Cellular Metabolism: Photosynthesis and Cellular Respiration Chapters 8-9

What is the ultimate purpose of nutrition? To obtain energy We use this energy for: to fuel life processes Getting ATP out of glucose is called____________ and it occurs in the ________ of Eukaryotes.

How do organisms get nutrition? Autotrophs or producers obtain glucose by producing it. Photosynthesis converts light energy into food energy. Examples of organisms: Cyanobacteria (blue-green algae), plants, protists, Heterotrophs or consumers obtain food/glucose by consumer other organisms. Examples- Animals

Venus Flytraps – missing some important amino acids so they get it from insects.

The chemical reaction for Photosynthesis is: sunlight Water + Carbon Dioxide + ----------> Glucose + Oxygen 6H2O + 6CO2 ----------> C6H12O6+ 6O2 The chemical reaction for Cellular Respiration is: Glucose + Oxygen ------------ Carbon Dioxide + Water Energy C6H12O6  +  6O2  -------  6CO2  +  6 H2O    36 ATP

ATP-Adenosine TriphosphateATP the most important energy-containing compound in biological systems. The energy from ATP can be used for : mechanical functions ____________________________________________________________ active transport ____________________________________________________________ chemical reactions necessary for life ______________________________ ____________________________________________________________

More than 10 million new ATP molecules are produced per second in cells. Muscle and nerve cells produce even more! An ATP molecule releases energy whenever …… …….last phosphate bond is broken

Cellular Respiration: The Use of Food Energy to make ATP The process by which chemical energy stored in food is used to form ATP to fuel life processes. The balanced equation for cellular respiration: C6H12O6  +  6O2  ------  6CO2  +  6 H2O    36 ATP What types of organisms conduct cellular respiration? ALL living organisms ALL OF THE TIME.

1st – we will discuss photosynthesis (producers only) 2nd – we will discuss cellular respiration (ALL organisms – producers, consumers, decomposers)

Chloroplast Organelle where photosynthesis takes place. Stroma Outer Membrane Thylakoid Granum Inner Membrane Thylakoid stacks are connected together

The two chemical reactions of photosynthesis are localized: Photosynthesis - 2 stages Light Dependent Reactions Light Independent Reactions (used to be called dark reactions) The two chemical reactions of photosynthesis are localized: light-dependent reactions- occurs on the thylakoid membranes of the chloroplast light-independent reactions - occurs in the surrounding stroma

Two Groups of Reactions Light-dependent reactions Chlorophyll and other molecules of the thylakoids trap sunlight energy Sunlight energy is converted to the energy carrier molecules ATP and NADPH Water molecule is split and Oxygen gas is released as a by-product

Two Groups of Reactions Light-independent reactions Enzymes in the stroma synthesize glucose and other organic molecules using the chemical energy stored in ATP and NADPH Inorganic CO2 gets converted to glucose C6H12O6 Organic

Pigments: The color of an object is the color of the light that it _____________________. There are different types of pigments that can be used in photosynthesis: The most important is Chlorophyll -blue/green in color-it absorbs mainly red and blue wavelengths of light Others include: Carotene-orange color Xanthophyll-yellow color These pigments are seen in the fall when the main pigments are moved to the roots of the plant

The Big Picture of Photosynthesis Light “Dependent” Reactions Light sends electrons in the thylakoid to a high energy state Water is split to replace electrons and oxygen is formed Light “Independent” Reactions ATP used to convert 6 carbon dioxide molecules into glucose

Balanced Equation for Photosynthesis sunlight 6H2O + 6CO2 ----------> C6H12O6+ 6O2 How many molecules of CO2 are used to make one glucose molecule? ____ How many molecules of H2O must be split to make one molecule of glucose?____ How many molecules of oxygen (O2) are formed in the equation? _____ Like cellular respiration, photosynthesis is a series of chemical reactions called a series of reactions that together are called a biochemical pathway

WHAT DO PLANTS USE GLUCOSE FOR? 1) Cellular Respiration 2) stored as starch 3) forms cell wall (cellulose)

WHAT DO ANIMALS USE GLUCOSE FOR? 1)_Cellular respiration 2) stored as glycogen 3)energy is used to build other compounds like proteins, lipids and nucleic acids.

Cellular Respiration is also more complex than one simple reaction Cellular Respiration is also more complex than one simple reaction. It occurs in 3 stages. 1. glycolysis 2. kreb cycle 3. electron transport chain …assuming there is oxygen for aerobic cellular respiration.

