Cellular Respiration

 Both autotrophs and heterotrophs use the compounds in food for energy sources.  Autotrophs make their own glucose.  Heterotrophs cannot.  The process by which glucose molecules are broken down to release energy (ATP) is cellular respiration.  Both autotrophs and heterotrophs use the compounds in food for energy sources.  Autotrophs make their own glucose.  Heterotrophs cannot.  The process by which glucose molecules are broken down to release energy (ATP) is cellular respiration.

Cellular Respiration  The process by which glucose molecules are broken down to release energy is cellular respiration.  It is a series of chemical reactions that produces ATP. Most cellular processes use ATP for energy.  The process by which glucose molecules are broken down to release energy is cellular respiration.  It is a series of chemical reactions that produces ATP. Most cellular processes use ATP for energy.

Two types of Respiration  There are two types of cellular respiration.  Aerobic - requires oxygen  Produces 36 ATP from each glucose  Anaerobic - takes place without oxygen  Produces 2 ATP from each glucose  There are two types of cellular respiration.  Aerobic - requires oxygen  Produces 36 ATP from each glucose  Anaerobic - takes place without oxygen  Produces 2 ATP from each glucose

Anaerobes  Anaerobes are organisms that use the anaerobic respiration pathway.  Most anaerobes are bacteria.  Anaerobes do NOT require oxygen.  Anaerobes are organisms that use the anaerobic respiration pathway.  Most anaerobes are bacteria.  Anaerobes do NOT require oxygen.

Aerobes  Aerobes are organisms that use the aerobic respiration pathway.  Aerobes require oxygen.  Aerobes are organisms that use the aerobic respiration pathway.  Aerobes require oxygen.

Stages of Respiration  The first stage of respiration for all living organisms, anaerobes or aerobes, is called glycolysis and it takes place in the cytosol.

Glycolysis  Glyco means “glucose/sugar”  Lysis means “to split”   glycolysis means “to split glucose”  Glyco means “glucose/sugar”  Lysis means “to split”   glycolysis means “to split glucose”

Glycolysis Glucose C 6 H 12 O 6  Two pyruvate (3-C) molecules Two ATP Two NADH Glucose C 6 H 12 O 6  Two pyruvate (3-C) molecules Two ATP Two NADH

Stages of Respiration  The second stage in aerobic respiration is the Krebs cycle, which occurs in the mitochondria.  Pyruvate is converted to Acetyl-CoA, which enters the Krebs cycle. The Acetyl-CoA is broken down to form CO 2, ATP, NADH, and FADH 2.  The second stage in aerobic respiration is the Krebs cycle, which occurs in the mitochondria.  Pyruvate is converted to Acetyl-CoA, which enters the Krebs cycle. The Acetyl-CoA is broken down to form CO 2, ATP, NADH, and FADH 2.

Stages of Respiration  In the Krebs cycle, the pyruvate is converted to acetyl-CoA, which is broken down to form CO 2, ATP, NADH, and FADH 2.  One ATP is produced for each pyruvate.  CO 2 is a byproduct.  why we breathe out carbon dioxide!  In the Krebs cycle, the pyruvate is converted to acetyl-CoA, which is broken down to form CO 2, ATP, NADH, and FADH 2.  One ATP is produced for each pyruvate.  CO 2 is a byproduct.  why we breathe out carbon dioxide!

Stages of Respiration  So, after glycolysis and the Krebs cycle, there are 4 ATP produced from each glucose.  There’s still 32 ATP left to get from the process (because aerobic produces a total of 36 ATP from each glucose).  So, after glycolysis and the Krebs cycle, there are 4 ATP produced from each glucose.  There’s still 32 ATP left to get from the process (because aerobic produces a total of 36 ATP from each glucose).

Electron Transport Chain  The rest of the energy is contained in electrons carried by NADH and FADH 2.  Electron transport is the process by which energy is transferred from NADH and FADH 2 to ATP. This phase is also in the mitochondria.  The rest of the energy is contained in electrons carried by NADH and FADH 2.  Electron transport is the process by which energy is transferred from NADH and FADH 2 to ATP. This phase is also in the mitochondria.

Aerobic Respiration  C 6 H 12 O 6 + 6O 2  glucose oxygen 6CO 2 + 6H 2 O + energy carbon water ATP dioxide  C 6 H 12 O 6 + 6O 2  glucose oxygen 6CO 2 + 6H 2 O + energy carbon water ATP dioxide

Aerobic Respiration  Compare the reactants and products of photosynthesis and cellular respiration.  The reactants of one process are the products of the other!  Compare the reactants and products of photosynthesis and cellular respiration.  The reactants of one process are the products of the other!

Anaerobic Respiration  Anaerobic respiration does NOT require oxygen.  The 2 most common forms are:  Alcoholic fermentation  Lactic acid fermentation

Alcoholic Fermentation  Is carried out by yeast, a kind of fungus  Does not require oxygen  Uses only glycolysis  Pyruvate + NADH  Ethanol + NAD + + CO2  Is carried out by yeast, a kind of fungus  Does not require oxygen  Uses only glycolysis  Pyruvate + NADH  Ethanol + NAD + + CO2

Alcoholic Fermentation  Uses:  Baking  Wine and beer industry  Ethanol  Swiss cheese  Uses:  Baking  Wine and beer industry  Ethanol  Swiss cheese

Lactic Acid Fermentation  Uses only glycolysis  Does not require oxygen  Pyruvate + NADH  Lactic Acid + CO2  Uses only glycolysis  Does not require oxygen  Pyruvate + NADH  Lactic Acid + CO2

Lactic Acid Fermentation  Carried out by human muscle cells when they are oxygen- deprived.  Lactic acid is a toxin and causes fatigue, soreness, and stiffness in muscles.  Carried out by human muscle cells when they are oxygen- deprived.  Lactic acid is a toxin and causes fatigue, soreness, and stiffness in muscles.