Day 1 Flashcards
Photosynthesis
Process that uses sunlight as an energy source to complete ATP Synthesis and Synthetic Reactions.
Light Reactions
The pigment molecules are oxidized by light. NADP+ is reduced to NADPH in order to generate a proton gradient for ATP synthesis. Water is what reduces the pigment molecules and incidentally generates oxygen.
Dark Reactions
(Calvin Cycle) Takes the NADPH and ATP from the Light Reactions to reduce CO2 and incorporate carbon into three-carbon precursors of carbohydrates.
Chloroplast Structure
Outside membrane is highly permeable while the inside membrane is not. Inner membrane contains the stroma which intern conceals they tylakoid (stacked grana).
Photoreduction
During the Light Reactions, this synthesizes NADPH
Photophosphorylation
During the Light Reactions, this synthesizes ATP. This is the light-dependent generation of ATP.
Pigments and Light Absorption
Photosynthetic pigment absorb visible light. Small differences between pigments can dramatically change peak absorption. A=log(I./I) so the lower I the less light is transmitted through the sample and thus has the higher absorbance.
Chlorophyll
Like heme but has a magnesium ion instead of iron and another cyclic ring (Ring 5). Difference between plants and cyanobacteria is the saturation of Rings II and IV and the substituents in I, II, and IV
Carotenoids
An accessory pigment that is a linear polyene like b-carotene. In all green plants and most photosynthetic bacteria. Fall colors and carrots!
Accessory Pigments
In water-dwelling photosynthetic organisms they need pigments that will absorb something other than the blue and green (450-550) light that is absorbed by water. So, red algae and cyanobacteria use two linear tetraphyrroles: phycoerythrobilin and phycocyanobilin
Photosynthetic Reaction Centers
Where the primary reactions of photosynthesis take place. There are a lot more chlorophyll than RCs. So chlorophyll act as light-gathering antennas and pass energy from absorbed photons to the RCs. Transfer is fast and efficient. Without them RCs can only absorb one photon at a time.
Light Harvesting Complexes
Consists of arrays of membrane-bound hydrophobic proteins that contain numerous pigment molecules.
LH-2
In photosynthetic bacterium there is an integral membrane protein with eight a-subunits and b-subunits and 32 membrane bound pigment molecules. These are arranged and numbered to maximize efficiency of energy transfer between light harvesting complexes.
