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===About Photosynthesis===
: [[Photosynthesis]] takes place in the [[chloroplast]].
: [[Chlorophyll]] is a [[catalyst]], for [[photosynthesis]] which is found in the [[chloroplast]]s, for of some [[eukaryotic Cell|eukaryotes]] and the [[cytoplasm]] of some [[photosynthesisbacteria]].
: Without [[chlorophyll]], [[photosynthesis]] cannot happen.
: When the [[leaf]] becomes [[dehydrated]] the [[Guard Cell|guard cells]] become [[flaccid]] causing the [[stomata]] to close. This prevents [[Carbon Dioxide]] from entering the [[leaf]]. This reduces the rate of [[photosynthesis]] so less [[water]] is used.
: When the [[leaf]] has enough [[water]] the [[Guard Cell|guard cells]] become [[turgid]] causing the [[stomata]] to open. This allows [[Carbon Dioxide]] into [[leaf]]. This increases the rate of [[photosynthesis]] so more [[water]] is used.
===Photosynthesis and the Atmosphere===
[[Photosynthesis]] removes [[Carbon Dioxide]] from the [[atmosphere]] and adds [[oxygen]] to the [[atmosphere]].
The [[atmosphere]] usually has these concentrations of gases:
{| class="wikitable"
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|[[File:AtmosphericGases.png|center|400px]]
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All living creatures [[respiration|respire]] and produce [[Carbon Dioxide]]. If there was no [[photosynthesis]] the amount of [[Carbon Dioxide]] in the [[atmosphere]] would increase and the amount of [[Oxygen]] in the [[atmosphere]] would decrease.
Before humans started [[Combustion|burning]] [[Fossil Fuel|fossil fuels]] [[photosynthesis]] and [[respiration]] kept the amount of [[Carbon Dioxide]] in the [[atmosphere]] constant but now that we burn [[Fossil Fuel|fossil fuels]] the amount of [[Carbon Dioxide]] is increasing.
{| class="wikitable"
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|[[File:CarbonCycle.png|center|500px]]
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| style="height:20px; width:200px; text-align:center;" |This [[diagram]] shows [[Carbon Cycle]] which shows how [[photosynthesis]] takes [[Carbon Dioxide]] out of the [[atmosphere]].
|}
Most [[Oxygen]] on Earth is made by [[algae]] '''photosynthesising''' in the oceans.
==Beyond the Curriculum==
{{#ev:youtube|https://www.youtube.com/watch?v=0UzMaoaXKaM}}