Cellular Respiration

A quick review… A quick review… When we eat, we get ______ from glucose and other sugars When we eat, we get ______ from glucose and other sugars Food energy is c_______ into usable energy Food energy is c_______ into usable energy Energy used to bond phosphate groups to ADP to make _____. Energy used to bond phosphate groups to ADP to make _____.

Cellular Respiration Cellular Respiration What is cell respiration??? What is cell respiration??? Respiration: the process of breaking down food molecules into usable energy Respiration: the process of breaking down food molecules into usable energy THE GOAL: THE GOAL: Create ATP for cells to use Create ATP for cells to use Free up electrons—have high energy Free up electrons—have high energy

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy (ATP + heat) 2234

Cellular Respiration Types of cell respiration Types of cell respiration Aerobic Processes: Aerobic Processes: REQUIRE oxygen to take place REQUIRE oxygen to take place A lot of energy available (efficient) A lot of energy available (efficient) Anaerobic Processes: Anaerobic Processes: DO NOT require oxygen to take place DO NOT require oxygen to take place Get energy quickly (inefficient) Get energy quickly (inefficient)

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Glycolysis Involves breaking down 6-carbon sugars Involves breaking down 6-carbon sugars Break sugars into pyruvic acid molecules Break sugars into pyruvic acid molecules 3-Carbon molecules 3-Carbon molecules This process is ANAEROBIC This process is ANAEROBIC No oxygen necessary No oxygen necessary Occurs in the cytoplasm of cells Occurs in the cytoplasm of cells

Glycolysis You will need to know this… You will need to know this…

Glycolysis Just Kidding… Just Kidding…

Glycolysis Glycolysis also creates hydrogen ions and free electrons Glycolysis also creates hydrogen ions and free electrons The whole point of respiration = high energy The whole point of respiration = high energy H + ions bond with NAD + to form NADH + H + H + ions bond with NAD + to form NADH + H + NADH carries electrons and H + ions NADH carries electrons and H + ions This process uses 2 ATP but This process uses 2 ATP but creates 4 ATP molecules

Glycolysis

Glycolysis TOTAL ATP PRODUCTION: TOTAL ATP PRODUCTION: Glycolysis Step 1 uses 2 ATP molecules Glycolysis Step 1 uses 2 ATP molecules Glycolysis Step 2 converts 4 ADP molecules into 4 ATP molecules Glycolysis Step 2 converts 4 ADP molecules into 4 ATP molecules Net ATP production = 2 ATP for every glucose molecule Net ATP production = 2 ATP for every glucose molecule

Glycolysis Oxygen is our friend… Oxygen is our friend… When oxygen is present, aerobic respiration occurs When oxygen is present, aerobic respiration occurs Happens in the mitochondria Happens in the mitochondria

Glycolysis Breaking down Pyruvic Acid… Breaking down Pyruvic Acid… Occurs in the mitochondria Occurs in the mitochondria Pyruvic Acid = 3-carbon compound Pyruvic Acid = 3-carbon compound Broken down into… Broken down into… 2-Carbon compound—acetic acid 2-Carbon compound—acetic acid Carbon Dioxide Carbon Dioxide

Glycolysis Intermediate Step in Glycolysis Intermediate Step in Glycolysis 2-Carbon Compound—Acetic Acid 2-Carbon Compound—Acetic Acid Combined with coenzyme A (CoA) Combined with coenzyme A (CoA) Forms compound called acetyl-CoA Forms compound called acetyl-CoA This is only an intermediate step—have to move pyruvic acid into Krebs Cycle This is only an intermediate step—have to move pyruvic acid into Krebs Cycle

Glycolysis Glycolysis = 2 ATP

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Citric Acid (Krebs) Cycle Produces more ATP and releases more electrons Produces more ATP and releases more electrons Electrons picked up by NAD + and FAD Electrons picked up by NAD + and FAD Organic carrier molecules Organic carrier molecules Occurs inside mitochondria Occurs inside mitochondria Mitochondrial Matrix Mitochondrial Matrix

Citric Acid (Krebs) Cycle Acetyl CoA combines with a 4-carbon molecule to form a 6-carbon molecule Acetyl CoA combines with a 4-carbon molecule to form a 6-carbon molecule Citric Acid Citric Acid NAD becomes NADH NAD becomes NADH FADH becomes FADH 2 FADH becomes FADH 2 CO 2 released CO 2 released ATP is created ATP is created The cycle starts again The cycle starts again

Citric Acid (Krebs) Cycle

Citric Acid Cycle = 2 ATP Citric Acid (Krebs) Cycle

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Electron Transport Chain What is the ETC??? What is the ETC??? A series of molecules along which electrons are transferred, releasing energy A series of molecules along which electrons are transferred, releasing energy Occurs in the mitochondria— mitochondrial matrix Occurs in the mitochondria— mitochondrial matrix Aerobic process Aerobic process Oxygen is involved Oxygen is involved Acts as the electron acceptor Acts as the electron acceptor

Electron Transport Chain Transport As the electrons are passed between carrier proteins, energy is released As the electrons are passed between carrier proteins, energy is released ATP is created ATP is created Carbon is given off as carbon dioxide Carbon is given off as carbon dioxide

Electron Transport Chain

ETC = 34 ATP

Electron Transport Chain A problem exists if there is no oxygen A problem exists if there is no oxygen Anaerobic process Anaerobic process When oxygen is used up, electrons cannot be removed When oxygen is used up, electrons cannot be removed Traffic jam in the mitochondria Traffic jam in the mitochondria KEY POINT —Electron Transport Chain cannot run without oxygen KEY POINT —Electron Transport Chain cannot run without oxygen

Anaerobic Respiration If no oxygen present after glycolysis, pyruvic acid can still be broken down If no oxygen present after glycolysis, pyruvic acid can still be broken down This is Fermentation This is Fermentation Only 2 ATP made during fermentation Only 2 ATP made during fermentation Uses electrons carried by NADH + H + so that NAD + can regenerate for glycolysis Uses electrons carried by NADH + H + so that NAD + can regenerate for glycolysis

Anaerobic Respiration

**Two types of fermentation **Two types of fermentation Lactic Acid Fermentation Lactic Acid Fermentation Alcoholic Fermentation (Yeast) Alcoholic Fermentation (Yeast) Glucose 2 Pyruvic Acid 2 Lactic Acid Glucose 2 Pyruvic Acid 2 Ethanol + 2 CO 2

Anaerobic Respiration Lactic Acid Fermentation Lactic Acid Fermentation Muscle fatigue Muscle fatigue When your muscle cells require more energy than can be produced When your muscle cells require more energy than can be produced Lack of oxygen Lack of oxygen Lactic acid build up = muscle fatigue Lactic acid build up = muscle fatigue When oxygen is present, lactic acid breaks down When oxygen is present, lactic acid breaks down

Anaerobic Respiration

Alcohol Fermentation Alcohol Fermentation Occurs in bacteria, plants and most animals Occurs in bacteria, plants and most animals Can you think of a bacteria that is used for fermentation??? Can you think of a bacteria that is used for fermentation??? Pyruvic Acid is converted into ethanol and carbon dioxide Pyruvic Acid is converted into ethanol and carbon dioxide

Anaerobic Respiration

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Cellular Respiration General Formula C 6 H 12 O O 2 6 CO H 2 O

Often, in attempts to simplify, false paradigms are created. Some textbooks do this when introducing biochemical reactions. Photosynthesis Respiration