Respiration Respiration Respiration the process by which food

Respiration

Respiration • Respiration the process by which food molecules are broken down – Food molecules are 6 -carbons sugars – You take in food which is digested and broken down into 6 -carbon sugars – Plants can’t “eat” so they make 6 -carbon sugars with photosynthesis – Mitochondria then transform the “food energy” into chemical energy

Respiration • A 6 -carbon sugar contains an enormous amount of energy (for a cell) • Mitochondria “make change” energetically • Take the energy in a sugar and convert it into more conveniently-sized packages

Respiration C 6 H 12 O 6 + 6 O 2 → 6 CO 2 + 6 H 2 O + energy Carbohydrate Oxygen Carbon dioxide Water

Respiration • Aerobic respiration: processes that require oxygen in order to take place • Anaerobic respiration: processes that do not require oxygen

Aerobic Respiration • • Step 1: Glycolysis Step 2: Breakdown of pyruvic acid Step 3: Citric acid cycle Step 4: Electron transport chain

Respiration CYTOPLASM: Glycolysis MATRIX: Breakdown of pyruvic acid, Citric acid cycle Outer membrane INNER MEMBRANE: Electron transport chain

Step 1: Glycolysis • Occurs in cytoplasm • Does not require oxygen • Involves splitting a glucose (6 -carbon sugar) into 2 3 -carbon molecules: pyruvic acid

Step 1: Glycolysis • Also produces H+ ions and energizes electrons which are captured by NAD+, forming NADH + H+

Step 1: Glycolysis Glucose

Step 1: Glycolysis 2 ATP Glucose 2 ADP

Step 1: Glycolysis 2 ATP 2 ADP P Glucose P 2 PGAL

Step 1: Glycolysis 2 ATP 2 ADP 4 ADP + 4 Pi 4 ATP P Glucose 2 NAD+ 2 NADH + 2 H+ P 2 PGAL

Step 1: Glycolysis 2 ATP 2 ADP 4 ADP + 4 Pi 4 ATP P Glucose 2 NAD+ 2 NADH + 2 H+ P 2 PGAL 2 Pyruvic acid

Step 1: Glycolysis • Net yeild – 2 ATP (uses 2, produces 4) – 2 NADH – 2 pyruvic acid

Aerobic Respiration ü Step 1: Glycolysis • Step 2: Breakdown of pyruvic acid • Step 3: Citric acid cycle • Step 4: Electron transport chain

Step 2: Breakdown of Pyruvic Acid • Occurs when pyruvic acid (from glycolysis) enters the mitochondrial matrix • Requires oxygen – If there is no oxygen present pyruvic acid enters fermentation

Step 2: Breakdown of Pyruvic Acid • Involves breaking CO 2 off pyruvic acid • Remaining portion of pyruvic acid combines with coenzyme A to form acetyl. Co. A

Step 2: Breakdown of Pyruvic Acid • Also produces H+ and energizes electrons which are captured by NAD+, to form NADH + H+

Step 2: Breakdown of Pyruvic Acid Mitochondrial membrane To citric acid cycle “Exhaled”

Step 2: Breakdown of Pyruvic Acid • Net yeild – 2 NADH – Acetyl-Co. A

Aerobic Respiration ü Step 1: Glycolysis ü Step 2: Breakdown of pyruvic acid • Step 3: Citric acid cycle • Step 4: Electron transport chain

Step 3: Citric Acid Cycle • Occurs in mitochondrial matrix • Acetyl-Co. A is transformed into citric acid through a series of reactions

Step 3: Citric Acid Cycle • More ATP and CO 2 are produced • More H+ are produced and electrons are energized • NAD+ and FAD capture them to form NADH + H+ and FADH

Step 3: Citric Acid Cycle 4 C 6 C – Citric acid CITRIC ACID CYCLE 5 C

Step 3: Citric Acid Cycle • Net yield – 2 ATP – 6 NADH – 2 FADH 2

Aerobic Respiration ü Step 1: Glycolysis ü Step 2: Breakdown of pyruvic acid ü Step 3: Citric acid cycle • Step 4: Electron transport chain

Step 4: Electron Transport Chain • Happens on inner membrane of mitochondria • Occurs only if oxygen is present – Oxygen is final electron acceptor – If no oxygen is present reaction stops

Step 4: Electron Transport Chain • Electrons come from NADH and FADH molecules which gathered them during glycolysis and CTA • Energy from electrons is used to add Pi to ADP, forming ATP • At the end of the chain, oxygen accepts the electrons and combines with 2 H+ ions to form water

Step 4: Electron Transport Chain Outer mitochondrial membrane Electron transport chain Cytochromes Intermembrane space Inner mitochondrial membrane Cytochromes

Step 4: Electron Transport Chain • Net yeild – 32 ATP

Aerobic Respiration • • Step 1: Glycolysis Step 2: Breakdown of pyruvic acid Step 3: Citric acid cycle Step 4: Electron transport chain

Aerobic Respiration Glycolysis 2 ATP Citric acid cycle 2 ATP Electron transport chain **32 ATP **Makes ATP from electrons carried to it from the first 3 steps

Aerobic Respiration Makes 36 ATP

Anaerobic Respiration • Pyruvic acid molecules are still formed through glycolysis • Broken down differently: – No ATP is produced after glycolysis – NAD+ is regenerated so glycolysis can continue

Anaerobic Respiration • 2 types: – Lactic acid fermentation – Alcoholic fermentation

Lactic Acid Fermentation • Lactic acid is end product • Occurs when muscles require energy at a faster rate than it can be supplied through aerobic respiration • Causes burning sensation in muscles

Lactic Acid Fermentation Glycolysis

Lactic Acid Fermentation

Lactic Acid Fermentation • Net yield – 2 ATP

Alcoholic Fermentation • Ethyl alcohol and CO 2 are end products • Occurs in organisms that live in environments lacking oxygen • Source of bubbles in beer and champagne and causes baking bread to rise

Alcoholic Fermentation Glycolysis

Alcoholic Fermentation Glycolysis 2 CO 2 2 Ethanol

Comparison of Aerobic Respriation and Fermentation • How many ATP does aerobic respiration produce? • How many ATP does fermentation produce? 36 ATP 2 ATP

WE’RE DONE!!!!

Step 1: Glycolysis 2 ATP 2 ADP 4 ADP + 4 Pi P Glucose 2 NAD+ P 2 PGAL 2 Pyruvic acid

Step 2: Breakdown of Pyruvic Acid To citric acid cycle “Exhaled”

Step 3: Citric Acid Cycle 4 C 6 C – Citric acid CITRIC ACID CYCLE 4 C 5 C

Step 4: Electron Transport Chain Outer mitochondrial membrane Electron transport chain Cytochromes Intermembrane space Inner mitochondrial membrane Cytochromes

Lactic Acid Fermentation Glycolysis

Alcoholic Fermentation Glycolysis 2 CO 2 2 Ethanol