulates blood sugar levels
• Adrenaline

  
  
• Thyroxine


  Regulates metabolism
• Oestrogen


  Regulates female reproductive system
• Testosterone


  Regulates male reproductive system
• Growth Hormone


  Regulates growth and development
• light intensity core practical

  • place 20 algae balls and the same volume of indicator solution in each bottle and replace screw tops
  • check colour against colour chart and record the starting pH
  • If using a hot lamp please the water tank between the lamp and bottles
  • leave bottles equal distance from the lamp
  • you will then discover in your conclusion that the closer the bottles are to the lamp the quicker the algae balls will grow and be further away the bottle is away from the lamp the more time it takes to photosynthesise
• Aerobic respiration— Chemical reaction that takes place mostly inside mitochondria in the cell

  • Glucose add oxygen gives Corbin Carbon dioxide add water
  • in animals: It is used
  • for metabolic processes to build larger molecules from smaller ones
  • in plants and animals it is used
  • to build molecules from smaller ones
• Parasitism and mutualism 


  parasite flea