1. Chapter 5 Photosynthesis and Cellular Respiration

2. Energy & Living Things Directly or Indirectly almost all of the energy comes from the SUN Metabolism Using energy to build molecules Breaking down molecules where energy is stored

3. Building Molecules That Store Energy Photosynthesis – is the process by which light energy is converted to chemical energy Autotrophs – organisms that use the sun to convert inorganic substances into organic substances

4. Breaking Down Food For Energy Heterotrophs – must eat food to get energy Cellular Respiration – process by which cells produce energy from carbohydrates O2 + C6H12O6  H2O + CO2 Releases energy to make ATP

5. Transfer of Energy to ATP Energy is released in a series of enzyme assisted chemical reactions Food Breaks down into 1) Heat Energy 2) Portable Energy (ATP) ATP drives most cellular activity

6. Adenosine Triphosphate 3 Phosphate Groups 5 Carbon Sugar (Ribose) Phosphate Tail is negatively charged Energy is released when phosphate bonds are broken H2O + ATP  ADP + P + energy Energy released powers metabolism

7. Section 1 Review 1. What is the primary source of energy that flows through most living systems? 2. Organisms that can make their own food using energy from the sun are called ___________. 3. How is energy released from ATP?

8. Photosynthesis Stage 1: Energy is captured from sunlight Stage 2: Light energy is converted to chemical energy, which is temporarily stored in ATP and the energy carrier molecule NADPH Stage 3: ATP & NADPH powers the formation of organic compounds using CO2

9. Photosynthesis 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Important for life processes Sugars form starch Starch is broken down to produce ATP Sugar fragments form Proteins, Nucleic Acids & other molecules

10. Stage 1: Absorption of Light Energy “Light Dependent Stage” Require Sun Light Pigments – light absorbing substances Carotenoids & Chlorophyll –a and b Pigments in plants Enables plants to absorb more light Located in the Thylakoids of a chloroplast

11. Production of Oxygen Electrons get “excited” Electrons leave the chlorophyll Replaced by e- from split H2O molecules H electron replaces excited electron Leaving H+ ions & O2 (oxygen gas) Electrons are used to power the 2 nd stage of Photosynthesis

12. Stage 2: Conversion of Light Energy Excited e- are used to make ATP Electron Transport Chains 1 st  Located b/t 2 chlorophyll pigments Contains a protein that acts as a membrane pump Excited e- pass through the protein Electrons lose energy Energy is used to pump H+ into the thylakoid

13. 1 st Electron Transport Chain H+ ions are also produced when H2O molecules split H+ are highly concentrated inside H+ diffuse out of the thylakoid – down the concentration gradient through carrier proteins Carrier Proteins – act as an Ion Channel & Enzyme

14. 1 st Electron Transport Chain 1. H+ pass through the channel 2. The protein catalyzes a reaction 3. A Phosphate group is added to ADP 4. ATP is made 5. ATP is used to power Stage 3

15. 2 nd Electron Transport Chain Provides energy to make NADPH NADPH – is an electron carrier that provides the high energy e- needed to make C-H bonds in stage 3 NADP – is and electron acceptor E- + H ions + NADP+  NADPH

16. Light Dependent Stages Summary (Stages 1 & 2) 1) Pigment molecules in the thylakoid absorb light 2) E- are excited by light & move through 2 Electron Transport Chains 3) Excited e- leaving the thylakoid are replaced by e- from H20 that is split by an enzyme 4) O atoms combine and form O2 5) H+ accumulate inside the thylakoid setting up a concentration gradient that provides the energy to make ATP

17. Stage 3: Storage of Energy Light Independent Stage Carbon atoms are used to make organic compounds to store chemical energy CARBON DIOXIDE FIXATION The Calvin Cycle A series of enzyme-assisted chemical reactions that produce a 3-C sugar

18. Calvin Cycle Melvin Calvin Step 1: Enzymes add CO2 to a 5-C compound Step 2: The 6-C compound splits into two 3-C compounds P groups form ATP Electrons form NADPH Both are added forming 3-C sugars

