I/GCSE Biology: The carbon cycle

Do you guys still remember the carbon cycle in I/GCSE Biology?

• Fixing – Absorbing carbon dioxide from the air and converting it into complex carbon compounds. Plants fix carbon dioxide during photosynthesis
• CO₂ molecule taken into leaf – during photosynthesis changed into organic carbon compound = glucose (carbohydrate) = fixing
• Removes carbon from physical environment
• Refer to I/GCSE Biology,  Glucose used for respiration = converted to CO₂ + released back into air
• Glucose may be changed into complex carbon compounds e.g. carbs, proteins & fats in plant tissue

In I/GCSE Biology,

• If plant eaten by animal – plant tissue broken down during digestion
• Some carbon compounds
  • absorbed through animals gut + made into carbs, proteins, fats etc. rest = faeces
  • converted to glucose for respiration then transformed to CO₂ – released into atmosphere
  • become part of animals body tissues or excreted in urine – animal eaten = same processes happen in that animal n
• Plant or animal not eaten = die and detritus feeders will feed on dead body
• Detritus feeder = an organism that feeds on detritus (decomposing organic waste)
  • Break down complex carbon compounds + use them to make more carbon compounds in their bodies – release carbon as CO₂ to air from respiration
• Decomposer organism e.g. fungi + B continue process of decay – do the same as arrow above

• Heat + pressure turns large quantities if organisms e.g. trees into fossil fuels
• Combustion of fossil releases CO₂ into air
• When carbon returned, leaf captures it and fixes it in photosynthesis – cycle starts again
• Constant cycling of carbon through carbon compounds in living organisms + CO₂ in air = carbon cycle
• Carbon cycle = the way in which carbon atoms circulate between living organisms and the physical environment
• Only nutrients and CO₂ continuously cycled – energy is captured by plants then transferred as heat to environment – energy can't be used by living organisms = no energy cycle
• Plants photosynthesise during day, take CO₂ from atmosphere. Plants respire all the time releasing CO₂ back into atmosphere

That's all~

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