CHAPTER 9 CELLULAR RESPIRATION

CHAPTER 9: CELLULAR RESPIRATION 9-1 Chermical Pathways A. Chemical Energy and Food Food serves as a source for _________. 1g of glucose (C6H12O6) releases _______ calories. calorie= We gradually release the energy of glucose and other compounds (fats, proteins, and carbohydrates). The process begins with a pathway called__________. If oxygen is present, If oxygen is not present, energy 3,811 the amount of energy needed to raise the temperature of 1g of water 1°C. glycolysis. glycolysis leads to cellular respiration (Krebs cycle and electron transport chain). (process = aerobic) glycolysis leads to fermentation. (process = anaerobic)

Fermentation (without oxygen) Section 9-1 Chemical Pathways Glucose Glycolysis Krebs cycle Electron transport Alcohol or 2. Lactic acid Fermentation (without oxygen)

B. Overview of Cellular Respiration Remember: the ____________ is the organelle known as the “powerhouse”- the site where energy is produced. Cellular respiration takes place in the mitochondria. The equation for cellular respiration= the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen. mitochondria 6O2 + C6H12O6 6CO2 + 6H20 + Energy

________ stores large amounts of energy. The cell can’t release all the energy at one time. It is too much for the cell to handle. 3 main stages of cellular respiration: 1. 2. 3. Glucose Glycolysis (glycol= sugar; lysis=break apart) Krebs Cycle Electron Transport Chain (ETC)

Electron Transport Chain Flowchart Section 9-2 Cellular Respiration Glucose (C6H1206) + Oxygen (02) Glycolysis Krebs Cycle Electron Transport Chain Carbon Dioxide (CO2) + Water (H2O)

Respiration: An Overview Section 9-1 Mitochondrion Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Glucose Electron Transport Chain Krebs Cycle Glycolysis Mitochondrion Cytoplasm 2 2 34 http://scholar.hw.ac.uk/site/biology/activity3.asp

To the electron transport chain C. Glycolysis= the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound. This pathway does not require oxygen Prokaryotes depend on this process alone for ATP. Section 9-1 Glucose 2 Pyruvic acid PGAL (Phosphoglyceraldehyde) To the electron transport chain

1. ATP Production Use__ ATP Makes __ ATP Net gain is __ ATP NADH Production NAD+ (nicotinamide adenine dinucleotide) is an _____________. NAD+ accepts electrons to make ______ (an electron carrier). In glycolysis, ________ are produced. NADH will carry its’ electrons to 2 4 2 Electron carrier NADH 2 NADH the electron transport chain.

3. Overall, Glycolysis produces 2 ATP “Net” (energy molecules) 2 NADH (electron carriers) 2 Pyruvic Acid (3-C sugars) http://youtu.be/EfGlznwfu9U

9-1 [continued...] Fermentation What happens when oxygen is not present? Fermentation= The pyruvic acid can go through one of two types of fermentation: 1. __________ Fermentation Occurs in Pyruvic acid + NADH → Important to ____ released causes bread to rise Anaerobic process release of energy from food molecules by producing ATP in the absence of oxygen. Glycolysis still occurs in the cytoplasm producing pyruvic acid. Alcoholic yeast cells and other microorganisms. alcohol + CO2 + NAD+ bakers and brewers. CO2 11

2. ___________ Fermention Lactic Acid Section 9-1 Glucose Pyruvic acid Lactic acid Produced in our Build up of _________ causes the ______ is Prokaryotes are used to make food because they do produce lactic acid. Some examples: -cheese -kimchi -sour cream -yogurt -sauerkraut -buttermilk -pickles muscle cells when oxygen levels are too low Lactic Acid burning feeling. NAD+ regenerated to keep running glycolysis. 12

Fermentation (without oxygen) Section 9-1 Chemical Pathways Glucose Krebs cycle Electron transport Glycolysis Alcohol or lactic acid Fermentation (without oxygen) http://www.qcc.cuny.edu/BiologicalSciences/Faculty/DMeyer/respiration.html 13

COMPARISON OF FERMENTATION TO CELLULAR REPIRATION Lactic Acid Alcoholic Cellular respiration glucose glucose glucose glycolysis (pyruvic acid) glycolysis (pyruvic acid) glycolysis (pyruvic acid) carbon dioxide carbon dioxide lactic acid alcohol water 2 ATP 2 ATP 38 ATP (net 34) 14

9-2 The Krebs Cycle and Electron Transport A. The Krebs Cycle (aka: Citric Acid Cycle) 1. Pyruvate (pyruvic acid) oxidation 2. Energy Extraction

Named after __________. Occurs in the Mitochondria (therefore this process only occurs in __________) Krebs cycle= Krebs cycle begins Hans Krebs Eukaryotes process where pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. when pyruvic acid enters mitochondria.