19. Calvin Cycle Step 3: One 3-C sugar is used to make organic compounds Step 4: Other 3-C sugars are used to regenerate the initial 5-C compound The organic compounds provide the organism with energy for growth & metabolism

20. Factors that Affect Photosynthesis #1 – Light #2 – Carbon Dioxide #3 – Temperature

21. Section 2 Review 1. T/F Chloroplasts are found within the thylakoid membrane. 2. T/F Carbon Dioxide fixation takes place during the Calvin Cycle. 3. The electron transport chain converts light energy to chemical energy during the __ stage of photosynthesis. 4. During photosynthesis, plants store energy in this…

22. Section 3: Cellular Respiration Energy is stored in proteins, carbohydrates and fats Cells transfer the energy in organic compound to ATP through CELLULAR RESPIRATION Metabolism  describes the sum of all chemical reactions Aerobic = Requires Oxygen Anaerobic = Does NOT require Oxygen

23. Cellular Respiration C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + ENERGY Takes place in the Mitochondria Stage 1: Glucose is converted to Pyruvate, producing small amounts of ATP and NADH Stage 2: Aerobic Respiration – Pyruvate & NADH make large amounts of ATP Anaerobic Respiration – Pyruvate is converted into Lactic Acid or Ethanol & CO2

24. Stage 1: Breakdown of Glucose Fuel – Glucose Glucose is broken down in the cytoplasm during GLYCOLYSIS Glycolysis – is an enzyme assisted anaerobic process that breaks down one 6-C molecules into two 3-C pyruvate ions

25. Stage 1: Breakdown of Glucose Pyruvate – is the ion of a 3-C organic acid called pyruvic acid Broken down glucose transfers H+ ions to NAD+ forming NADH NAD + is an electron acceptor NADH is an electron carrier NADH donates electrons to organic compounds turning back into NAD

26. Summary of Stage 1 1. Phosphate groups from 2 ATP molecules are transferred to glucose (3 reactions) 2. 6-C compound is broken into two 3-C compounds, each with a Phosphate group (2 reactions) 3. 2 NADH molecules are produced, 1 phosphate group is transferred to a 3-C compound 4. Each 3-C compound is converted into a 3-C pyruvate, producing 4 ATP molecules

27. Stage 1 to Stage 2 Glycolyisis uses 2 ATP molecules to make 4 ATP molecules – 2 net ATPs Pyruvate produced in glycolysis enters the mitochondria and is converted into a 2-C compound 1 – CO2 1 – NADH 1 – acetyl-CoA

28. Stage 2: Production of ATP Acetyl-CoA enters a series of enzyme assisted reactions called the KREBS CYCLE Step 1: Acetyl-CoA combines with a 4-C compound forming a 6-C compound & releasing Coenzyme A Step 2: CO2 is released from the 6-C compound forming a 5-C compound Electrons + NAD  NADH

29. Stage 2: Production of ATP Step 3: CO2 is released from the 5-C compound resulting in a 4-C compound ATP & NADH is made Step 4: 4-C compound is converted to a new 4-C compound Electrons are transferred from FAD to FADH2 Step 5: The new 4-C compound is converted to the 4-C compound that began the cycle Another NADH molecule is produced

30. After the Krebs Cycle NADH & FADH2 contain much of the energy previously stored in glucose & pyruvate Donated electrons from NADH & FADH2 enter the Electron Transport Chain in the mitochondria membrane Electrons are used to help move H+ ions ATP & O2 is produced

31. Anaerobic Respiration Electron Chain does NOT function NAD+ has to be recycled in another way Recycling NAD+ using an organic H acceptor is called FERMENTATION 1. Lactic Acid – exhausted muscles, yogurt & cheese 2. Alcoholic Fermentation – releases CO2 – making bread, beer & wine

32. Production of ATP After Glycolysis 1 of 2 paths: 1. Oxygen Present  Krebs Cycle 2. Oxygen Absent  Fermentation ATP Produced Fermentation – None Krebs Cycle – 2 Electron Transport Chain  34 ATP