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Photosynthesis Chapter 8.

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Presentation on theme: "Photosynthesis Chapter 8."— Presentation transcript:

1 Photosynthesis Chapter 8

2 Section 8.1 Energy and life

3 Chemical energy and atp
What is energy? - The ability to do work What are some uses of energy? - build new molecules - contract muscles - carry out active transport Life depends on the ability to obtain and use energy

4 Chemical energy and atp
What are some forms of energy? - light, heat, and electricity Energy can be stored in chemical bonds (ex. Wax melting. Explain example in class- write down). When energy is lost, it is released as heat

5 Chemical energy and atp
Living things use chemical fuels to store and release energy, such as: - adenosine triphosphate (ATP), which is used by cells. ATP composition (make up) - adenine - 5-carbon sugar (ribose) - three phosphate groups ( key to storing and releasing energy)

6 Storing energy What do cells use to store energy? - Adenosine diphosphate (ADP) - ADP has two phosphate groups instead of three like ATP. How? - When cells have energy available, it can store small amounts by adding phosphate groups to the ADP molecule, making ATP.

7 releasing energy How is energy released in cells? - By breaking the bonds in ATP between the second and third phosphate groups. ATP can release and store energy by breaking and re-forming the bonds between its phosphate groups, which makes ATP useful energy source for all cells.

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9 Biochemical energy How do cells use ATP energy?
- carry out active transport Process Cell membranes have a sodium-potassium pump. Membrane proteins pump sodium ions (NA+) out of the cell. Potassium is pumped into the cell. ATP provides the energy (E) that helps the membrane maintain homeostasis (balance). ATP energy also provides E for cilia and flagella to function. Synthesis of proteins (making of proteins)

10 Biochemical energy How much ATP is in cells? - small amounts
- enough for cells to use for activity (seconds only) Is ATP good for storing large amounts of energy over a Long period of time? - no How can cells keep ATP for a source of energy? - by regenerating ATP from ADP as needed by using food like glucose.

11 Heterotrophs and autotrophs
Cells do not automatically supply ATP. They must get ATP from a source, but what sources? Heterotrophs Autotrophs Photosynthesis Organisms that obtain food by consuming (eating) other living things Organisms that make their own food. How autotrophs use the energy of sunlight to produce high-energy carbohydrates, sugars and starches that can be used as food. Humans, animals Plants, algae, bacteria Plants convert energy from the sun into chemical energy stored in the bonds of carbohydrates

12 Chloraphyll and chloroplasts
In order for photosynthesis to occur, light from the sun must be captured. LIGHT 1. How does energy from the sun travel to earth? - In the form of light 2. What is light made of? - a mixture of wavelengths - we see wavelengths in a spectrum 3. Wavelength spectrum can be viewed in several colors - red, orange, yellow, green, blue, indigo, and violet

13 Chlorophyll and chloroplast
PIGMENT 4. How do plants gather the sun’s energy? - they use PIGMENTS (photosynthetic organisms use pigments for sunlight energy absorption) 5. What is a pigment? - light absorbing molecule 6. What is the plants principal(main) pigment? - CHLOROPHYLL 7. There are two (2) types of chlorophyll - chlorophyll a and b - both absorb light best in the blue-violet, and red spectrum regions, and worst in the green spectrum.

14 Chlorophyll and chloroplast
PIGMENT 8. What makes plants look green? - the reflection of green light by leaves. 9. What other pigments do plants have? - CAROTENE ( an accessory pigment), which is a red and orange pigment - carotene absorbs light in the other regions of the spectrum 10. When temperature falls, the chlorophyll breaks down, leaving the red and orange pigments visible (Why leaves are red and orange during the fall)

15 Chlorophyll and chloroplast
CHLOROPLASTS 11. Photosynthesis takes place inside the chloroplast 12. What are the parts of the chloroplast? - THYLAKOIDS = saclike photosynthetic membranes that are interconnected and arranged In stacks. - The stacks of thlylakoids are called GRANA - CHLOROPHYLL pigments are located inside the thylakoids - STROMA= the fluid portion of the chloroplast

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17 Chlorophyll and chloroplast
ENERGY AND COLLECTION 13. Why is chlorophyll so important? a. chlorophyll absorbs light very well. b. large portions of the light absorbed is transferred to electrons (located in the chlorophyll). c. high-energy is made by increasing the energy levels of the electrons , which make photosynthesis possible. Sunlight absorbed Electrons high energy electrons Photosynthesis

18 High energy electrons NADP+ 14. How do plants carry high-energy electrons from the chlorophyll to other molecules in the plant? - they use electron carrier molecules * Electron carriers can accept a pair of high-energy electrons and transfer them, along with most of their energy to other molecules* 15. NADP+ (nicotinamide adenine dinucleotide phosphate) is a carrier molecule

