Photosynthesis and Respiration

1. Photosynthesis and Respiration Chapter 6

2. Photosynthesis • The process by which plants convert the energy of sunlight into the energy of chemical bonds (sugar and starch) • Plants make organic compounds (Carbs) from inorganic compounds (Water and CO2)

3. The equation • Carbon Dioxide + water  sugar + Oxygen • CO2 + H20  C6H12O6 + O2

4. Sunlight • All organism depend on sunlight for energy • Autotrophs – directly depend on energy to make food • Heterotrophs – indirectly depend on energy because they need to consume autotrophs

5. Pigments • Colored substances that absorb or reflect light • Capture the light energy to be used by the cell • Found in chloroplasts • Chlorophyll – appears green

6. Energy storing compounds • When pigments absorb light they boost electrons to a higher energy level • They either are picked up by an electron carrier NADP+  NADPH • Or they are used to make Adenosine Triphosphate (ATP) from AMP or ADP

7. Complete the following in your purple book • Pg 117 #1-4 and problem solving

8. DNA RNA (protein Synthesis) Mitosis Meiosis Gregor Mendel Karyotypes and Punnett Suqares Human Genome project Selective breeding (transgenic plants and animals) Sex-linked traits Non-disjunction disorders Mutations Hemophilia & Muscular Dystrophy Kleinfelters and Turner syndrome Dwarfism & Downs Syndrome Genetic Engineering Evolution (Darwin) Project topics

9. Photosynthesis – the process • Two parts • 1) light reaction – Captures light energy and converts it to stored energy (NADPH or ATP) • Requires sunlight • 2) Dark reaction – used stored energy to convert CO2 into sugar

10. Light Reaction • Photosynthetic membrane – membrane within the chloroplast • Contains Photosystems –clusters of pigment molecules (both chlorophyll and accessory pigments) • Photosystem I and Photosystem II

11. When photosystems are hit with sunlight electrons are boosted and released • These electrons are picked up by NADP+ and ADP • These storage molecules will be used to fuel the dark reaction

12. Electron transport chain (ETC) • In order to be picked up by electron carriers the molecules must pass down the ETC • Electrons released by Chlorophyll will be replaced by the breakdown of water • Oxygen from the breakdown of water is released as waste

13. Summary of the light reaction • Light hits a photosystem within the chloroplast and boosts the electron level • These electrons are passed down the ETC and picked up by NADP+ and ADP • The electrons are replaced by the breakdown of water • Oxygen is a waste product

14. ???? • What is the formula for photosynthesis? • What are the reactants? • What are the products? • What is the main pigment used in photosynthesis? • What replaces the electrons lost in the light reaction? • What two molecules pick up electrons and take them down the ETC to the dark reaction?

15. The dark reaction • Light does not play a direct part in the reaction • Also known as the Calvin cycle

16. Five steps of the Calvin Cycle • 1st - 3(CO2) combines with a 3(5C) molecules and form 3 (6C) molecules • 2nd – The 6C molecules split and make 6 (3C) molecules • 3rd – The molecules rearrange to make 6 (3C) molecules called PGAL • NADPH and ATP are used

17. 4th – 1 PGAL is released and 5 PGAL move on • 5th – the 5 (3C) PGAL molecules rearrange to form 3 (5C) molecules • The cycle repeats

18. Glycolysis and Respiration • Break down of sugar • Glycolysis – sugar is not completely broken down • Respiration – sugar is completely broken down • C6H12O6 + 6O2 6CO2 + + 6H20

19. 3(CO2) 3(6C) 3(5C) 5 PGAL (3C) 6(3C) 6 PGAL(3C) 1PGAL (3C)

20. Groups • Names • Topic • Textbook pages • 8-10 facts

21. Questions?????? • How does the formula for respiration compare to the formula for photosynthesis? • How do they differ in their use/release of energy? • Write this equation using words. • What are the reactants for respiration? • What are the products for respiration?

22. Glycolysis • Initial breakdown of glucose molecule • 6C sugar is broken down into 2 (3C) PGAL molecules • 2 ATP molecules are needed for this to occur • These two PGAL are then converted to pyruvic acid also a 3C molecule • 4 ATP and 2 NADH are produced • There is a net gain of 2 ATP and 2 NADH

23. Respiration • If Oxygen is available Respiration will occur • In this process the two pyruvic acid produced during glycolysis are further broken down during the Krebs cycle • This process takes place in the inner membrane of the mitochondria

24. Steps of the Krebs cycle • 1st – Pyruvic acid (3C) is converted to acetyl-CoA a 2C molecule; 1 CO2 is released • 2nd – the acetyl CoA enters the Krebs cycle and joins with a 4C molecule to create a citric acid a 6C molecule • 3rd – This 6C molecule is converted to a 5 C molecule by releasing 1 CO2 and NADH

25. 4th - This 5C molecule is converted to a 4C molecule by releasing 1 CO2 and NADH • 5th – This 4C molecule is further transformed creating 1GTP, 1 NADH and 1FADH2 • The cycle begins again

26. Overview of Respiration • 2 Carbon atoms are added in the form of pyruvic acid • 2 Carbon atoms are removed in the from of CO2 • 3 NADH, 1FADH2 and 1 GTP molecules are formed • 2 turns yield 6NADH, 2 FADH2 and 2 GTP

27. ETC • Electrons from electron carriers (NADH, FADH2 and GTP) are passed down an ETC to form ATP • 1 GTP – 1 ATP • 1 NADH – 3 ATP • 1 FADH2 – 2 ATP

28. ATP yield Intermediate reaction • 2 NADH – 6 ATP Krebs Cycle • 2 GTP – 2 ATP • 6 NADH – 18 ATP • 2 FADH2 – 4 ATP

29. Fermentation • If cells do not have Oxygen they can not enter the intermediate step nor the Krebs cycle • They will perform fermentation • Fermentation does not require Oxygen and simply changes pyruvic acid to a more useful

30. Types of fermentation • Lactic acid fermentation • Muscles • Alcoholic fermentation • Yeast • Uses the NADH produced in glycolysis • Yields 2ATP