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Photosynthesis & Respiration. What is Photosynthesis? The process of photosynthesis is a chemical reaction. It is the most important chemical reaction.

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Presentation on theme: "Photosynthesis & Respiration. What is Photosynthesis? The process of photosynthesis is a chemical reaction. It is the most important chemical reaction."— Presentation transcript:

1 Photosynthesis & Respiration

2 What is Photosynthesis? The process of photosynthesis is a chemical reaction. It is the most important chemical reaction on our planet.

3 What is the equation for the chemical reaction of photosynthesis?

4 Six molecules of carbon dioxide react with six molecules of water to form 1 molecule of glucose and six molecules of oxygen.

5 Describe Photosynthesis The process of changing light energy to chemical energy Energy stored as sugar Occurs in plants and some algae Plants need light energy, CO 2, and H 2 O Takes place in the chloroplasts, using chlorophyll, the green pigment in plantschloroplasts chlorophyll

6 two parts photosynthesis What are the two parts of photosynthesis? the light reactionthe light reaction requires light must be first requires light and must be first the light-independent reactionthe light-independent reaction does not require light follow but must follow the light reaction TRIVIA: This used to be called the dark reaction. Why is not used today?

7 What happens during photosynthesis? Plants capture light energy and use that energy to make glucose Sunlight provides the energy needed by chlorophyll to change molecules of carbon dioxide and water into glucose Oxygen is also released in this reaction

8 The Light Reaction 1.Chlorophyll is energized 1.Chlorophyll is energized by sunlight splitswater 2.The energy splits a water molecule oxygen 3.A. The oxygen is released Energy B. Energy is stored by hydrogen(NADPH) and ATP

9 The Light-Independent Reaction 1.Carbon dioxide combines with RuBP to form PGA 2.PGA is converted to PGAL (G3P) 3.PGAL (G3P) can be: a. used as a nutrient for the plant b. converted back to RuBP (recycled) GLUCOSE c. converted to GLUCOSE

10 Who first figured out this process? Melvin Calvin CALVIN CYCLE Because of his work, the light independent reaction is known more commonly as the “CALVIN CYCLE” carbon fixation It is also known as “carbon fixation” because carbon is converted to a usable and organic molecule.

11 Melvin Calvin 1911 – 1997 Nobel Laureate

12 Calvin worked with Benson so the cycle is also called the Calvin – Benson cycle

13 What happens during photosynthesis? Carbon dioxide enters the leaf through holes called stomatastomata CO 2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucose The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue (example: cellulose)

14 Why is this important to us? 1. Because we cannot make our own food (glucose, energy), we must get our food from plants. Plants are the first step in the food chain.

15 Why is this important to us? 2. The oxygen released during photosynthesis is necessary for all living things. Why do we need oxygen? For energy... We “burn up” our food. (OXIDATION REACTION)

16 Summary Location:Location: chloroplasts of green plant cells Reactants:Reactants: CO 2 and H 2 O Catalysts:Catalysts: light energy and chloroplasts Main Product:Main Product: glucose By-product:By-product: oxygen Includes:Includes: light reaction and light-independent reaction (Calvin cycle)

17 Chemosynthesis Bacterial process Uses chemicals as energy source instead of light to make food (carbohydrates) Occurs in such places as bottom of the ocean around vents

18 What is Cellular Respiration? Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy into a form that can be used by the organism. photosynthesis This process is cellular respiration.

19 What is Cellular Respiration? The release of chemical energy for use by cells. In what cell part does this occur in eukaryotic cells? The mitochondria

20 Describe Cellular Respiration The breakdown of glucose molecules to release energy Takes place in all living things Is a step by step process

21 What is the chemical equation for cellular respiration?

22 What two processes make up cellular respiration? anaerobic phaseThe anaerobic phase takes place first in the cytoplasm aerobic phaseThe aerobic phase mitochondria follows the anaerobic phase and takes place in the mitochondria

23 The Anaerobic Phase First step occurs in the cytoplasm Glucose breaks down into pyruvate (two 3 carbon sugars) This is called “GLYCOLYSIS” 2 ATPs produced (net gain)

24 The Aerobic Phase Pyruvate enters the mitochondria Includes a series of reactions called the Krebs cycle Another part of this process is the “electron transport chain” - a series of reactions that end with oxygen 34 ATPs produced

25 Summary Location: mitochondriaeukaryoticLocation: mitochondria of all eukaryotic cells Reactants: glucoseoxygenReactants: glucose and oxygen Catalysts: enzymesCatalysts: enzymes Main Product: energy (ATPs)Main Product: energy (ATPs) By-products: CO 2 H 2 OBy-products: CO 2 and H 2 O Includes: anaerobic and aerobic phasesIncludes: anaerobic and aerobic phases

26 Together, what do photosynthesis and respiration form??? THE CARBON CYCLE

27 So what happens in bacteria and yeast?


29 Fermentation Two types: –Alcoholic fermentation: Yeast - 2 ATPs C 6 H 12 O 6 -> CO2 + ethyl alcohol + energy(2ATPs) Lactic Acid fermentation bacteria and muscle cells (without O 2 ) - 2 ATPs C 6 H 12 O 6 -> lactic acid + energy (2 ATPs)

30 Photosynthesis & Respiration THE END

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