Do now Pick up 10 alaska peas Put in a plastic ziplock bag with your name on it HW: Germinate them :) http://www.instructables.com/id/Start-Seeds-Without-Soil/step3/Bottle-it-Up-and-Place/ Bring them in next class for our lab

Cellular Respiration 2.8, 8.2

2.8 Cellular Respiration SL Understanding (Statement objectives) Define cell respiration. Cell respiration is the controlled release of energy from organic compounds to produce ATP. ATP from cell respiration is immediately available as a source of energy in the cell. Explain anaerobic cell respiration. Anaerobic cell respiration gives a small yield of ATP from glucose. Explain aerobic cell respiration- include the link reaction, the Krebs cycle, the role of NADH+ H+, the electron transport chain, and the role of oxygen. Aerobic cell respiration requires oxygen and gives a large yield of ATP from glucose. Applications Explain the use of anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking. Details of the metabolic pathways of cell respiration are not needed but the substrates and final waste products should be known. Describe lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions. Nature of science Assess the ethics of scientific research—the use of invertebrates in respirometer experiments has ethical implications. Skills Analyze results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using a respirometer. There are many simple respirometers which could be used. Students are expected to know that an alkali is used to absorb CO2, so reductions in volume are due to oxygen use. Temperature should be kept constant to avoid volume changes due to temperature fluctuations. Outline the process of glycolysis, including phosphorylation, lysis, oxidation, and ATP formation (in this order). Explain the relationship between the structure of the mitochondrion and its function.

8.2 Cellular Respiration HL Understanding Cell respiration involves the oxidation and reduction of electron carriers. Phosphorylation of molecules makes them less stable. In glycolysis, glucose is converted to pyruvate in the cytoplasm. Glycolysis gives a small net gain of ATP without the use of oxygen. In aerobic cell respiration pyruvate is decarboxylated and oxidized, and converted into acetyl compound and attached to coenzyme A to form acetyl coenzyme A in the link reaction. In the Krebs cycle, the oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating carbon dioxide. The names of the intermediate compounds in glycolysis and the Krebs cycle are not required. Energy released by oxidation reactions is carried to the cristae of the mitochondria by reduced NAD and FAD. Transfer of electrons between carriers in the electron transport chain in the membrane of the cristae is coupled to proton pumping. In chemiosmosis protons diffuse through ATP synthase to generate ATP. Oxygen is needed to bind with the free protons to maintain the hydrogen gradient, resulting in the formation of water. The structure of the mitochondrion is adapted to the function it performs. Applications Explain how electron tomography is used to produce images of active mitochondria. Nature of science Paradigm shift—Describe the chemiosmotic theory that led to a paradigm shift in the field of bioenergetics. Skills Analyze diagrams of the pathways of aerobic respiration to deduce where decarboxylation and oxidation reactions occur. Annotate a diagram of a mitochondrion to indicate the adaptations to its function.

Cellular Respiration Cell respiration is the controlled release of energy from organic compounds to produce ATP

Cellular Respiration Catabolic, energy yielding pathway Breaks down energy rich molecules, such as glucose releasing energy for the synthesis of ATP Aerobic respiration requires oxygen Forms of respiration that do not require oxygen are anaerobic more on this later

Energy as A Result of Cell Resp Aerobic respiration has a large yield of ATP This is immediately available as a source of energy within the cell What is this energy used for?

Before We Get Started: Redox Oxidation Reduction Electrons Lost Gained Energy H+ Oxygen

Remembering Redox L E O goes G E R o s i n g l e c t r o n s x i d a t u c t i o n

Electron carriers

Electron carriers electron carriers

Aerobic Respiration Summarized

Glycolysis Occurs in the cytoplasm “Sugar splitting” 1 glucose (6C sugar) 2 pyruvate (3C acid) This step of respiration is anaerobic

Glycolysis Phosphorylation: 2 ATP is used to add phosphate groups to each end. Phosphorylation makes molecules less stable. Lysis: Phosphorylated sugar splits into 2 3C sugars (triose phosphates) 2 NAD+ 4 ADP Oxidation + ATP Formation: Hydrogen removed from triose phosphates via oxidation. NAD+ is reduced to NADH + H+. 4 ATP produced 2 NADH + H+ 4 ATP

1.Phosphorylation 2.Lysis 3.Oxidation

Glycolysis Yield Net 2 ATP (4 produced, 2 used) 2 NADH + H+ 2 pyruvate molecules Glycolysis gives a small net gain of ATP without the use of oxygen It is actually a complicated process

Mitochondria Structure

Stop draw and explain Redox reactions Glycolysis Mitochondria

Transition Reaction Occurs in the mitochondrial matrix Link between glycolysis and the Krebs cycle Pyruvate 1C (as Co2) NADH + H+ Pyruvate is decarboxylated 2C Acetyl + Coenzyme A Acetyl CoA

Important to Know about Transition Reaction Pyruvate is decarboxylated and oxidized Pyruvate is converted into acetyl compound and attached to coenzyme A to form acetyl coenzyme A