19 High energy electrons NADP+ 16. What is the process of NADP+? A. accepts/holds 2 high-energy electrons + Hydrogen ion (H+) B. Converts NADP+ NADPH (traps energy in chemical form) C. NADPH carries high-energy electrons (produce in chlorophyll) to chemical reactions in the cell

20 photosynthesis 17. What is photosynthesis? - the process of plants using energy from the sunlight to convert water and carbon dioxide (reactants) into high- energy sugars and oxygen (products) 18. The plant uses the sugars to produce: carbohydrates (starches) provide energy to make proteins and lipids 19. What is the chemical reaction for photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2 (REACTANTS) (PRODUCTS) 6 Carbon Dioxide + 6 Water Sugar + 6 Oxygen

21 photosynthesis There are two steps in the process of photosynthesis. LIGHT –DEPENDENT REACTION a. This is the first set of reactions. b. Requires direct light, and pigments c. Uses sunlight's energy to make ATP d. Reaction takes place within the Thylakoids e. Water is required (source of electrons), and Hydrogen ions (H+) f. The gas released as a byproduct is OXYGEN

22 LIGHT –INDEPENDENT REACTION
photosynthesis LIGHT –INDEPENDENT REACTION Plants absorb CO2 from the atmosphere to complete photosynthesis and produce carbon-containing sugars and other carbohydrates Process ATP and NADPH molecules produce high-energy sugars from carbon dioxide (CO2) and water H2O. No light is required. Reaction takes place in the stroma (fluid portion of the chloroplasts). Known as the Calvin Cycle

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24 Section 8.3 the process of photosynthesis

25 Light –dependent Reactions
Four (4) steps in light dependent reaction - photosystem II - Electron Transport Chain - photosystems I - ATP formation

26 Light –dependent Reactions
The Light-Dependent reactions use energy from the SUN to produce: 1. OXYGEN 2. Convert ADP ATP Convert NADP NADPH 3. What are the proteins in Thylakoids called? PHOTOSYSTEMS 4. Photosystems are surrounded by accessory pigments.

27 Light –dependent Reactions
PHOTOSYSTEMS 5. What is the purpose of a photosystem? Absorb sunlight and generate high-energy electrons. 6. There are two photosystems called PHOTOSYSTEM I AND PHOTOSYSTEM II

28 Light –dependent Reactions
PHOTOSYSTEM II 7. Light Energy is absorbed turns into high-energy electrons 8. Water molecules are split and replace the electrons 9. H+ ions and oxygen is released

29 Light –dependent Reactions
ELECTRON TRANSPORT CHAIN 10. High energy electrons move down the (ETC) to the PHOTOSYSTEM I. 11. The energy generated (made) is used to pump H+ ions across and into the thylakoid membranes.

30 Light –dependent Reactions
PHOTOSYSTEM I 12. Electrons are reenergized 13. A second electron transport chain transfers the reenergized electrons to NADP+ making NADPH

31 Light –dependent Reactions
ATP Formation 14. Thylakoid membrane become positively (+) charged (as a result of the H+ ions). 16. ATP Synthase - Pass H+ ions back across the thylakoid membrane - Converts ADP ATP

32 Light –independent Reactions
Processes of Light- Independent Reactions the CALVIN CYCLE - Carbon Dioxide - Sugar Production

33 Light –independent Reactions
During the light-independent reaction (Calvin Cycle), ATP and NADPH from the light-dependent reactions produce high-energy sugars

34 Light –independent Reactions
CARBON DIOXIDE CO2 enter the Calvin Cycle from the atmosphere. 6 CO2 molecules (atmosphere)+ 5-carbon compounds (inside chloroplast) carbon compounds produce For every 6 CO2 molecules that enter the cycle = twelve 3- carbon compounds are produced. Energy from ATP and NADPH convert the carbon compounds into HIGHER ENERGY

35 Light –independent Reactions
SUGAR PRODUCTION Two of the twelve (12) 3-carbon molecules are removed. The two 3-carbon molecules are used by the plant to produce: - sugars - lipids - amino acids 3. The remaining ten (10) 3-carbon molecules back to 5- carbon molecules

36 Light –independent Reactions
SUGAR PRODUCTION

37 Light –independent Reactions
CALVIN CYCLE SUMMARY Energy for the reactions comes from the light-dependent reaction. 6CO2 makes carbon sugar The sugars are used for energy, growth and development by the plant Make lipids, proteins, carbohydrates (cellulose)

38 Light –independent Reactions
RESULTS Light-dependent reaction – traps the ENERGY from the SUNLIGHT in what form? - CHEMICAL FORM 2. Light-independent reaction – uses CHEMICAL ENERGY to make : - high –energy sugars - water

39 The end


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