Biology 203 1st Edition Lecture 24 Outline of Last Lecture I. Photosynthesis vs. RespirationII. Where does photosynthesis occur?III. Light ReactionsIV. PhotolysisOutline of Current Lecture I. Light- Independent ReactionsII. Calvin Cyclea. Fixation Stageb. Reduction Stagec. Regeneration StageIII. After photosynthesisIV. Starch StorageCurrent LectureI. Light-Independent Reactionsa. CO2 is fixed in Calvin Cycleb. The enzyme Rubisco fixes CO2 into an organic compoundII. Calvin Cyclea. Fixation Stagei. Incorporating carbon from the airii. Enzyme called Rubisco catalyzes reaction between a 5C sugar and CO2, producing two 3C moleculesiii. This type of photosynthesis is called “3C photosynthesis” for this reasonb. Reduction Stagei. Requires energy input (from ATP) and electrons (from NADPH)ii. Produces the compound glyceraldehyde 3-phosphate (G3P)1. Starting point for carbohydrate synthesis, e.g. glucose for celluloseand starch2. Starting point for biosynthesis of everything else in their bodies too: oils, proteins, DNA, secondary compounds etc.iii. But only 1/6 of G3P produced goes into biosynthesisc. Regeneration Stagei. 5/6 of the G3P a plant produces in Calvin cycle is used to regenerate the 5C sugar that Rubisco reacts withThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ii. Pretty fancy biochemistry: five 3C molecules rearranged to make three 5Cmoleculesiii. Consumes some more ATP from light reactionsIII. After photosynthesisa. After extracting the sugar from the chloroplast, the plant cytosol makes a living the same way animal cells dob. Plant cells that can’t do photosynthesis import sucrose from the cells that can, and then do respirationc. Only the green parts of a plant can do photosynthesis, and even then, they can only do that during the dayIV. Starch storagea. During the day, the leaves need to produce enough sugar to feed the rest of the plant, and also store enough starch to keep the whole plant alive during the nightb. Many plants also store starch in other organs (after being transported from the photosynthetic
View Full Document