1. Pyruvate (pyruvic acid) Oxidation In this process, it produces the following for glucose: - 2 acetyl-CoA (2-C sugar) 2 NADH (electron carriers) 2 Carbon dioxide (waste product)

2. Energy Extraction

Acetyl CoA ( ) binds with a Oxaloacetic acid ( ) molecule to form Citric Acid ( )...Hence, the name Citric Acid Cycle. Citric Acid is oxidized (by NAD+ and FAD) through a series of reactions that finally produces Oxaloacetic Acid again. The Krebs Cycle runs __ times per Glucose molecule. (Once per pyruvic acid.) This process produces (per glucose molecule): - ___ NADH (electron carriers-go to ETC) - ___ FADH2 (electron carriers-go to ETC) - ___ ATP (energy-used by cell to do work) - ___ CO2 (waste product- gets exhaled) 2-C 4-C 6-C 2 6 2 2 4

B. Electron Transport (ETC) The Electron Transport Chain= process that uses the high-energy electrons from the Krebs cycle to convert ADP into ATP. Section 9-2 Electron Transport Hydrogen Ion Movement Channel Mitochondrion Intermembrane Space ATP synthase Inner Membrane Matrix ATP Production

The Process: Electron Transport 1. Glycolysis and the Krebs Cycle deliver their ________ and _______ to the matrix of the mitochondria. 2. NADH and FADH2 donate their high energy electrons to the ETC. NADH → NAD+ + + FADH2→ FAD + + (recycled) (go to intermembrane space) (passed to ETC) NADH FADH2 H+ e- 2H+ 2e-

3. Electrons are passed from carrier to carrier in the inner membrane. *(in prokaryotes ) 4. At the end of the chain, ________ is the 5. Oxygen uses the electron to the ETC is in the cell membrane Oxygen final electron acceptor. covalently bond with hydrogen forming water. (oxygen is reduced) Interactive link: Use ETS and Making ATP http://www.sp.uconn.edu/~terry/Common/respiration.html

B. Hydrogen Ion Movement 1. As the high energy electrons are transported down the chain, 2. It takes 3. The _____________ space becomes (+) positively charged. 4. The _______ becomes (-) negatively charged. their energy is used to push H+ from the matrix, through the inner membrane, to the intermembrane space. 2e- to move 1H+ intermembrane matrix

C. ATP Production 1. Hydrogen ions return to the matrix through the enzyme 2. As Hydrogen passes, the enzyme D. This process produces: - ATP synthase. grabs a phosphate and attaches it to ADP to become ATP. 34 ATP water

C. The Totals Per Glucose molecule ***note: each NADH produces __ ATP each FADH2 produces __ ATP 3 2 Click on ATP synthesis and play the first one only http://www.wiley.com/legacy/college/boyer/0470003790/animations/electron_transport/electron_transport.htm LOCATION ATP NADH FADH2 BYPRODUCTS GLYCOLYSIS KREBS CYCLE: Pyruvate oxidation → Energy Extraction → ELECTRON TRANSPORT CHAIN TOTALS (net) cytoplasm 2 2 ------ Carbon dioxide matrix 2 Carbon dioxide matrix 2 6 2 Inner Membrane (Cristae) 34 water 36 10 2 -2 ATP (transport of pyruvic acid into mitochondria)

D. Energy and Exercise (refer to activity sheet) E. Comparing Photosynthesis and Cellular Respiration Photosynthesis Cellular Respiration Function Location Reactants Products Equation Energy Release Energy Capture Chloroplasts Mitochondria H2O and CO2 C6H12O6 and O2 C6H12O6 and O2 H2O and CO2 6H2O + 6CO2 → C6H12O6 + 6O2 C6H12O6 + 6O2 → 6H2O + 6CO2

Section 9.3 Summary – pages 231-237 Comparing Photosynthesis and Cellular Respiration Photosynthesis Cellular Respiration Food synthesized Food broken down Energy from sun stored in glucose Energy of glucose released Carbon dioxide taken in Carbon dioxide given off Oxygen given off Oxygen taken in Produces sugars from PGAL Produces CO2 and H2O Requires light Does not require light Occurs only in presence of chlorophyll Occurs in all living cells Section 9.3 Summary – pages 231-237

California State Standards 1g. Students know the role of the mitochondria in making stored chemical-bond energy available to cells by completing the breakdown of glucose to carbon dioxide. 1i* Students know how chemiosmotic gradients in the mitochondria and chloroplasts store energy for ATP production.

Warm-up Section 9-1 What is cellular respiration? Draw a picture of a cell and label where glycolysis, krebs cycle, and ETC occur. What happens during the process of glycolysis?

Warm up section 9-2 What happens during the Krebs cycle. How are high energy electrons used by the electron transport chain? What pathways are taken by pyruvic acid if oxygen is not available?

Cytoplasm If oxygen is not present: Fermentation If oxygen is present: Pyruvic acid Lactic acid (or Alcohol & CO2 ) If oxygen is present: Cellular Respiration PGAL Pyruvic acid To ETC Cytoplasm