Lab #7 – Bio 101Photosynthesis

Reminder: Photosynthesis is the opposite of respiration

Endergonic – absorbing energyTransforms radiant energy to chemical energy

Exergonic – releasing energyTransfers one type of chemical energy to another (ATP)

Ecological ImplicationsPhotosynthesis 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 proteobacteriumChloroplasts Cyanobacteria

Evolution of photosynthesis - endosymbiosis Evolved at least 2.5 billion years ago!Mitochondria aerobic proteobacteriumChloroplasts 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 make it all possible

Pigments absorb the sun’s radiant energy

Pigments serve a range of functions:

Chlorophylls – maximum photosynthesisCarotenoids – Extendeds range of wavelengths, protects chlorophylls Anthocyanins – attractor for pollinators, sunscreen, protection from herbivory/cold (?)