1. 1 Chapter 9 Photosynthesis and Cellular Respiration

2. 2 All living things must be able to produce ENERGY from the environment. All living things must be able to produce ENERGY from the environment. Energy is used to make new molecules, enzymes, maintain homeostasis, carry out active transport, cell division etc… Energy is used to make new molecules, enzymes, maintain homeostasis, carry out active transport, cell division etc…

3. 3 PHOTOSYNTHESIS Two Phases Light dependent – called (light reaction) Light dependent – called (light reaction) Energy from sun is converted into chemical energy Energy from sun is converted into chemical energy Light independent – called (dark reaction) Light independent – called (dark reaction) Uses energy produced from the light dependent to produce glucose Uses energy produced from the light dependent to produce glucose

4. 4 Photosynthesis Autotrophs use energy from sunlight to build Carbohydrates Needs 1. Carbon Dioxide 1. Carbon Dioxide 2. Water 2. Water 3. Chlorophyll 3. Chlorophyll 4. Sunlight 4. Sunlight CO 2 + H 2 O

5. 5 Photosynthesis Produces 1. Glucose 1. Glucose (sugar/monosaccharide) (carbohydrate) (sugar/monosaccharide) (carbohydrate) 2. Oxygen 2. Oxygen 3. Energy (ATP) 3. Energy (ATP) ************ yields C 6 H 12 O 6 + O 2 + ATP

6. 6 Photosynthesis Chemical equation 6CO 2 + 6H 2 O yields C 6 H 12 O 6 + 6O 2 + ATP 6CO 2 + 6H 2 O yields C 6 H 12 O 6 + 6O 2 + ATP Carbon Dioxide + Water yields Glucose + Oxygen + Energy (Needs/Uses) (Produces) (Needs/Uses) (Produces) Reactants Products Reactants Products

7. 7 Light – Dependent Reaction – Thylakoid Membranes First phase (requires sunlight) First phase (requires sunlight) Sunlight strikes chlorophyll molecules in THYLAKOID membranes of a chloroplast Sunlight strikes chlorophyll molecules in THYLAKOID membranes of a chloroplast Chlorophyll traps the energy Chlorophyll traps the energy Light is transferred to electrons and this begins the electron transport chain. Light is transferred to electrons and this begins the electron transport chain. Electron transport chain – passing of electrons along a series of molecules, releasing energy as they go Electron transport chain – passing of electrons along a series of molecules, releasing energy as they go Photolysis occurs – splitting water Photolysis occurs – splitting water Oxygen is released Oxygen is released Making of NADPH and ATP Making of NADPH and ATP

8. 8 Energy ATP & ADP both contain three common components ATP & ADP both contain three common components 1. Sugar – RIBOSE 2. Nitrogen base – Adenine 3. Phosphates ATP (group of three phosphates) ATP (group of three phosphates) ADP (group of two phosphate) ADP (group of two phosphate) AMP ( one phosphate) AMP ( one phosphate)

9. 9 Energy becomes available when ATP is broken down. Energy becomes available when ATP is broken down. When the bond is broken between two phosphate groups – energy is released When the bond is broken between two phosphate groups – energy is released Cells store energy when a third phosphate group is bonded to a ADP molecule. Cells store energy when a third phosphate group is bonded to a ADP molecule. Need to be able to store energy b/c a cell can not always immediately use all the energy it gets. Need to be able to store energy b/c a cell can not always immediately use all the energy it gets.

10. 10 Light Dependent – Phase 1 1. Light striking chlorophyll molecules in thylakoid membranes is transferred to electrons. 2. Electrons are passed to an electron transport chain. This allows small amounts of the electron's energy to be released at a time. This energy is used to both form ATP and pump hydrogen ions.

