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  • Created by: KatieR17
  • Created on: 07-02-16 21:04

B3 1.1 - 1.3

1.1 Osmosis

  • osmosis is the diffusiom of water
  • water diffuses from a dilute solution to a more concentrated soloution through a partially permeable membrane 
  • water moves into or out of cells by osmosis throgh the cell membrane 

1.2 Active Tansport

  • active transport allows clls to take in sunstances against a concentration gradient 
  • active tansport uses energy from respiration 
  • ions can from dilute solutions, and other substances such as sugar can be absorbed by active transport.

1.3 The Sports Drink Dilemma 

  • most soft drinks contain: water to replace water when lost when sweating; sugar to replace sugar used for energy release in exercise; mineral ions to replace those lost in sweating 
  • for normal levels of exercise, water is likely to be as effective as a sports drink.
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B3 1.4 - 1.6

1.4 Exchanging Materials - The Lungs

  • large organisms need exchange surfaces
  • exchange surfaces have features to make them efficient
  • the lungs are adapted to be an efficent echange surface

1.5 Ventilating the Lungs

  • the breathing system is designed to move air im and out of the lungs
  • ventilation occurs due to changes of pressure inside the chest

1.6 Artificial Breathing Aids

  • Reasons for artifical breathing aids: if the alveoli are damaged the surface area for gas exchange is reduced: if the tubes leading to the lungs are narrowed, less air can be moved through them: if the person is paralysed their muscles will not work to pull the ribcage up and out
  •  breathing aids which force measured amounts of air in the lungs use positive pressure
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B3 1.7 - 1.9

1.7 Exchange in the gut

  • the villi are an efficient exchange surface for the absorption of the soluble products of digestion by diffusion or active transport
  • villi provide a large surface area and have a good blood supply.

1.8 Exchange in plants

  • the stomata in plant leaves allow carbon dioxide to diffuse into the leaf from the atmostphere 
  • leaves are flat and thin with internal aire spaces to increase the surface area for diffusion of gases
  • root hair cells increase the surface area of roots.

1.9 Transpiration

  • water is lost from the leaves be evaporation
  • the water vapour escapes the leaf through the stomata when the open to allow carbon dioxide to enter the leaf
  • wilting can protect the leaf from excessive water loss. 
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B3 2.1 - 2.3

2.1 The circulatory system and the heart

  • the double circulation system in humans consists of blood vessels, blood and the heart
  • the heart is the organ that pumps blood around the body
  • valves prevent backflow of blood

2.2 Keeping the blood flowing 

  • arteries, viens and capillaries are the main types of blood vessel
  • substances diffuse between the blood and the cells in the capillaries 
  • blocked or narrow arteries can be widened by stents, damaged heart valves can be replaced

2.3 Transport in the Blood

  • blood plasma transports dissolved food molecules, Co2 and urea. Plasma also contains blood cells.
  • the red blood cells carry oxygen from the lungs to the cells. the white cells are part of the defence system
  • plateles are invloved in blood clotting.
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B3 2.4 - 2.5

2.4 Artifical or real?

  • there are advantages and disadvantages when using artificial blood and artificial hearts
  • they are useful when real blood or donor hearts are not available 

2.5 Transport systems in plants

  • flowering plants have two transport tissues
  • xylem transports water and mineral ions from the roots to the stems and the leaves
  • phloem transports food, such as dissolved sugar, from the leaves to other parts of the plant.
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B3 3.4 - 3.6

3.4 Kidney transplants

  • a diseased kidney can be replaced by a healthy kidney
  • the donor kidney must be a very good 'match'
  • the immune system has to be suppressed or it is likely to reject the new kidney.

3.5 Controlling body temperature

  • enzymes work in a very narrow temperature range
  • body temperature is monitored and controlled to kepp it within this narrow range.

3.6 Treatment and temperature issues

  • both dialysis and kidney transplats have advantages and disadvantages 
  • see AQA Science Biology Revision Guide for more information (page 86)
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B3 3.7 - 3.8

3.7 Controlling blood glucose 

  • the level of glucose in the blood is controlled by hormones
  • in type 1 diabetes the blood glucose level risesto high levels because it is not controlled properly.

3.8 treating diabetes

  • type 1 diabetes is treated with insulin injections
  • new methods are being tried or developed to treat diabetes. 
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B3 4.1 - 4.4

4.1 the effects of the population explosion

  • the human poulation is increasig rapidly
  • humans are using more resources and producing more waste and pollution

4.2 land and water pollution

  • humans are responsible for pulling both land and waterways

4.3 air pollution

  • sulfur dioxide dissolved in rain makes it more acid
  • acid rain can effect organisms both directly and indirectly

4.4 deforestation and peat destruction

  • forest are cut down to clear land for farming
  • deforestation leads to a reduction in biodiversity and an increase in CO2 in the atmostphere
  • destruction of peat bogs also releases carbon dioxide
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B3 4.5 - 4.7

4.5 Global warming

  • the climate of the Earth is getting warmer
  • global warming affects living organisms.

4.6 Biofuels

  • ethanol based fuels can produced by anaerobic fermentation of sugars from plants
  • the ethanol ditilled from the fermentation prduct can be used as fuel in motor vehciles

4.7 Biogas

  • boigas is mainly methane. it is made by the anaerobic ferentation of a wide range of waste substances and plant material containing carbohydrates.
  • biogas can be made on a large or a small scale
  • many different microorganisms are involved in biogas production
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B3 4.8 - 4.10

4.8 making food production efficient 

  • short food chains make food production more efficient
  • food production can be controlled to reduce energy wastage

4.9 sustainable food production

  • fish stocks can be maintained by controlling fishing quotas and net size
  • the fungus fusarium produces mycoprotein

4.10 environmental issues

  • human activities affet both local and global environments
  • there is alot of evidence for environmental change
  • scientists need to check the validity and the reproducibility of the data collected.
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