Photosynthesis
Photosynthetic Reaction
Occurs in green chloroplasts
Needs light from Sun to convert carbon dioxide and water into
glucose and oxygen:
carbon dioxide+water (+light )−−−−¿ glucose+ oxygen
6 CO 2+ 6 H 2 O (+ light )−−−→C6 H 12 O6 +6 O 2
Note: this is a simplified equation for GCSE
Reactants and Products
Mainly occurs in leaves that face the sun as it requires light and
chlorophyll
o Palisade mesophyll has the highest number of chloroplasts so
complete majority of photosynthesis
Gases (including carbon dioxide) are absorbed through spaces
between spongy mesophyll cells
Water is absorbed by osmosis in root hair cells
o Transported by xylem around the plant in transpiration
Plants do photosynthesis to make glucose
Photosynthesis requires light (energy) so it is and endothermic
reaction
Glucose made gets transported to other cells by phloem in
translocation
Photosynthetic Algae
Algae can photosynthesize even though they are not plants
Many are microscopic (e.g. plankton) but some can be large (e.g.
giant kelp seaweed)
Some have evolved to contain other coloured pigments (e.g. brown)
About 70% of oxygen made in photosynthesis per day is from algae
in oceans
Rate of Photosynthesis
4 limiting factors in photosynthesis:
Carnivore – An organism that only eats animals
Chemical bonds – The attraction between atoms that holds them
together to form molecules
Deficiency – A lack or shortage
Endothermic reaction – A reaction that requires energy to be absorbed
to work
Herbivore – An organism that only eats plants
Limiting factor – Anything that reduces or stops the rate of a reaction
Photosynthetic Reaction
Occurs in green chloroplasts
Needs light from Sun to convert carbon dioxide and water into
glucose and oxygen:
carbon dioxide+water (+light )−−−−¿ glucose+ oxygen
6 CO 2+ 6 H 2 O (+ light )−−−→C6 H 12 O6 +6 O 2
Note: this is a simplified equation for GCSE
Reactants and Products
Mainly occurs in leaves that face the sun as it requires light and
chlorophyll
o Palisade mesophyll has the highest number of chloroplasts so
complete majority of photosynthesis
Gases (including carbon dioxide) are absorbed through spaces
between spongy mesophyll cells
Water is absorbed by osmosis in root hair cells
o Transported by xylem around the plant in transpiration
Plants do photosynthesis to make glucose
Photosynthesis requires light (energy) so it is and endothermic
reaction
Glucose made gets transported to other cells by phloem in
translocation
Photosynthetic Algae
Algae can photosynthesize even though they are not plants
Many are microscopic (e.g. plankton) but some can be large (e.g.
giant kelp seaweed)
Some have evolved to contain other coloured pigments (e.g. brown)
About 70% of oxygen made in photosynthesis per day is from algae
in oceans
Rate of Photosynthesis
4 limiting factors in photosynthesis:
Carnivore – An organism that only eats animals
Chemical bonds – The attraction between atoms that holds them
together to form molecules
Deficiency – A lack or shortage
Endothermic reaction – A reaction that requires energy to be absorbed
to work
Herbivore – An organism that only eats plants
Limiting factor – Anything that reduces or stops the rate of a reaction
