9-2 The Krebs Cycle & Electron Transport (Interactive pgs ) AFTER GLYCOLYSIS... 90% of the energy from glucose is still unused It is locked in pyruvic acid and h.e.electrons The remainder of the process requires O 2 ….therefor they following pathways are AEROBIC *9 Slides: 6 to copy

The Krebs Cycle Pyruvic acid is broken down into CO2 during a series of energy gaining reactions  A. Pyruvic acid enters the mitochondrion Carbon removed forming CO 2 Electrons removed: NAD + → NADH Acetyl-CoA is used to make citric acid  B. Energy is extracted (each pyruvic acid) Citric Acid is broken down to make 2 more CO 2 Electrons released: making 4NADH &1FADH 2 1 ATP is made

Kreb's Cycle Products (what happens to them?) CO 2 is released as you exhale. ATP is used in cellular activities NADH and FADH 2 (electron carriers) in the presence of Oxygen now move to the Electron Transport Chain to produce large amounts of ATP

Electron Transport Chain Uses high energy electrons from the Krebs cycle to change ADP into ATP Steps  A. Electron Transport Along the inner membrane of mitochondrion NADH passes the electrons from one protein carrier to the next The electrons combine with H and O to make H 2 O  B. Hydrogen Ion Movement H+ moves inside the membrane Makes the outside negative  C. ATP production H+ moves out through ATP synthase Changes ADP to ATP

The Totals Glycolysis- 2 ATPs Krebs and ETC (with Oxygen)- 36 ATPs But...I don't eat glucose? NO...but complex carbs get broken down into simple sugars like glucose. How Efficient is Cellular respiration? About 38% of the energy stored in glucose gets used in ATP the rest is lost as heat.

Energy and Exercise Quick Energy (ATP)  Small amount is stored in muscle cells  The rest is made by lactic acid fermentation Long-Term Energy  Cellular Respiration releases energy slowly  You need to train your body for long term exercise  Glycogen is the storage molecule for energy in your muscle (lasts about 20 min) After your body breaks down fat