Some Photosyntesis Basics

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Transcript Some Photosyntesis Basics

Some Photosynthesis Basics
• Green-coloured pigment
• Absorbs light energy
• There are several types, two common ones
being “a” (blue-green) and “b” (yellow-green)
Chlorophyll composition
• Porphyrin ring attached to a long
hydrocarbon chain
• Magnesium atom at centre of ring
• Delocalized electrons in alternating
single/double rings absorb light energy
• Hydrocarbon chain is hydrophobic so
anchors it into membrane
Overall reaction of photosynthesis:
6CO2 + 6H2O + light energy  C6 H12O6 + 6O2
** note: it’s not always glucose that is made…. So this is just a general equation**
• The Photosynthetic organs of plants
• Structure maximizes surface area exposed to sunlight and limits
distance gases (CO2 ) have to travel
• Have a waxy cuticle to protect from over-absorption of
water/excessive sunlight
• Have special photosynthetic cells called mesophyll
• Have “guard cells” that create tiny openings called stomata that
regulate exchange of CO2 and oxygen and allow water vapour to
enter or escape by transpiration
• Have Vascular bundles (“veins”) that transport water and minerals to
roots and leaves and carry carbohydrates from the leaves to the