Cellular Respiration WE NEED ENERGY!

What is it? Process where the mitochondria breaks down food molecule to produce ATP

Cellular Respiration Aerobic RespirationAnaerobic Respiration Requires oxygen to occur Occurs in the absence of oxygen Alcohol Fermentation Lactic Acid Fermentation 3 Steps: - Glycolysis - Krebs - ETC

The Phases of Respiration We will talk about each 1 in detail… Glycolysis Formation of Acetyl-CoA Citric Acid Cycle (AKA Krebs Cycle) Electron Transport Chain

Glycolysis Series of chemical reactions in the cytoplasm that break down glucose into 2 molecules of pyruvic acid In order for glycolysis to occur  requires 2 ATPs The end result  4 ATPS are produced NOT A VERY EFFECTIVE PROCESS! NAD+ (electron carrier) accepts 2 electrons to form 2 NADH + 2H+ The products: 2 molecules of pyruvic acid 2 NADH 2 ATPs (WHY?)

Formation of Acetyl-CoA This is an intermediate step Following glycolysis, pyruvic acid is transported to the mitochondria and undergoes a series of reactions The Results of these reactions: Pyruvic acid (3 carbons) is split apart  gives off CO2. Remaining 2 carbon molecule combines with Coenzyme A to produce Acetyl-CoA Produces another molecule of NADH and H+

Citric Acid Cycle Also called the Krebs Cycles Series of chemical reactions (similar to the Calvin Cycle). The molecule used in the first reaction is also the end product The products for every turn (must turn 2 times): 1 ATP x 2 = 2ATPs 2 CO2 x 2 = 4 CO 2 3 NADH + 3H+ x 2 = 6NADH + 6H+ 1FADH 2 x 2 = 2FADH 2

Electron Transport Chain Occurs in the inner membrane of the mitochondria

Electron Transport Chain Final electron acceptor = OXYGEN Reacts with 4 H+ ions and 4 electrons to produce 2 H 2 O Without oxygen, the proteins in the transport chain cannot pass electrons The Products: 32 ATP 2 H 2 O

Aerobic Respiration Products Carbon Dioxide Water 36 ATPs

Anaerobic Respiration Recall: occurs without oxygen Also referred to as fermentation There are certain instances (ie: during heavy exercise), when your cells are without oxygen for short periods of time Fermentation follows glycolysis to produce ATP until oxygen is available again

Lactic Acid Fermentation Supplies energy while oxygen is scarce 2 molecules of pyruvic acid produced in glycolysis use NADH to form 2 molecules of lactic acid Lactic acid is transferred to the muscles Builds up as your muscles fatigue Recall 2 molecules of ATP are produced during glycolysis. As a result, lactic acid fermentation also produces 2 ATPs!

Lactic Acid Fermentation

Alcohol Fermentation Used by yeast cells and some bacteria to produce CO 2 and ethyl alcohol Often occurs during baking: Bread making: yeast cells produce CO2 bubbles in the dough as it bakes The bubble pockets are left to lighten the bread

Alcohol Fermentation