Biology Unit2

  • Created by: Henryb
  • Created on: 30-04-15 19:11

Specialised Cells

Specialised Cells

  • Root hair cells - large surface area to absorb water and minerals easily.
  • Palisade cell - Has many chloroplasts for photosynthesis
  • White blood cell - The cell can change shape to engulf microbes
  • Sperm cell -  Tail to swim
  • Nerve cell - Has long nerve fibres to carry messages to other cells.
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Limiting factors of photosyntehsis

  • Temperature- A low temperature will limit the rate as the molecules will move less and therefore the reaction happens slower.Aslo photosynthesis is controlled by enzymes if the temperature becomes to high the enzymes 
  • Carbon dioxide- A shortage of C02 will limit the rate as fewer molecules will be available for the reaction.
  • Light intensity-  A shortage of light means there is less energy to power the reaction.Brighter light faster the rate of photosynthesis.


  • With no limiting factors, increasing a factor above a ceratin level will not increase the rate. All chlorophyll molecules are being used.
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Organisms in their environment

  • Temperature-e.g. samll artic plants- few herbivores survive in the area
  • Nutrients- Venus flytraps thrive where ther are low nitrate levels, because when they break down the animal protein.
  • Amount of light-animals and plants  only live in areas where day length and light intensity are right for them. In low light levels plants may have more chlorophyll and bigger leaves.
  • Availability of water-In the desert when it rains, plants grow and quickly sets seeds while the water is available .
  • Availability of carbon dioxide and oxygen-Water living organisms, invertabrates survive in water with low oxygen levels. Fish need high levels of dissolved oxygen.Mosiquitoes are attracted to us by the carbon dioxide we breathe out.
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Measuring the distribution of organisms

  • Size of area being studied
  • Number of organisms living there
  • Where the organisms live
  • representitve of the whole area




Eyes shut, throw randomly

Create a grid using tape, generate random numbers using a computer, for coordinates,


Line taken across habitat, at regular intervals, take note of the species touching the tape measure.

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