1 / 16

Photosynthesis

Photosynthesis. Energy and Life. Autotroph: organisms that make their own food Heterotrophs: organisms that obtain energy from the foods they consume To live, all organisms, including plants, must release the energy in sugars and other compounds. Chemical Energy and ATP.

glain
Download Presentation

Photosynthesis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Photosynthesis

  2. Energy and Life • Autotroph: organisms that make their own food • Heterotrophs: organisms that obtain energy from the foods they consume • To live, all organisms, including plants, must release the energy in sugars and other compounds

  3. Chemical Energy and ATP • ATP: (adenosine triphosphate) used by all cells as their basic energy source. • ATP consists of adenine, a 5-carbon sugar called ribose, and three phosphate groups. • The three phosphate groups are the key to ATP’s ability to store and release energy • ADP + P + energy  ATP

  4. Photosynthesis– plants use the energy of sunlight to convert water and carbon dioxide into high energy carbs. (glucose) and oxygen (waste)

  5. The Importance of Photosynthesis • The oxygen in the air comes from photosynthesis. The plants continue to replenish the oxygen in the air. • All of our food comes directly or indirectly from photosynthesis.

  6. The Photosynthesis Equation • The overall reaction is: 6CO2 + 6H2O LIGHT> C6H12O6 + 6O2 OR Carbon Dioxide + Water light> Glucose + Oxygen

  7. The Reactions of Photosynthesis • Remember it all occurs in the chloroplast. • Thylakoids – sac-like photosynthetic membranes inside chloroplasts, arranged in stacks called grana • Photosystems – clusters of pigments in thylakoid • Stroma – region outside of the thylakoid membrane (Calvin Cycle takes place)

  8. Light • Photosynthesis uses visible light • Only visible light with intermediate wavelengths has enough energy to cause chemical change without destroying biological molecules.

  9. Pigment • Pigments – molecules that collect light • Each pigment absorbs a particular wavelength of light in the visible spectrum • The main photosynthetic pigment is chlorophyll. • Two types chlorophyll a and chlorophyll b • Accessory pigments: • Carotenoids • Anthocyanins– not photosynthetic

  10. Pigment Absorption

  11. How it works • Light is a form of energy • When cholorphyll absorbs light, much of the energy is transferred directly to electrons in the molecule • The raising of the energy levels of these electrons makes photosynthesis work

  12. Electron Carriers • Electron carriers are used to transport high-energy electrons from chlorophyll to other molecules • NADP+ (nicotinamide adenine dinculetotide phosphate) • Accepts and hold two high energy electrons and a hydrogen ion (H+) • Makes NADPH

  13. Stage of Photosynthesis 1. 2.

  14. Light Reactions • Requires light • Produces ATP and NADPH and oxygen gas • ATP synthase is a membrane protein • Allows H+ ions to pass through the cell membrane • Transforms ADP into ATP • Think of the light reaction, as a process by which organisms "capture and store" radiant energy as they produce oxygen gas.

  15. The Dark Reactions • The dark reactions take place outside the thylakoid membrane. • Uses ATP and NADPH and CO2 from the light reaction to produce high energy sugars (glucose) • Carbon dioxide is broken and “fixed” into glucose or fructose molecules in the CALVIN CYCLE!

  16. Factors Affecting Photosynthesis • The amount of water • Temperature. • Best between 0 and 35 ºC. • Intensity of light

More Related