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Photosynthesis

Photosynthesis. Overview of Photosynthesis. All organisms need a constant supply of energy to survive. For most life on earth, the ultimate source of energy is the sun. Converting that energy source into something usable is accomplished by photosynthesis . Overview of Photosynthesis.

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Photosynthesis

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  1. Photosynthesis

  2. Overview of Photosynthesis • All organisms need a constant supply of energy to survive. • For most life on earth, the ultimate source of energy is the sun. • Converting that energy source into something usable is accomplished by photosynthesis.

  3. Overview of Photosynthesis • Photosynthesisis the overall process by which sunlight(solar energy) converts waterand carbon dioxide into chemical energy stored in glucose(sugar/carbohydrate). Oxygenis released as a waste product. • It can be represented by the following chemical reaction: Solar energy + Enzymes 6CO2 + 6H2OC6H12O6 + 6O2 Products = results Reactants = ingredients

  4. Structure of Chloroplast • Photosynthesis takes place in the chloroplast which has 2 main parts: • Grana: pancake-like stacks of thylakoid membrane • Stroma: fluid-like substance that fills the space between the grana

  5. Structure of a Chloroplast • Chloroplast: the organelle where photosynthesis takes place. • Most of the chloroplasts are in leaf cells. • Chloroplasts have 2 main areas: • Grana • Stroma

  6. Parts of the Chloroplast • Grana: stacks of thylakoid membranes • Thylakoid membranes are each individual coin-shaped compartment • Stroma: fluid that surrounds the grana

  7. Two Stages of Photosynthesis Photosynthesis can be divided into two sets of reactions: 1. Light-dependent (“photo”) • Requires sunlight and water (H2O ) • Takes place within & across the membrane of the grana/thylakoids. • 2. Light-independent (“synthesis”)uses energy from the light-dependent reactions to make sugars. • Does not require any sunlight • Occurs in the stroma of chloroplasts. • CO2is needed.

  8. Light-Dependent Reactions • Purpose: • To capture energy from the sun and store that energy in “energy-carrying molecules” (ATP and NADPH) • Location • Occurs in the grana (thylakoid membranes) where the chlorophyll is stored (chlorophyll is the pigment that captures sunlight)

  9. Light-Dependent Reactions • Chlorophyll absorbs energy from sunlight • Water molecules are split into hydrogen and oxygen. • Energy from sun is passed down the Electron Transport Chain (across the thylakoid membrane) and is stored in the bonds of ATP and NADPH • Oxygen is released as a waste product. • ATP, NADPH, and Hydrogen (H+) leave the grana and go into the stroma for the next stage!

  10. Light-Dependent Reactions

  11. Light-Independent Reactions/Calvin Cycle • Purpose: • To use the energy from the “energy-carrying molecules” (ATP and NADPH )from the light-dependent reaction to make sugar (glucose) • Location: • Occurs in the stroma

  12. Summary of the Light-Independent Reactions/Calvin Cycle • CO2is added. • Energy from the light-dependent reactions is used(from ATP and NADPH) • A simple sugar (glucose) is formed by combining hydrogen (from the water) and carbon dioxide.

  13. Light-Independent Reactions ATP/NADPH used to power light-independent reactions CO2 added to a 5-carbon molecule to form a 6-carbon molecule 6-carbon molecule, glucose, kicked out as end-product

  14. Chemosynthesis The process of an organism making its own food using chemicals (“chemo”) instead of sunlight (“photo”) like in photosynthesis. Example: Tubeworm Bush Song: • http://www.youtube.com/watch?v=lDwUVpOEoE4 • http://www.youtube.com/watch?v=g78utcLQrJ4

  15. Think about it… • How does the structure of a chloroplast allow for photosynthesis to occur? • How does energy travel from the sun to your body for you to use it?

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