BIO 101 1st EditionLecture 14Outline of Last LectureI. Cellular RespirationII. Redox Reactionsa. Oxidationb. ReductionIII. Four Stages of Respirationa. Glycolysisb. Transition to Mitochondriac. Krebs Cycled. Oxidative PhosphorylationOutline of Current LectureI. Fermentationa. Products of glycolysisII. RespirationIII. Photosynthesisa. Calvin cycleb. Light reactionsChapter 9 cont.Fermentation- anaerobic catabolism of organic nutrients. Glycolysis plus one or 2 more chemical reactions to regenerate NAD+ (oxidized form of coenzyme)Products of glycolysis2 ATPs2 pyruvates2 NADHIf O2 was present, NADH would cash in electrons at electron transport chain and generate more ATP (also regenerate NAD+)- In absence of O2- cant run the electron transport chain (because you NEED O2 as the final electron acceptor)- So how can the cell regenerate NAD+ so that it can continue glycolysis?- Electrons from NADH are transferred back to make one of two unique products:1. Lactic acid2. Ethanol- No ATP is generated by transferring electrons to pyruvate, but it regenerates NAD+ so that glycolysis can continue.- Energy yield from fermentation=2 ATP/glucose- 2 examples of fermentationo Ethanol fermentation is used by yeast to make beero Muscle cells that don’t get enough O2 do lactic acid fermentation= sore musclesBIO 101 1st EditionChapter 10- Photosynthesis- We have been talking about respiration overall equation- Photosynthesis is the opposite, with regard to the overall equation and energy- Major goal of respiration=convert stable chemical energy (food) into readily useable form (ATP)- Major goal of photosynthesis= convert light energy into stable chemical energy (make food)- Although the goals are opposite, the two processes share many mechanisms in common- Photosynthesis is an important process- all living things depend on it- photosynthetic organisms are at the bottom of the food chain. They make their own food, all other things have to eat other living things to stay alive- Autotrophs= “self feeders”- produce food- PRODUCERSHeterotrophs= cannot produce own food, rely on food produced by other living things CONSUMERS- Plants are photoautotrophs- make their own food using photosynthesis- Plants ALSO do respiration (i.e. they make their own sugar and then use respiration to convert it to ATP_- Animals (including humans) cannot do photosynthesis. They ONLY do respiration. - Photosynthesis occurs on organelle called the chloroplast- it has 2 layers of membrane - Photosynthesis occurs in TWO STAGES1. Calvin cycle2. Light reactions ATP (energy)+ NADPH (source of electrons)- The two stages are interconnected:Calvin cycle uses CO2 to make sugar= i.e. takes a simple, highly oxidized molecule and makes a complex, highly reduced molecule)CO2 sugarBIO 101 1st EditionSimple needs energy complexOxidized needs energy reduced- The ATP and electrons for the Calvin cycle are produced during the light
View Full Document
Unlocking...