Cellular Respiration Chapter 9-1

Cellular Respiration Aerobic The process in which cells make ATP by breaking down organic compounds, like glucose in the presence of oxygen. SUNLIGHT PHOTOSYNTHESIS C6H12O6 + 6O2 6CO2 + 6H2O AEROBIC RESPIRATION

start (glycolysis) in cytoplasm A biochemical pathway in which glucose is used to produce pyruvic acid in the cytoplasm just outside the mitochondria. start (glycolysis) in cytoplasm completed in mitochondrion

- Step #1 Glucose is split into two, 3-carbon molecules of PGAL, using a couple ATP’s and NADH.

Step #2 During this step energy from PGAL is passed to an electron acceptor called NAD, forming NADH.

Step #3 More ATP’s are made.

Eventually Pyruvic acids and 2 ATP’s are produced. Step #4 Eventually Pyruvic acids and 2 ATP’s are produced.

PGAL Made at the beginning of Glycolysis and is converted into 2 molecules of Pyruvic Acid.

Products of Glycolysis Small amounts of ATP 2 molecules of Pyruvic Acid NADH ATP

Conclusion and Glycolysis Chart Location – Cytosol just outside the mitochondria Function – Breaking down glucose to Pyruvic Acid Reactants – Glucose ADP and NAD (accepts high energy electrons) Products – ATP, NADH, Pyruvic Acid.

Fermentation - Cytosol ( without oxygen) Anaerobic Respiration Process: pyruvic acid (initial reactant )produced from glycolysis is converted to other organic compounds. Fermentation does not produce ATP but does regenerate NAD+ which keeps glycolysis going.

Pathways of Fermentation Two main pathways: lactic acid fermentation and alcoholic fermentation

Lactic Acid Fermentation 1. An enzyme converts pyruvic acid into a 3-C molecule called lactic acid (stored in your muscles – Soreness) 2. During fermentation, NADH is converted into NAD. No ATP is made.

3 NAD will now recycle back to glycolysis to help break down glucose to produce pyruvic acid. 4. Regenerating NAD in fermentation ensures the cycle of glycolysis to continue operating. 5. No ATP is made in this fermentation. NADH – Made in glycolysis and broken down into NAD in fermentation.

electrons, hydrogen from NADH GLYCOLYSIS C6H12O6 2 ATP energy input 2 ADP 2 NAD+ 2 NADH 4 ATP 2 pyruvate energy output 2 ATP net LACTATE FORMATION electrons, hydrogen from NADH 2 lactate Fig. 7.9, p. 118

Alcoholic Fermentation An enzyme converts pyruvic acid into ethyl alcohol in two steps: Step -1. A CO2 molecule is removed from the pyruvic acid, leaving a 2-C molecule

Step 2: Two hydrogen atoms from NADH are added to the 2 - carbon compound to form ethyl alcohol, a. recycling NAD to return to Glycolysis.

Products Process results in the making of beer, wine, and bread.

electrons, hydrogen from NADH GLYCOLYSIS C6H12O6 2 ATP energy input 2 ADP 2 NAD+ 2 NADH 4 ATP energy output 2 pyruvate 2 ATP net ETHANOL FORMATION 2 H2O 2 CO2 2 acetaldehyde electrons, hydrogen from NADH Fig. 7.10, p. 119 2 ethanol

Conclusion and Alcoholic Fermentation and Lactic acid Chart Location – Cytosol Function – Recycle NAD for glycolysis Reactants – Pyruvic Acid and NADH Alcohol Products - – Alcohol, Carbon Dioxide, NAD Lactic acid Products – Lactic acid and NAD