Lecture 5 Outline (Ch. 9) I.Respiration Overview (pp ) II.Redox Reactions III.NAD+/NADH IV.Glycolysis (pp ) V. Pyruvate Oxidation VI. Citric Acid Cycle VII. Before next class: review these slides and text, and use the boxed sets on the last slide to match into groups

Cellular Respiration Overall purpose: convert food to energy animals AND plants complementary to photosynthesis

Cellular Respiration: (Exergonic) Cellular Respiration catabolizes sugars to CO 2 requires O 2 at mitochondrion

Redox Reactions as part of chemical reaction, e- are transferred e- transfer = basis of REDOX reactions (reduction) (oxidation)

Redox Reactions follow the H, e- move with them Use “H rule” for reactions in this class Reactant with more H’s = e donor, will be oxidized Reactant with more O’s = e acceptor, will be reduced ZH 2 + O 2 yields ZO + H 2 O

Self-Check ReactionMolecule Reduced Molecule Oxidized ZH 2 + O 2 yields ZO + H 2 O CH 4 + 2O 2 yields CO 2 + 2H 2 O C 6 H 12 O 6 + O 2 yields CO 2 + H 2 O C 8 H 18 + O 2 yields CO 2 + H 2 O OxygenZH 2

transfer of e- to oxygen is stepwise Redox Reactions

Gummi bear added to potassium chlorate (KClO 3 ), a strong oxidizing agent What if the transfer of electrons was not stepwise in cells?

e- moved by NAD/H (from niacin/vit B 3 ) NADH  carry e- (reduced!) NAD+  not carrying e- (oxidized!) Redox Reactions

In this equation NAD+ is converted to NADH. NAD + + H + + 2e-  NADH a. Which is the organic compound reactant? b. Did this reactant gain or lose electrons to become the product? c. Is this reactant oxidized or reduced to make the product?

1. glycolysis Steps of respiration : 3. Citric acid cycle 4. ETC & oxidative phosphorylation Steps of Respiration 2. Pyruvate oxidation 4 CO 2 2 CO 2

1. Glycolysis 1 glucose (6C)2 pyruvate (3C) Keep track of:- inputs/outputs - Electron carriers plus: -ATP/ADP Cellular Respiration -CO 2 -O 2 eukaryotes AND prokaryotes

ATP ADP 1 Glucose Glucose-6-phosphate Glycolysis 2 Glucose-6-phosphate Fructose-6-phosphate

Fructose- 1, 6-bisphosphate Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate 4 5 Glycolysis ATP ADP

2 2 ADP 2 ATP Phosphoenolpyruvate 2 Pyruvate 10 Glycolysis 2 ATP 2 ADP 3 steps not shown 2 NADH 2 NAD+

In glycolysis….. a. Is any O 2 or CO 2 used or produced? b. How many ATP are used? How many are produced? What is the NET ATP production? c. Where do the phosphates come from to make ATP? d. What are the outputs of glycolysis and where do these molecules go?

Energy production Mitochondria energy from nutrients  ATP

2. Pyruvate Oxidation (coenzyme junction) 2 pyruvate (3C) 2 Acetyl CoA (2C) Cellular Respiration pyruvate joins coenzyme A (from vitamin B 5 ) 2 carbons lost (as CO 2 ) 2 NAD+  2 NADH Where do the outputs go?

Cellular Respiration 3. Citric acid cycle 2 Acetyl CoA (2C) join oxaloacetate (4C) few ATP so far e- to carriers (NAD+, FAD) now in matrix of mitochondrial 2 citrate (6C) converted over several steps, 4C lost (CO 2 ) 2 ATP made Where do the outputs go?

At home Match each Step Name with Energy Balance and Basic Reaction