B3 | Mindmap

Exchange of materials
1. Osmosis
  1. Diffusion of water down a concentration through a semi-permeable membrane
  2. Causes net water movement into and out of cells
2. Active transport
  1. Against concentration gradient
  2. Uses energy from respiration
  3. Cells absorb ions, sugar and salt this way
3. Sports drinks
  1. Contains sugars and ions
  2. Reseach shows that water is as effecive for normal amounts of exercise
  3. Replaces sugars, ions and water lost in exercise and through sweating
4. Lungs
  1. Large surface area, thin walls and steep concentratn gradients all help with the diffusion of oxygen.
  2. Alveoli increase the surface area so that there is more space for diffusion to happen across
  3. Adapted to make gaseous exchange as efficient as possible
  4. The intercostal muscles move the ribcage up and out and your diaphragm moves down making your thorax bigger, this makes your lungs expand
5. Breathing aids
  1. There are negative pressure breathing aids such as the iron lung and positive pressure breathing aids which force air into your body
  2. All breathing aid have advantages and disadvantages
6. The gut
  1. Villi and microvilli give the gut a large suface area
  2. Villi have a good blood supply close to the surface
7. Exchange in plants
  1. Plants have stomata which allows them to get carbon dioxide
  2. Most water and ions needed are absorbed through the roots
  3. Transpiration is loosing water vapour through the plants stomata
Trasporting materials
1. Circulatory system
  1. Blood vessels, the heart and the blood
  2. Humans have a double circulation
  3. The heart pumps blood around the body
  4. Valves make sure blood flows in the right dirrection
  5. Arteries, veins and capillaries are all types of blood vessels
  6. Damaged heart valves can be replaced and stents can reopen blood vessels
2. Transport in the blood
  1. Blood plasma transports dissolved food molecules, carbon dioxide and urea.
  2. Red blood cells carry oxygen
  3. White blood cells are part of the immune system
  4. Platelets are used in clotting of blood
3. Artificial
  1. Artificial blood can be used to replace real blood that is lost
  2. No blood group matching is needed for artificial blood
  3. Artificial bood is very expensive and doesnt carry much oxygen
  4. Artificial hearts are good as there is no wait for a donor
  5. Artificial hearts can cause problems with blood clotting
4. Transport systems in plants
  1. Flowering plants have seperate transport systems
  2. Xylem tissue transports water and mineral ions
  3. Phloem tissue transports dissolved sugars from the leaves to the rest of the plants
Keeping internal conditions constant
1. Controling internal conditions
  1. Internal conditions must be kept constant to maintain the efficient use of organs and to prevent enzymes being denatured
  2. Carbon dioxide leaves the body through the lungs
  3. Urea is produced in the liver when excess amino acids are broken down
2. Kidneys
  1. Kidneys are important for homeostasis
  2. Kidneys produce urine by filtering the blood
  3. Excess ions, water and urea are removed in urine
3. Kidney replacements
  1. Dialysis does the job of a kidney but is not as effective
  2. Dialysis machines restore levels of dissolved substances to normal levels
  3. In kidney transplants, the old kidneys are left in the body
4. Body temperature
  1. Body temperature is controlled in the thermoregulatory center in the brain
  2. Body temperature must be kept at the level in which enzymes work best
  3. Blood vessels dilate and constrict to control blood flow to the skin and therefore heat loss
  4. Shivering heats up the body as blood goes to the muscles to move
5. Blood glucose
  1. Controlled by the pancreas
  2. Insulin allows glucose to move from the blood into cells
  3. Type 1 diabetes can be treated with injections of insulin before meals
  4. Type 2 diabetes can be treated with a careful diet and exercise
How humans can affect the environment
1. Population explosion
  1. The human population is growing rapidly and the standard of living is increasing
  2. We are using non renewable resources, taking over land and producing loads of waste
2. Polution
  1. Toxic chemicals can pollute the land, rivers and the air
  2. Carbon dioxide, sulfur dioxide and nitrogen oxide is realeased when fossil fuels are burnt
  3. Acid rain damages trees
  4. Air pollution contributes to global warming
3. Deforestation and peat destruction
  1. Large scale deforestation has led to an increase in cabon dioxide in the atmosphere
  2. The destruction of peat bogs releases carbon dioxide into the atmosphere
4. Global warming
  1. Carbon dioxde and methane levels are rising which is causing an increasd greenhouse effect
  2. Global warming is the increase in temperature of the surface of the earth
  3. Global warming causes climate change, rise in sea levels and loss of biodiversity
5. Biofuels
  1. Biofuels can be made using crops and fermenting them to make ethanol
  2. Biogas can be made by the anaerobic fermentation of plants and waste containing carbohydrates
  3. Biogas generators can be small to supply a family or big enough to supply a whole city
6. Sustainable food production
  1. Increasing efficiency of food production can be done by decreasing the number of stages in the food chain
  2. If you keep animals warm and stop them moving then they waste less energy
  3. Controlling net size and setting limits for the amount of fish that can caught conserves fish stocks
  4. The fungus fusarium is grown in sugar syrup to produce mycroprotein foods
7. Environmental issues
  1. Methods to produce food and water can have short and long term effects on the environment
  2. There is alot of data on effects on the environment

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