Pathway of Energy Energy Flow Chart

1. Pathway of Energy • Energy Flow Chart

2. Photosynthesis – sunlight is captured using chlorophyll and is converted into chemical energy stored in bonds of carbohydrates. • Information • Equation: 6CO2 + 6H2O chlorophyll + sunlight> C6H12O6 + 6O2 Carbon water glucose oxygen dioxide REACTANTS PRODUCTS • Chlorophyll is a green pigment found in the chloroplast. • Autotroph – organism that uses sunlight to make their own food.

3. Where does it occur? • Occurs in the chloroplast • Chloroplasts consists of stacks of membrane sacs called thylakoids. • Stacks of thylakoids are called grana. • A fluid substance surrounds the grana is called stroma. • Chlorophyll is in the thylakoid membrane.

4. Figure 8-6

5. Two main Steps • Light Dependent Reactions: • Set of reactions that convert light energy to chemical energy. • Occurs in the grana of thylakoid. • 2 stages: Stage 1: • Sunlight is converted to electrical energy -> electron transport. • Sunlight is captured by chlorophyll causing water molecules to split.

6. Light Dependent Reaction Stage 1

7. Stage 2: • Electrons pass through the thylakoid membrane through a process called electron transport chain. • ATP (energy) is formed by this process.

8. Light Independent Reactions: • Set of reactions that produce organic compounds, using the chemical energy produced during the light dependent reactions. • Occurs in the stroma (outside the thylakoids). • Sometimes called ‘Dark Reactions.’ • Uses the Calvin Cycle. Calvin Cycle: • Series of reactions where Carbon from CO2 is ‘fixed’ to form a 6-carbon molecule (carbon fixation)  makes glucose.

10. C3 plant – plants that uses the Calvin Cycle where two 3-carbon molecules are joined together to form a 6-carbon (glucose). • CAM – Crassulacean Acid Metabolism; desert plants take in CO2 at night and store as acid till sunlight was present. • Advantage – prevents water moisture loss.

12. Respiration – process by which living organisms obtain energy from the bonds of food molecules. • Information • Equation: C6H12O6 + 6O2 6CO2 + 6H2O + ATP glucose oxygen Carbon water energy dioxide • Autotrophs + heterotrophs (cannot make their own food). • Glucose (food) comes from photosynthesis.

13. 2 Types of Respiration: • Aerobic Respiration – respiration where oxygen is abundantly present. • Produces large amounts of Adenosine triphospate (ATP). • Anaerobic Respiration – respiration where oxygen is NOT abundantly present. • Produces small amounts of ATP. • Also called fermentation. • The Cellular Respiration Process • Glucose enters the body as food  digested  taken into the cells by the bloodstream.

14. Glycolysis – process by which glucose (6-carbon sugar) is broken down into 2 pyruvic acid molecules (3-carbon) • Occurs in the cytoplasm of the cell. • Produces 2 ATP from the breaking of the bonds in glucose. • Figure 9-2, page 222

16. Krebs Cycle:

18. Summary: ProcessAerobicAnaerobic Glycolysis 2 ATP 2 ATP Krebs Cycle 2 ATP 0 ATP E- Trans. chain 32 ATP 0 ATP TOTAL 36 ATP 2 ATP • Aerobic respiration is more efficient, because it produces more energy.

19. Adenosine triphosphate, ATP • Composed of Adenine, ribose, 3 phosphate groups. • Figure 8-2, p. 202 • ADP vs. ATP • ADP = adenosine diphosphate (2) • ATP = adenosine triphosphate (3)

20. Anaerobic Respiration • Lactic Acid Fermentation: • Occurs in animal cells (muscle cells). • Alcoholic Fermentation: • Occurs in plant cells and yeast. • Beer + wine is made this way.

21. Photosynthesis vs. Cell Respiration

22. Oxygen, Carbon, and Nitrogen Cycles • Oxygen + Carbon Cycles

23. Nitrogen cycle • N makes up to 78% of the atmosphere. • Nitrogen fixation – N2 gas is ocnverted to ammonium compounds (NH4OH). • Ammonification – bacteria breakdown waste and decaying organisms to form ammonium compounds (NH4OH). • Nitrification – bacteria form nitrites (NO2) and nitrates (NO3). • Denitrification – bacteria breakdown nitrites and nitrates to form N2 gas.