Cellular Respiration Aerobic Respiration

Let’s Review Anaerobic Respiration: Aerobic Respiration: Does not require Oxygen Aerobic Respiration: REQUIRES Oxygen Name 2 types of Fermentation 1. Alcoholic Fermentation 2. Lactic Acid Fermentation Where does GLYCOLOSIS occur in the cell? In the CYTOPLASM Do you need Oxygen for glycolysis? NO

Last time… We discussed that our CELLS need to produce ATP as a means on energy to function We begin this process by breaking down FOOD MOLECULES such as GLUCOSE in a process known as GLYCOLYSIS In the ABSENCE of oxygen, our cells perform anaerobic cellular respiration (FERMENTATION)

Glycolysis FIRST step in ALL TYPES of cellular Respiration Breaks down one Molecule of Glucose into 2 molecules of Pyruvate Where?: in the CYTOPLASM of the cell Produces a net amount of ATP USE 2 ATP to start (-2) Produces 4 ATP (+4) 4-2= 2 ATP

CYTOPLASM GLYCOLYSIS MITOCHONDRIA INPUTS: 1 Glucose 2 ATP OUTPUTS: http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html Glycolysis: No Oxygen Needed GLYCOLYSIS MITOCHONDRIA INPUTS: 1 Glucose 2 ATP OUTPUTS: 2 Pyruvates 4 ATP (2 net) CYTOPLASM

Glycolysis Energy In: 2 ATP Energy Out: 4 ATP NET 2 ATP Steps – A fuel molecule is energized, using ATP. Glucose 1 3 Step Glycolysis 1 Glucose-6-phosphate 2 Fructose-6-phosphate Energy In: 2 ATP 3 Fructose-1,6-diphosphate Step A six-carbon intermediate splits into two three-carbon intermediates. 4 4 Glyceraldehyde-3-phosphate (G3P) 5 Step A redox reaction generates NADH. 5 1,3-Diphosphoglyceric acid (2 molecules) 6 Steps – ATP and pyruvic acid are produced. 3-Phosphoglyceric acid (2 molecules) Energy Out: 4 ATP 6 9 7 2-Phosphoglyceric acid (2 molecules) 8 2-Phosphoglyceric acid (2 molecules) NET 2 ATP 9 Pyruvic acid (2 molecules per glucose molecule)

General Outline 1. Glycolysis Pyruvic Acid 2. Fermentation Glucose 1. Glycolysis Pyruvic Acid Oxygen Aerobic No Oxygen Anaerobic 2. Fermentation 2. Krebs Cycle Lactic Acid Fermentation 3. ETC Or Alcoholic Fermentation 36 ATP

Aerobic Respiration In AEROBIC respiration, Oxygen is present After Glycolysis, the Pyruvates produced enter the KREBS CYCLE (aka- Citric Acid Cycle) The next step after the Krebs Cycle is the ELECTRON TRANSPORT CHAIN

Krebs Cycle (AKA- Citric Acid Cycle Electron Transport Chain General Outline for Aerobic Respiration Net Products (per 1 glucose molecule) 2 Pyruvates 2 ATP Starts with GLYCOLYSIS Krebs Cycle (AKA- Citric Acid Cycle 2 ATP 6 NADH 2 FADH Then goes into Ends in Electron Transport Chain ~34 ATP

Pyruvate to Acetyl Co-A Pyruvate is converted into Acetyl Co-A which enters the Krebs Cycle This is done by a series of Redox reactions which involve the gaining or loss of electrons between NAD+ and NADH (electron carriers)

LEO the lion says GER Oxidation reactions are either a REDUCTION reaction or an OXIDATION reaction LEO: Lose Electron- Oxidation GER: Gain Electron- Reduction When NAD+ gains an H (NADH) it is reduced When NADH loses an H (NAD+) it is oxidized

Electron Carriers: NADH and FADH NADH and FADH are molecules that carry and transfer ELECTRONS This transfer of electrons is similar to how electricity works Think about how you get electricity to a hair dryer http://highered.mcgraw- hill.com/sites/0072507470/student_view0/chapter25/animation__how_t he_nad__works.html

2nd pathway: Krebs Cycle AKA- Citric Acid Cycle WHERE? In the MITOCHONDRIA MATRIX Each Pyruvate activates one turn in the cycle Thus, 1 glucose molecule = 2 pyruvates = 2 turns Products of Krebs: -CO2 -NADH -FADH -ATP

Krebs Cycle Products For every 1 glucose molecule (i.e- 2 pyruvates) Krebs produces: 2 ATP (energy!) 6 NADH (???) 2 FADH (???) 4 CO2 (by product) http://highered.mcgraw- hill.com/sites/0072507470/student_view0/chapter25/animation__how_t he_krebs_cycle_works__quiz_2_.html

3rd Pathway: Electron Transport Chain WHERE?: the INNER MEMBRANE of the Mitochondria -This is where the MOST ATP is generated through what we call oxidative phosphorylation -Electron carriers (NADH) transfer electrons along the membrane and a proton gradient forms, fueling the process to create ATP -the ETC produces between 32-34 ATP molecules http://highered.mcgraw- hill.com/sites/0072507470/student_view0/chapter25/animation__electron_transp ort_system_and_formation_of_atp__quiz_1_.html

Oxidative Phosphorylation (Chemiosmosis) Remember, Aerobic Respiration occurs when there is oxygen present Role of oxygen comes into play in the Electron Transport Chain When the electrons transfer through the membrane, they eventually get transferred to the Oxygen When O2 picks electrons up and then forms WATER by bonding to the H+ protons Oxygen is the ELECTRON ACCEPTER

ATP Synthase http://highered. mcgraw-hill Along the Mitochondria’s membrane, there are proteins aiding in the electron transport process One Protein is the ATP-making machine (ATP synthase) H+ ions pass down through ATP synthase, and allow the bonding of ADP to P to create ATP

Why do we care? Cyanide Poisoning Watch Video When Cyanide poisoning occurs, it stops the process of electron transfer at Cytochrome A3 (right before ATP synthase) ATP production stops Build up of Oxygen occurs Symptoms: flushed, red skin, rapid breathing, death within minuts

Respire to be a Millionaire Cell Respiration Song Because we love science in a song…. http://www.quia.com/rr/216170.html Respire to be a Millionaire

Summary of Cellular Respiration Reactions (make sure to know these!) Aerobic Cellular Respiration: C6H12O6+ 6O2  6CO2 +6H2O + (36-38ATP) (remember- it’s the reverse of photosynthesis!) Anaerobic Cellular Respiration: Alcoholic Fermentation: Glucose + (NADH)  Alcohol (i.e- ethanol) + CO2 + 2 ATP Lactic Acid Fermentation: Glucose + (NADH)  Lactic Acid + 2 ATP + (NAD+)