Compare the light absorption of chlorophyll A and chlorophyll B. Bell Ringer (1) Compare the light absorption of chlorophyll A and chlorophyll B. Hint: Use the graph on pg. 207 Then read pg. 209!

Photosynthesis Reactions Unit 4: Energize Your Life

Plants Autotrophs – produce their own food (glucose) Process called photosynthesis Mainly occurs in the leaves: a. stoma - pores b. mesophyll cells Mesophyll Cell Chloroplast Stoma 3

2 Parts of Photosynthesis Light-Dependent Reactions Requires light Occurs in the thylakoids Light-Independent Reactions (a.k.a. Dark Reaction or Calvin Cycle) Does NOT require light Occurs in the stroma

Light-Dependent Big Idea Light is absorbed by chlorophyll to split water molecules and give off oxygen. This “charges up” the energy molecules ATP and NADPH. Photosystem II  ETC (Chemiosmosis) Photosystem I

Noncyclic Electron Flow P700 Photosystem I P680 Photosystem II Primary Electron Acceptor ETC Enzyme Reaction H2O 1/2O2 + 2H+ ATP NADPH Photon 2e- SUN H2O is split in PSII & ATP is made, while the energy carrier NADPH is made in PSI 6

Chemiosmosis ADP + P ATP PS II PS I E T C Thylakoid Space H+ H+ ATP Synthase high H+ concentration H+ ADP + P ATP PS II PS I E T C low H+ Thylakoid Space SUN (Proton Pumping) 7

Light-Independent (Calvin Cycle) Big Idea Energy is used from ATP and NADPH. The “left-over” hydrogens from the water are carried to the stroma by NADPH. They are combined with CO2 to make glucose. (Carbon Fixation)

Calvin Cycle (C3 fixation) 6CO2 6C-C-C-C-C-C 6C-C-C 6C-C-C-C-C 12PGA RuBP 12G3P (unstable) 6NADPH 6ATP C-C-C-C-C-C Glucose (6C) (36C) (30C) C3 glucose 9

Light-Dependent Light-Independent Reaction Reaction (Calvin Cycle) Energy Source = ATP and NADPH Occurs in the Stroma Changes ATP into ADP Changes NADPH into NADP Uses CO2 & “left-over” H from NADPH Produces Glucose Energy Source= Light Occurs in the Thylakoids Changes ADP into ATP Changes NADP into NADPH Uses H2O Produces Oxygen Gas

Energy for Life on Earth Sunlight is the ULTIMATE energy for all life on Earth Plants store energy in the chemical bonds of sugars Chemical energy is released as ATP during cellular respiration 11

How Do We Get Energy From ATP? By breaking the high- energy bonds between the last two phosphates in ATP Copyright Cmassengale 12

What is the Process Called? HYDROLYSIS (Adding H2O) H2O Copyright Cmassengale 13

Copyright Cmassengale How is ATP Re-Made? The reverse of the previous process occurs. Another Enzyme is used! ATP Synthase Copyright Cmassengale 14

Overall Equation for Cellular Respiration C6H12O6 + 6O2 YIELDS 6CO2 + 6H20 + e- + 36-38ATP’s Copyright Cmassengale 15

Other Cellular Respiration Facts Metabolic Pathway that breaks down carbohydrates Process is Exergonic as High-energy Glucose is broken into CO2 and H2O Process is also Catabolic because larger Glucose breaks into smaller molecules Copyright Cmassengale 16

Where Does Cellular Respiration Take Place? It actually takes place in two parts of the cell: Glycolysis occurs in the Cytoplasm Krebs Cycle & ETC Take place in the Mitochondria Copyright Cmassengale 17

Copyright Cmassengale Glycolysis Summary Takes place in the Cytoplasm Anaerobic (Doesn’t Use Oxygen) Requires input of 2 ATP Glucose split into two molecules of Pyruvate or Pyruvic Acid Also produces 2 NADH and 4 ATP Pyruvate is oxidized to Acetyl CoA and CO2 is removed Copyright Cmassengale 18

Copyright Cmassengale Fermentation Occurs when O2 NOT present (anaerobic) Called Lactic Acid fermentation in muscle cells (makes muscles tired) Produces Lactic Acid and NAD+ Called Alcoholic fermentation in yeast Produces Ethyl Alcohol, CO2, and NAD+ 0 additional ATP are produced after Glycolysis Copyright Cmassengale 19

Copyright Cmassengale Krebs Cycle ATP NETS: 3NADH, 1ATP, 1FADH2, & 2CO2 Copyright Cmassengale 20

Electron Transport Chain Summary 34 ATP Produced H2O Produced Occurs Across Inner Mitochondrial membrane Uses coenzymes NAD+ and FAD+ to accept e- from glucose NADH = 3 ATP’s FADH2 = 2 ATP’s Copyright Cmassengale 21

Electron Transport Chain Animation Copyright Cmassengale 22