Lab #7 – Bio 101 Photosynthesis

Reminder: Photosynthesis is the opposite of respiration Endergonic – absorbing energy Transforms radiant energy to chemical energy Exergonic – releasing energy Transfers one type of chemical energy to another (ATP)

Ecological Implications Photosynthesis converts 100 billion metric tons of atmospheric carbon into biomass every year; captures 6x more energy than humans use!

How does photosynthesis work?

Light and dark reactions – inputs and outputs

Evolution of photosynthesis - endosymbiosis Evolved at least 2.5 billion years ago! Mitochondria  aerobic proteobacterium Chloroplasts  Cyanobacteria

Evolution of photosynthesis - endosymbiosis Evolved at least 2.5 billion years ago! Mitochondria  aerobic proteobacterium Chloroplasts  Cyanobacteria Note the similarities:

Photosynthesis in other organisms Oriental hornet – evolved adaptation to harvest solar energy using yellow xanthopterin pigment… very similar to plants! Bacteria – Different inputs/outputs, but similar processes.

Pigments make it all possible

Pigments absorb the sun’s radiant energy Pigments serve a range of functions: Chlorophylls – maximum photosynthesis Carotenoids – Extendeds range of wavelengths, protects chlorophylls Anthocyanins – attractor for pollinators, sunscreen, protection from herbivory/cold (?)