BIOL 111 Lecture Notes - Lecture 10: Light-Independent Reactions, Thylakoid, Porphyrin
Document Summary
In photosynthesis, electrons are stripped off water and transferred to co2 to reduce carbon to carbohydrate level. This requires a lot of energy and releases o2. Pigments- pick up wavelengths, built into thylakoid membrane, ex chlorophyll a/b, carotenoids. Carotenoids are used for high intensity light to prevent damage to pigments. When pigments absorb light, the electrons get excited. When electrons fall they go to the resonance transfer. Resonance transfer- energy coming down excites other electrons (train reaction) in neighboring molecules. Generates atp from adp + p (photophosphorylation) Forms sugar (3c) from co2 using atp and nadph. Chlorophyll a is at the reaction center, first time electrons are lost. During light reactions, there is a linear of cycle route. In p2, p680 loses an excited electron to another molecule (p680+ has a high affinity for electrons so it strips e- from h2o) Ps1 has p700+, its electrons are replaced by e- coming from p2, and so no water is split.
