Meeting 5

organism that cannot fix carbon and uses organic carbon for growth

an organism that produces complex organic compounds (carbohydrates, fats, and proteins) from simple inorganic molecules using energy from light (by photosynthesis)

1) absorbtion of light + formation of a high energy electron (?) & formation of O₂ to H₂O

2) reduction of NADP+ to NADPH b/c of electron transport, and the generation of proton motive force

3) ATP is made

4) carbon fixation: conversion of CO₂ into carbs

• -this is done by chlorophylls attached to thylakoid (3rd) membrane; specifically the multiprotein complex PSII
• -the energy from light is used to remove electrons from water (e- donor for green plants)
• -and are transfered to quinone Q (primary e- acceptor)

where the oxidation of water to molecular oxygen takes place

chlorophyll of choice: P680

consist of porphyrin ring attached to hydrocarbon side chain (phytol tail); has a central Mg⁺ ion + additional 5-carbon ring!

• -want the phytol tails (CH) so the chlorophyll can attach to hydrophobic regions of membrane proteins/attach to membrane
• -want the Mg (metal) b/c they have physical states in which e- can be propelled outward then drop back = energy released

• -e- accepted by the quinone (primary e- acceptor) move through a series of carriers until they are 'terminally' accepted by NADP+...this reduces it to NADPH
• -that takes place in PSI

• -coupling: e- transport across thylakoid membrane is COUPLED with proton movement FROM the stroma TO inside the thylakoid lumen
• -this means the pH_lumen < pH_stroma

reduces the electron carrier NADP+

chlorophyll of choice: P700

• -the movement of protons DOWN their concentration gradient
• -from the thylak lumen TO the stroma (high H+ to low)
• -this happens through the F₀F₁ complex
• -is coupled with the synthesis of ATP from ADP * Pi

• -Calvin cycle
• -now there's ATP and NADPH in the system
• -these high energy molecules drive the construction of 6-carb sugar polymers from CO₂ and H₂O

stacks of thylakoids

a stroma thylakoid is a thylakoid membrane that ISN'T stacked

fluid inside the chloroplast; located outside the thylakoid

3rd inner membrane in a chloroplast

.03%; enough to sustain all life

responsible for being able to pull e-'s off the high electronegative molecular oxygen? water?

• that's how we make ATP
• ex. the plant might have enough carbs, but still needs ATP for a physiological function

• to adjust the wavelength of absorbed light, like to be able to absorb more light of different wavelength
• -especially useful for different times in the day (at the end of the day there's more red light = longer wavelength)

- shuttling is phosphorylation dependent