Cellular Respiration What is it? extracting the energy from glucose and using it to charge ADP to make ATP Who performs cell respiration? One way or another, EVERY LIVING THING

What’s the BIG PICTURE Well…that depends on the conditions. –If there is no oxygen (or no mitochondria), only steps in the cytoplasm happen –With O2 more energy can be “extracted” from glucose to put into ATP molecules

Cellular Respiration –What are the steps? –Anaerobic cell respiration Glycolysis + Fermentation –Aerobic cell respiration Glycolysis + Krebs Cycle + ETC Purpose is the same, just different methods.

Cell Respiration - Two types - Anaerobic respiration: O2 not needed; - done by yeast, certain bacteria, exhausted muscle cells of animals - produces 2 ATP per glucose - Two steps: - glycolysis - fermentation: alcohol or lactic acid

Step 1 Glycolysis – “glucose splitting” –Glucose split into 2 pyruvate –2 ATP used –4 ATP and 2 NADH made –Happens in cytoplasm –First step of BOTH ANAEROBIC AND AEROBIC RESPIRATION

Steps Fermentation – - conversion of pyruvate to Alcohol and CO2 (yeast) or Lactic acid (exhausted muscle cells) - no more ATP generated - Purpose: “empties” electron carriers so glycolysis can happen again

Cell Respiration - SECOND type - Aerobic respiration: O2 needed -Requires mitochondria -Produces 36 ATP per glucose -Three steps: -Glycolysis (followed by shuttle step) -Krebs -Electron transport Chain

+ 6O  6CO 2 + 6H 2 O - getting the energy back out of storage C6H12O6 ADP + P ATP Equation for Aerobic C. R. The equation that we use for cellular respiration is really AEROBIC cell respiration

Mitochondria Krebs cycle takes place in the matrix – Purpose: to break apart C-C and C-H bonds –Energy transferred to electron carriers and a few ATP

Aerobic Respiration Steps

Step 1 Glycolysis: EXACTLY the same as the beginning of anaerobic respiration –BUT next step is different…

Step 1.5 Shuttle step– converts pyruvate to Acetyl-coA and moves it into the mitochondria –Releases some CO2, fills up some electron carriers (2 NADH) –Has many names: prep step, grooming step, etc.

Step 1 – Preparation for Krebs Cycle

Step 2 Krebs cycle – Happens in mitochondrial matrix PURPOSE 1. Oxidizes pyruvate 2. Fills up e - carriers (FAD, NAD) – 2 acetyl CoA broken down to 4 CO2 –2 ATP, 2 FADH, 6 NADH made PER GLUCOSE

Krebs Cycle (Citric Acid Cycle)

Step 3 Electron Transport chain – –All the filled electron carriers (NADH, FADH2) dump their electrons here –Energy in electrons is transferred to to make 32 ATP –“dead” Electrons “caught” by O2 to make H2O

Oxidative Phosphorylation

ETC + Chemiosmosis

Steps Final Tally: Create a table in your notes packet

Respiration What do we notice about respiration in comparison to Photosynthesis?

THE BIG PICTURE

Is energy recycled? What about the reactants and products??