Cellular respiration is not one single reaction Cellular respiration is not one single reaction. Instead it is a series of reactions that together are called a biochemical pathway. All types of organic compounds including carbohydrates, lipids and proteins can be used at points along the biochemical pathway in order to form ATP.

copyright cmassengale 1. Glycolysis C-C-C-C-C-C C-C-C Glucose (6C) 2 ATP - used 4 ATP - produced NET – 2 ATP produced 2ATP 2ADP + P copyright cmassengale

copyright cmassengale 2. Krebs Cycle (Citric Acid Cycle) (actually an intermediate step before this (3 C  2 C) Krebs Cycle 1 Acetyl CoA (2C) 3 NAD+ 3 NADH FAD FADH2 ATP ADP + P (one turn) OAA (4C) Citrate (6C) 2 CO2 copyright cmassengale

copyright cmassengale 3. ETC - Electron Transport Chain and Oxidative Phosphorylation (Chemiosmosis for NADH) NADH + H+ ATP Synthase 1H+ 2H+ 3H+ higher H+ concentration H+ ADP + lower H+ (Proton Pumping) P E T C NAD+ 2H+ + 1/2O2 H2O Intermembrane Space Matrix Inner Mitochondrial Membrane copyright cmassengale

FIGURE 8-1 A summary of glucose metabolism

Overview of Glucose Breakdown If oxygen is absent fermentation occurs pyruvate is converted into either lactate, or into ethanol and CO2 If oxygen is present cellular respiration occurs

Overview of Glucose Breakdown The main stages of glucose metabolism are: Glycolysis Cellular respiration (if oxygen is present then the products of glycolysis go to the mitochondria and kreb cycle and electron transport chain (ETC) occurs producing a lot of ATP – most of the ATP is made during the ETC ) If no oxygen is present then anaerobic respiration takes place - fementation

Anaereobic Respiration or Fermentation: Production of ATP in the absence of Oxygen

Two Types of Cellular Respiration Respiration using oxygen: Aerobic Cellular Respiration Found in : most plants and animals Respiration without oxygen: Anaerobic cellular respiration Found in : unicellular organisms (bacteria yeast) -possible in plants and animals-human muscles too

Alcohol fermentation glycolysis produces 2 ATPs and fermentation produces alcohol and carbon dioxide Glycolysis is the first step: chemical equation: Heat Heat C6H12O6 ---- 2C3H4O3 ---- Ethanol + CO2 Certain bacteria and yeasts undergo alcohol fermentation when oxygen is in short supply. We use yeast and alcohol fermentation to brew beer.

Alcoholic Fermentation produces alcohol and CO2

Energy difference between the two types of respiration about 34 ATPs! Aerobic Cellular Respiration = 36 ATPs!!! Anaerobic Cellular Respiration =2 ATPs!!! Which is more effictive?_____________

Stages in Aerobic Cellular Respiration: A. Glycolysis: Glycolysis means to split glucose: glyco- (glucose) + –lysis (to split). Glycolysis takes place in the cytoplasm During glycolysis: glucose is split into 2 molecules of pyruvic acid. Pyruvic acid is 3-carbon molecule. The equation for glycolysis: C6H12O6  2C3H4O3

B. Aerobic Cellular Respiration to Form ATP : Aerobic Cellular Respiration takes place in the _mitochondria During Aerobic Cellular Respiration: pyruvic acid molecules are split further to form a total of 34 ATP per glucose molecule.

The Big Picture of Aerobic Cellular Respiration 1) Reactions in Glycolysis occur in the cytoplasm Additional Reactions needed to form ATP: Krebs Cycle – 2 ATPs Electron Transport Chain – 32 ATPs!!! 3) These additional reactions occur in: mitochondria

Efficiency of aerobic cellular respiration: 60% of energy from food is converted into ATP Think back to cellular transport: If a cell has to use active transport to bring a molecule of glucose into the cell for cellular respiration, is it worth it for the amount of energy the cell gets from the molecule of glucose? Yes, 1 ATP molecule used to bring 1 molecule of glucose into the cell 1 molecule of glucose can produce about 36 ATP

Plant that beer is made from

Lactic acid fermentation glycolysis produces 2ATPs and lactic acid Glycolysis is the first step chemical equation: Heat Heat C6H12O6 --- 2C3H4O3 --- Lactic Acid Lactic acid fermentation occurs in bacteria, fungi and even human muscles.

Feel the Burn! No Pain No GAIN!! What causes the “muscle burn” after extreme workouts? Not enough oxygen gets to your muscles as you are working out, so ATP is produced via lactic acid fermentation. The Lactic Acid build up in your muscles causes the burning sensation.