Photosynthesis & Cellular Respiration Ch. 8 & 9

Autotrophs - Photosynthesis Heterotrophs – Eat food Food and Energy

-Autotrophs: organisms that make their own food Ex. Plants, algae, some bacteria -Heterotrophs: feed on other organisms Ex. Animals, fungi, some bacteria, some protists Organisms & their Sources of Energy

Chapter Overview: Food & Energy Plants Food Animals ATP Photosynthesis (chloroplast) Cell Respiration (mitochondria) Consume food (digestive sys)

ATP Energy Molecule – ATP – adenosine triphosphate Cells store energy by adding a phosphate group to ADP Cells release energy from ATP by subtracting a phosphate group ATP= high energy molecule; ADP= low energy molecule High energy bond

Green plants trap energy from sunlight in their leaves and make food (glucose) We get our energy from the food (glucose) plants made during photosynthesis when we eat plants or eat animals that ate the plants by cellular respiration. O2O2 CO 2 ATP!! The Big Picture!

ProcessPhotosynthesisCell Respiration Who?AutotrophsAuto & Heterotrophs Where?ChloroplastMitochondria Source of energySun = light energyGlucose (food/chem energy) Produces/makes?Glucose (food/chem energy) ATP (energy) Photosynthesis and Cell Respiration Overview

Ch. 8-1 Energy and Life

Ch. 8-2: PHOTOSYNTHESIS

Photosynthesis Equation 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 reactantsproducts

Photosynthesis occurs in the Chloroplast Parts of the Chloroplast: - thylakoid: flattened sacs that contain pigments (chlorophyll) -stroma: protein rich fluid surrounding thylakoid -grana: stack of thylakoids

Photosynthesis Pigments absorb light and convert it to chemical energy (glucose) Types of pigments: Chlorophyll a (dark green); chlorophyll b (light green); carotenoids (yellow/orange/red)

Pigment - Chlorophyll Responsible for absorbing and reflecting sunlight

Why do leaves change color in the fall? Leaves contain many light absorbing/reflecting pigments During autumn, when less light is available, chlorophyll does not reflect as much, allowing other pigments, which reflect different colors to show through

Photosynthesis Overview 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 LIGHT ENERGY Carbon Dioxide WaterGlucose Oxygen Light Energy Chloroplast CO 2 + H 2 O Sugars + O 2

Photosynthesis -“The Reaction” 6CO 2 + 6H 2 O --> C 6 H 12 O O 2 2 Stages of Photosynthesis 1. Light Dependent Rxn 2. Light Independent Rxn (Calvin cycle)

Light Dependent Reactions 1.light energy absorbed (by thylakoids) 2.H 2 O split, breaking into three pieces H 2 O--> O 2 + H + + e - 3. O 2 exits the leaves (becomes our breathing O 2 ) 4. H+ and e- carried onto step 2 by NADP+ and ADP

Side Note: High Energy Electron Light energy produces high energy electrons in chlorophyll, which are used in photosynthesis. Electron Carrier: accept high-energy electrons and transfer them to another molecule. -2 Types: *FAD is used in cell respiration – we’ll talk about this later! Name Without e - # of e - picked upName With e - NADP + 2e - NADPH FAD + 2e - FADH

Light Dependent Reactions H2OH2O Sun (light energy) O2O2 LDR thylakoid ATP ADP & P NADP+ NADPH e - H +

Light Independent (Calvin Cycle) - Takes place in the stroma 1. CO 2 enters thru stomata 2. H + (from light dependent rxn) is combined with CO 2 to produce Glucose = C 6 H 12 O 6 - ATP is a little burst of energy to make the Calvin cycle start *Can take place in light or dark

H 2 O and O 2 leave through Stomata Stomata CO 2 enters leaf through Stomata

CO 2 Glucose!! C 6 H 12 O 6 Calvin Cycle stroma ATP ADP & P NADP+ NADPH e - H +

Glucose C 6 H 12 O 6 Where does each atom come from? –6 C comes from CO 2 –12 H comes from H 2 O –6 O comes from CO 2

CO2CO2 C 6 H 12 O 6 Glucose!! Calvin Cycle (stroma) ATP ADP & P NADP+ NADPH H2OH2O Sun (light energy) O2O2 LDR (granum) e - H + Follow the colored atoms!

Factors affecting Photosynthesis 1.Temperature Optimal temps 0 – 35 ° C Remember, enzymes work at specific temps! 2.Light Too much light will not have an extra effect on photosynthesis 3.Water Waxy cuticle prevents water loss

Extreme Photosynthesis C4 Plants –Corn and sugar cane –Hot temps & intense light –Normal amounts of water –Efficient CO2 is obtained even when stomata are closed CAM Plants –Hot temps & intense light –Dry (less water) –Cactus –Open stomata at night only!

Ch.9 Cell Respiration

Cellular Respiration -Glucose is broken down to produce ATP (energy) -Done by ALL living things (plants and animals) Location: occurs in mitochondria Equation: C 6 H 12 O O 2  6CO 2 + 6H 2 O + ATP (the reverse of photosynthesis)

2 Types of Cellular Respiration 1. Aerobic Respiration: O 2 required -produces net total of 38 ATP per glucose 2. Anaerobic Respiration: occurs when there is no O 2 -produces 2 ATP per glucose

1. Glycolysis 2. Citric Acid Cycle (Krebs) 3. Electron Transport Chain 2. Alcoholic Fermentation 2. Lactic Acid Fermentation O 2 present No O 2 present OR 2 POSSIBLE PATHWAYS Aerobic = O 2 Anaerobic = No O 2

3 Stages of Aerobic Cell Resp 1.Glycolysis Breaks glucose Releases 2 ATP 2.Citric Acid Cycle (Krebs Cycle) Releases 2 ATP 3.Electron Transport Chain Releases 34 ATP

1. Glycolysis Glucose Glycolysis Cytoplasm Pyruvic acid Electrons carried in NADH 2

2. Citric Acid Cycle / Krebs Cycle Glucose Glycolysis Cytoplasm Pyruvic acid Electrons carried in NADH Krebs Cycle (matrix) Electrons carried in NADH and FADH 2 Mitochondrion 22

3. Electron Transport Chain Glucose Glycolysis (Cytoplasm) Pyruvic acid Electrons carried in NADH Krebs Cycle (matrix) Electrons carried in NADH and FADH 2 Electron Transport Chain (cristae) Mitochondrion 2234

Anaerobic Cell Respiration If no oxygen is present… Fermentation aka Anaerobic Cell Resp occurs 2 types: –Alcoholic Fermentation –Lactic Acid Fermentation ONLY 2 ATP MADE TOTAL! ** Not efficient! **

Alcohol Fermentation -done by bacteria and yeast, NOT animals 1.Glycolysis 2.Product changed into ethanol (alcohol) + CO 2 Example: Yeast in bread; alcohol in wine/beer

Lactic Acid Fermentation -done by animal cells (humans) 1. Glycolysis 2. Product changed into lactic acid + CO 2 Example: Muscle cramps/fatigue & bacteria in cheese/yogurt

Summary of Cell Respiration

Relationship between plants and animals Without plants, animals could not survive and vice versa! Biochemical Pathway – a set of reactions in which the products of one reaction is used as a reactant in the next reaction. Glucose + O2