11. 11 Light Independent - Phase 2 (CALVIN CYCLE) Synthesizing of Glucose Synthesizing of Glucose 1. Second phase – does NOT require light 2. Carbon fixation cycle of photosynthesis 3. Occurs in the STROMA of the chloroplast Energy for this phase is supplied from the first phases making of ATP

12. 12 Light Independent CALVIN CYCLE Carbon Fixation Carbon Fixation One carbon atom from carbon dioxide is added to a five-carbon sugar. (RIBOSE) One carbon atom from carbon dioxide is added to a five-carbon sugar. (RIBOSE) PGA is formed PGA is formed NADPH and ATP is used to split PGA NADPH and ATP is used to split PGA Glucose is produced Glucose is produced Some PGA molecules reform ribose Some PGA molecules reform ribose

13. 13 Energy in Glucose can be released by three processes Energy in Glucose can be released by three processes 1. Respiration 2. Glycolysis 3. Burning

14. 14 CELLULAR RESPIRATION Breaking down of Glucose Three stages 1. Glycolysis – Anaerobic (produce 2 ATP)- Cytoplasm 2. Citric acid cycle – Aerobic (produce 2 ATP)- Mitochondria 3. Electron transport chain – Aerobic (produce 32 ATP)- Mitochondria Cellular respiration (aerobic process) is MORE efficient than (fermentation -glycolysis) Cellular respiration (aerobic process) is MORE efficient than (fermentation -glycolysis)

15. 15 Cellular Respiration Glycolysis Series of chemical reactions in the cytoplasm of the cell. (anaerobic) no mitochondria Series of chemical reactions in the cytoplasm of the cell. (anaerobic) no mitochondria Breaks down glucose ( six-carbon carbohydrate sugar, into two molecules of pyruvic acid Breaks down glucose ( six-carbon carbohydrate sugar, into two molecules of pyruvic acid Not very efficient – Produces 4 ATPs but uses 2 ATPs for a net gain of only 2 ATPs Not very efficient – Produces 4 ATPs but uses 2 ATPs for a net gain of only 2 ATPs

16. 16 Glycolysis Anaerobic process of splitting glucose to form pyruvic acid Anaerobic process of splitting glucose to form pyruvic acid Two molecules of ATP are used in the first step, and Four molecules of ATP are produced in the second step Two molecules of ATP are used in the first step, and Four molecules of ATP are produced in the second step Occurs in cytoplasm (anaerobic) Occurs in cytoplasm (anaerobic)

17. 17 Cellular Respiration Citric Acid Cycle Citric Acid Cycle is Aerobic (uses oxygen) Citric Acid Cycle is Aerobic (uses oxygen) Occurs in the MITOCHONDRIA Occurs in the MITOCHONDRIA Aerobic repiration series that begins and ends with the same 6-carbon cpd. Aerobic repiration series that begins and ends with the same 6-carbon cpd. Similar to the Calvin cycle in that one of the molecules needed for the first reaction is also one of the end products. Similar to the Calvin cycle in that one of the molecules needed for the first reaction is also one of the end products. One molecule of ATP is produced for every turn of the cycle One molecule of ATP is produced for every turn of the cycle Two electron carriers are used (NAD) and (FAD) Two electron carriers are used (NAD) and (FAD)

18. 18 Cellular Respiration Electron Transport Chain Aerobic – occurs in Mitochondria Aerobic – occurs in Mitochondria NAD and FAD accept Hydrogen and become NADH and FADH NAD and FAD accept Hydrogen and become NADH and FADH NADH and FADH pass energized electrons from protein to protein within the inner membrane (cristea) of the mitochondria NADH and FADH pass energized electrons from protein to protein within the inner membrane (cristea) of the mitochondria This allows for the slow release of energy This allows for the slow release of energy Forming more ATP and pumping hydrogen ions Forming more ATP and pumping hydrogen ions

19. 19 Cellular Respiration This causes a concentration difference and an electrical charge difference within the mitochondria This causes a concentration difference and an electrical charge difference within the mitochondria The final acceptor in the chain is OXYGEN The final acceptor in the chain is OXYGEN Without this oxygen the proteins in the electron transport chain could not pass along the electrons and the aerobic process of cellular respiration would not occur. Without this oxygen the proteins in the electron transport chain could not pass along the electrons and the aerobic process of cellular respiration would not occur. Produces 32 ATP molecules Produces 32 ATP molecules

20. 20 FERMENTATION Two Major Types 1. Alcoholic Fermentation use yeast cells to produce alcohol and carbon dioxide use yeast cells to produce alcohol and carbon dioxide 2. Lactic Acid Fermentation Supplies energy when oxygen is scarce. Pyruvic acid forms lactic acid Supplies energy when oxygen is scarce. Pyruvic acid forms lactic acid

21. 21 Fermentation ATP is produced from Glycolysis without Oxygen ATP is produced from Glycolysis without Oxygen Some forms of Bacteria -produce methane gas Some forms of Bacteria -produce methane gas