5.6.1 interrelationship between photosynthesis & respiration

light energy from sun transformed into chemical energy & can be used to synthesise large organic molecules from smaller inorganic molecules

organisms that use energy to synthesise large organic molecules from smaller inorganic molecules

organisms that rely on other plants/animals to obtain energy

organisms which use light energy to synthesise large organic molecules from smaller inorganic ones

• photoautotroph • producers

6CO2 + 6H20 + energy from protons —-(chlorophyll)—> C6H12O6 + 6O2

carbon fixation (carbon dioxide converted into sugars)

• endothermic = requires energy • needs electrons

C6H12O6 + 602 —–> 6H2O + 6CO2 + energy

• both important for cycling carbon dioxide & oxygen • products of one process are raw materials for other process (aerobic respiration removes oxygen & adds carbon dioxide, photosynthesis does the opposite)

respire = 24/7 photosynthesise = daylight

to allow photosynthesis at a rate which will replenishes carbohydrates stores used up by respiration

when photosynthesis & respiration proceed at the same rate, so no net gain or loss of carbohydrate

the time a plant takes to reach the compensation point 9 (different for different species)

can utilise lower intensity of sunlight & reach compensation point sooner

require higher light intensity to achieve optimum rate of photosynthesis