Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 8: The Working Cell: Energy from Sunlight Concept 8.1: Photosynthesis Uses Light Energy to Food I. The Structure of Chloroplasts A. Photosynthesis takes place in the chloroplast B. Chloroplasts contain compounds called pigments that give leaves their color (chlorophyll). C. Leaves contain the most chloroplasts. (fig. 8-2) D. Stoma are tiny pores that allow carbon dioxide to enter and oxygen to leave the plant cell. E. Veins (xylem) carry CO2 and H2O from the plants roots to the leaves and deliver(phloem) organic compounds to other parts of the plant. F. The inner membrane of a chloroplast encloses a thick fluid called stroma. G. Suspended in the stroma are many disk shaped sacs called thylakoids which are arranged in stacks called grana. H. These stacks organize the series of reactions that make up photosynthesis. II. Overview of Photosynthesis A. In cellular respiration, electrons “fall” from glucose to O2 to release energy. B. In photosynthesis, electrons from water are boosted “uphill” (potential) by the energy of sunlight. C. These excited electrons, along with carbon dioxide and hydrogen ions to produce C6H12O6 molecules D. Photosynthesis occurs in two main steps: Light and Calvin Cycle (Dark Reaction). III. The Light Reactions A. Light Reactions convert the energy in sunlight to chemical energy. B. Chloroplasts use captured light energy to remove electrons from H2O, splitting it into oxygen and hydrogen ions. C. The electrons and hydrogen ions are used to make NADPH, which is an electron carrier. D. Chloroplasts also use the captured light energy to generate ATP. E. The overall result of the light reactions is the conversion of light energy to chemical energy stored in NADPH and ATP IV. The Calvin Cycle A. Calvin Cycle makes sugar from the atoms in carbon dioxide plus the hydrogen ions and high energy electrons carried in NADPH B. The ATP made in the light reactions provides the energy to make sugar. C. The Calvin cycle is sometimes referred to as the “light-independent reactions” because it does not require light energy to begin. Overview fig. 8-4