Photosynthesis Energy Life Energy the ability to do
Photosynthesis
Energy & Life § Energy = the ability to do work. § Where do we get energy from? § FOOD! § Plants are able to use light energy from the sun to produce own food = AUTOTROPH. § Organisms that obtain energy from food they consume = HETEROTROPH.
Energy § Energy can be stored in many forms – including chemical compounds. § The compound that cells use to store & release energy = Adenosine Triphosphate (ATP)
ATP § ATP contains: § 1. Adenine (base) § 2. 5 – Carbon sugar § 3. 3 Phosphate Groups § ATP = where energy is stored = currency of cell.
ADP § “Adenosine Diphospate” contains: § § 1. Adenine 2. 5 Carbon Sugar 3. 2 Phosphate groups ***When Phophate bond is broken, energy is released. ** ADP is made when energy stored in ATP is released to do work.
Photosynthesis § PURPOSE: Uses light energy to make sugars (food) & oxygen. § The equation: reactants 6 CO 2 + 6 H 2 O products C 6 H 12 O 6 + 6 O 2 energy in sunlight In words…. Carbon dioxide + water glucose + oxygen
PHOTOSYNTHESIS § 1. Plant cells have many organelles called chloroplasts. § 2. Photosynthesis occurs in a plant cell’s chloroplasts. § 3. It Occurs in 3 stages a. Energy is captured by plant’s pigments (chlorophyll) from sunlight b. The sun’s energy is then used to make ATP & NADPH c. Glucose is made in the Calvin Cycle using this ATP
The majority of photosynthesis occurs in the leaves!
Stage 1: Capturing the Sun’s Energy (light dependent) § 4. Occurs in the Chloroplast in small disks called thylakoids which contain the pigment chlorophyll. 5. Chlorophyll (pigment) traps energy from the sunlight
Stage 2: Using the Sun’s Energy to Form ATP § 6. After chlorophyll captures energy from the sun, the energy moves to the membrane of the thylakoid. l 7. In the thylakoid membrane, the energy is used to make ATP molecules.
Stage 3: Making Carbohydrates (glucose) (The Calvin Cycle) 9. ATP provides the activation energy to start the Calvin cycle (making carbohydrates) 10. Energy from ATP splits water molecules into H 2 & O. § Now have ADP & NADP+ as by products. 11. Hydrogen binds with Carbon atoms from CO 2 in the air to make glucose § (glucose = C 6 H 12 O 6) 12. Oxygen (O 2) is released into the atmosphere as waste for the plant
The Calvin Cycle
13. The Calvin Cycle assembles glucose monomers into polymers for energy use and growth. 14. Plants can store the sun’s energy in this carbohydrate form. 15. When a plant needs energy (food) to carry out life activities, chemical reactions break down the carbohydrates for energy that was made during photosynthesis. § ***Plants undergo photosynthesis AND cellular respiration!!!
§ 16. As long as ATP is available, this step (making sugars/calvin cycle) of photosynthesis can occur in sunlight or in the dark.
Photosynthesis Purpose Converts sunlight into glucose (carbohydrate) for food Where Reaction occurs Chloroplasts (thylakoids) Present in… Plants (some bacteria & protists) Reactants Carbon dioxide & water Products Oxygen, glucose Formula 6 CO 2 + 6 H 2 O energy in sunlight C 6 H 12 O 6 +6 O 2
Weird Plants!!! § Carnivorous plants such as the Venus fly trap and the pitcher plant still undergo photosynthesis! § They must get nitrogen from eating insects. Venus Fly Trap Pitcher plant
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