Table of Contents Chapter 7 Cellular Respiration Section 1 Glycolysis and Fermentation Section 2 Aerobic Respiration

Explain the functions of aerobic and anaerobic cellular respiration Section 2 Aerobic Respiration Chapter 7 Objectives Define cellular respiration, aerobic, anaerobic, mitochondria, glycolysis, fermentation Compare and contrast lactic acid fermentation and alcoholic fermentation Describe the role that each of the following plays in aerobic and anaerobic cellular respiration: Glucose (C6H12O6), ATP, ADP, Pyruvate, O2, lactic acid, ethanol Identify the reactants and products of aerobic and anaerobic cellular respiration Explain the functions of aerobic and anaerobic cellular respiration Predict changes in the process of cellular respiration if the reactants change.

Harvesting Chemical Energy Section 1 Glycolysis and Fermentation Chapter 7 Harvesting Chemical Energy Cellular respiration is the process by which cells break down organic compounds to produce ATP. Both autotrophs and heterotrophs use cellular respiration to make CO2 and water from organic compounds and O2. The products of cellular respiration are the reactants in photosynthesis; conversely, the products of photosynthesis are reactants in cellular respiration. Cellular respiration can be divided into two stages: glycolysis and aerobic respiration. Cellular respiration is the process of breaking sugar into a form that the cell can use as energy. This happens in all forms of life. Cellular respiration takes in food and uses it to create ATP. Usually, this process uses oxygen and is called aerobic respiration. Learn about aerobic respiration later

Photosynthesis-Cellular Respiration Cycle Section 1 Glycolysis and Fermentation Chapter 7 Photosynthesis-Cellular Respiration Cycle Overall reaction

Glycolysis Chapter 7 Section 1 Glycolysis and Fermentation Cellular respiration begins with glycolysis, which takes place in the cytosol of cells. During glycolysis, one six-carbon glucose molecule is oxidized to form two three-carbon pyruvic acid molecules. A net yield of two ATP molecules is produced for every molecule of glucose that undergoes glycolysis. “oxidized” chemical reaction that moves oxygen (oxygen is lost)

Glycolysis Chapter 7 Section 1 Glycolysis and Fermentation Two phosphates attach to 6-C glucose The six-carbon compound is split, two more phosphates The phosphates are removed, leaving behind two pyruvic acid (3C), and the phosphates add to four adp to make four atp 2 atp were used, but 4 were created (so a little bit of atp is made during glycolysis)

Fermentation Chapter 7 Section 1 Glycolysis and Fermentation If oxygen is not present, some cells can convert pyruvic acid into other compounds through additional biochemical pathways that occur in the cytosol. The combination of glycolysis and these additional pathways is fermentation. Fermentation does not produce ATP, but it does regenerate NAD+, which allows for the continued production of ATP through glycolysis. When a cell uses sugars for energy when oxygen is not available

Chapter 7 Section 1 Glycolysis and Fermentation Cellular respirations vs fermentation Both start with glycolysis We will talk about aerobic respiration later

Fermentation, continued Section 1 Glycolysis and Fermentation Chapter 7 Fermentation, continued Lactic Acid Fermentation In lactic acid fermentation, an enzyme converts pyruvic acid into another three-carbon compound, called lactic acid. Muscles during strenuous exercise: muscle cells use up O quicker than it can be delivered to them, switch to lactic acid fermentation. lactic acid builds up in cells, causing some fatigue or cramps until it is taken away by the blood supply In cheese making, fungi or bacteria are added to milk, lactic acid fermentation converts sugars in the milk to lactic acid This is also what happens when milk goes sour in the fridge or forms clumps

Fermentation, continued Section 1 Glycolysis and Fermentation Chapter 7 Fermentation, continued Alcoholic Fermentation Some plants and unicellular organisms, such as yeast, use a process called alcoholic fermentation to convert pyruvic acid into ethyl alcohol and CO2.

Two Types of Fermentation Section 1 Glycolysis and Fermentation Chapter 7 Two Types of Fermentation

Fermentation, continued Section 1 Glycolysis and Fermentation Chapter 7 Fermentation, continued Through glycolysis, only about 2 percent of the energy available from the oxidation of glucose is captured as ATP. Much of the energy originally contained in glucose is still held in pyruvic acid. Glycolysis alone or as part of fermentation is not very efficient at transferring energy from glucose to ATP. Last slide

Explain the functions of aerobic and anaerobic cellular respiration Section 2 Aerobic Respiration Chapter 7 Objectives Define cellular respiration, aerobic, anaerobic, mitochondria, glycolysis, fermentation Compare and contrast lactic acid fermentation and alcoholic fermentation Describe the role that each of the following plays in aerobic and anaerobic cellular respiration: Glucose (C6H12O6), ATP, ADP, Pyruvate, O2, lactic acid, ethanol Identify the reactants and products of aerobic and anaerobic cellular respiration Explain the functions of aerobic and anaerobic cellular respiration Predict changes in the process of cellular respiration if the reactants change.

Overview of Aerobic Respiration Section 2 Aerobic Respiration Chapter 7 Overview of Aerobic Respiration Aerobic respiration is the process in which pyruvic acid from glycolysis is broken down to make a large amount of ATP in the presence of oxygen. In eukaryotic cells, the processes of aerobic respiration occur in the mitochondria. Aerobic respiration only occurs if oxygen is present in the cell. Pyruvic acid from glycolysis diffuses into the mitochondria, meanwhile reacting with molecules to form acetyl CoA. Aerobic vs anaerobic Fermentation is anaerobic, takes place in absence of oxygen Where in the cell does glycolysis take place? (cytosol)

Stages of aerobic respiration Section 2 Aerobic Respiration Chapter 7 Stages of aerobic respiration During the Krebs cycle (the citric acid cycle), two molecules of CO2 are given off, one molecule of ATP is formed, electron carriers gain electrons to donate to the electron transport chain The bulk of the energy released by the oxidation of glucose still has not been transferred to ATP.

stages of Aerobic Respiration Section 2 Aerobic Respiration Chapter 7 stages of Aerobic Respiration As protons move through ATP synthase and down their concentration and electrical gradients, ATP is produced. Oxygen combines with the electrons and protons to form water. Electron transport chain Like charging a battery, as electrons move through the electron transport chain, the concentration of electrons builds up on one side of the membrane (concentration gradient). Then as the electrons flow through ATP synthase, ATP is produced (34 molecules of ATP) Water is also formed here Same process as the light dependent reaction of photosynthesis in the thylakoid membrane

Efficiency of Cellular Respiration Section 2 Aerobic Respiration Chapter 7 Efficiency of Cellular Respiration Cellular respiration can produce up to 38 ATP molecules from the oxidation of a single molecule of glucose. Most eukaryotic cells produce about 36 ATP molecules per molecule of glucose. Thus, cellular respiration is nearly 20 times more efficient than glycolysis alone.

A Summary of Cellular Respiration Section 2 Aerobic Respiration Chapter 7 A Summary of Cellular Respiration Another Role of Cellular Respiration Providing cells with ATP is not the only important function of cellular respiration. Molecules formed at different steps in glycolysis and the Krebs cycle are often used by cells to make compounds that are missing in food.

Summary of Cellular Respiration Section 2 Aerobic Respiration Chapter 7 Summary of Cellular Respiration

Chapter 7 Section 1 Glycolysis and Fermentation Cellular respirations vs fermentation Both start with glycolysis