MCB 181R Lecture Notes - Lecture 9: Light-Independent Reactions, Photosystem I, Rubisco
21 Nov 2014
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Document Summary
Photosynthesis: biochemical process for building carbs (used as structural component of plants & e source to make atp) from sunlight & co2 taken from the air. Core concept 8. 1 photosynthesis is the major pathway by which e & c are incorporated into carbs. Building carbs requires input of e (from sun) Series of redox rxns where e- passed = photosynthetic e- transport chain, which begins w/ absorption of light by photosystems. Movement of e= used to make atp & nadph, which are used to make carbs using co2 (calvin cycle) Evolutionary history of synthesis includes both horizontal gene transfer & endosymbiosis. Most ancient forms of photosynthesis have simple photosynthetic e- transport chains w/ a single photosystem; must use more easily oxidized compounds which are only abundant in certain environments. Cyanobacteria were 1st to pull e- from h2o w/ 2 photosystems. Alt hypothesis is bacteria w/ single photosystem obtained 2 by horizontal gene transfer & later became chloroplasts by endosymbiosis.