The Krebs Cycle: 1 Turn Location: Mitochondrial Matrix Acetyl CoA Coenzyme A returns to link reaction and is reused Acetyl 2C compound Acetyl Compound (2C) combines with oxaloacetate (4C) to form citrate(6C) Note: 1 turn of the Krebs cycle is for 1 pyruvate. Therefore 2 turns of the Krebs cycle are necessary per molecule of glucose Oxaloacetate (4C) Citrate (6C) 3 NADH 1 ATP 2 Carbons lost as CO2 1 FADH2

The Krebs Cycle In the Krebs cycle, the oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating carbon dioxide What does this mean? citrate is oxidized NAD is reduced to NADH FAD is reduced to FADH2 Remember: gaining a hydrogen is reduction Carbon dioxide is given off

The Krebs Cycle Yield Per Pyruvate Per Glucose (2 turns) CO2 2 4 ATP 1 NADH 3 6 FADH2

review

Stop - draw and explain Transition reaction and krebs cycle

The Electron Transport Chain

Electron Transport Chain Final stage of cellular respiration What is the electron transport chain? A series of hydrogen and electron carriers, located on the membranes of the mitochondrial cristae This final stage involve oxidative phosphorylation and ATP generation What is oxidative phosphorylation????

Electron Transport Chain Consists of many linked proteins embedded in the cristae These proteins are electron carriers and are reduced and oxidized as they accept and donate electrons Inter-membrane space Mitochondrial matrix

Where does the energy come from? “Energy released by oxidation reactions is carried to the cristae of the mitochondria by reduced NAD and FAD” Electrons from glycolysis and the Krebs cycle are transported the ETC as NADH and FADH2 The hydrogens or electrons donated from NADH and FADH2 are passed from one carrier protein to the next http://www.science.smith.edu/departments/Biology/Bio231/etc.html

Electron Transport Chain Oxygen is the final electron acceptor It is reduced to water The ETC yields 34 ATP and water

Chemiosmosis in the ETC The energy released from the electrons is used to pump H+ ions across the membrane (against the concentration gradient) The protons move from the mitochondrial matrix to the inter-membrane space

Proton pumping in the ETC

Chemiosmosis in the ETC The buildup of protons in the inter-membrane space creates a proton gradient Transfer of electrons between carriers in the ETC is coupled to proton pumping

Chemiosmosis in the ETC In order to even out the proton concentration, electrons flow back into the mitochondrial matrix with the concentration gradient Protons flow down with the assistance of an enzyme called ATP synthase As protons flow down, ADP is phosphorylated, producing ATP

Chemiosmosis: protons flow through ATP synthase

Role of Oxygen In the ETC, oxygen is needed to bind with the free protons to maintain the hydrogen gradient results in the formation of water

Note About Chemiosmosis Proposed by Peter Mitchell- faced years of opposition before finally accepted TOK: Why does the disproof of an old theory sometimes take a long time before the acceptance of a new one?

Stop- draw and explain ETC chemiosmosis oxidative phosphorylation

Structure of Mitochondria

Mitochondria Structure Adapted to Function •Matrix creates an isolated space which contains the enzymes for the Krebs cycle to occur. •Cristae folds increase the surface area for electron transfer system. •The double membrane creates a small space into which the H+ can be concentrated. (barrier) •Embedded in the membrane are the enzymes and other necessary compounds for the processes of the electron transport chain and chemiosmosis to occur.

Electron Tomography Provides an image of active mitochondria

Review More review

Do Now Get goggles In a group of three or four prepare a 40 degree water bath 5% glucose solution is on the cart yeast suspension is in the water bath follow steps 1-10 of the lab look at the picture and the model set up come back to your desks for 10 minute incubation

But first a little review

Explain aerobic respiration including oxidative phosphorylation Big essay :) Explain aerobic respiration including oxidative phosphorylation

Back to lab step 11 and 12

Fermentation Anaerobic process All organisms can metabolize glucose anaerobically (glycolysis) Fermentation pathways do not use oxygen as a final electron acceptor Fermentation has no further yield in ATP

Fermentation continued If oxygen is not present to be the final electron acceptor (remember, anaerobic), then there must be an alternative electron acceptor otherwise glycolysis will stop What’s the point? To replenish NAD+ for glycolysis to continue glycolysis has small yield of ATP

2 Types of Fermentation Lactic Acid Fermentation Results in production of lactic acid Occurs in animals Alcoholic Fermentation Results in production of ethanol and carbon dioxide

Lactic Acid Fermentation Occurs in animals Why your muscles may “burn” after you work out Lactic acid is toxic so this pathway cannot continue indefinitely The liver converts lactic acid back into a harmless respiratory intermediate

Lactic Acid Fermentation Lactate production in humans when anaerobic respiration is used maximizes the power of muscle contractions When does this happen?

Alcoholic Fermentation Occurs in yeast, some bacteria and higher plant cells

Alcoholic Fermentation Use Alcoholic fermentation produces ethanol and carbon dioxide these products are useful to the baking (CO2 for bread and other goods to rise) and brewing (ethanol in alcoholic beverages) industries Think of how yeast is used when making bread

http://www.phschool.com/atschool/phbio/active_art/cellular_respiration/

Finish lab QUIZ NEXT CLASS Respiration and fermentation