Cellular Respiration

Cellular Respiration Glycolysis, Fermentation, Krebs Cycle, Electron Transport Chain California Science Standards #1f, 1g, 1i, 6d, 9a

Review • CO2 + H2O  C6H12O6 + O2 • Photosynthesis • Store Energy • C6H12O6 + O2  CO2 + H2O • Cellular respiration • Just the of photosynthesis • Release energy reverse

Cellular Respiration • An Overview (“Map”) Organic Compounds ATP Glycolysis Fermentation Aerobic Respiration ATP

Glycolysis • Breaks down glucose into pyruvic acid • STEP 1: Two P’s (from two ATPs) attach to glucose, making a new 6-C compound • STEP 2: The new 6-C compound is split into two 3-C molecules of PGAL (just like Calvin) • STEP 3: The two PGALs each receive another Phosphate group; 2 NADHs formed • STEP 4: All P’s are stripped off (eeek!), revealing 2 molecules of pyruvic acid • 4 new ATPs are made when 4 ADPs receive the P’s • Glycolysis has a net yield of 2 ATPs. How?

C C C C C C C C C C C C C C C C C C Glucose STEP 3 2 NAD+ -2 ATP 2 molecules of 3-C compound STEP 1 6-carbon compound P C C C P P C C C P STEP 4 P P STEP 2 2 molecules of pyruvic acid 2 molecules of PGAL 4 ATP P C C C C C C P

Glycolysis, Continued • Watch 

Cellular Respiration • Check the Map… Organic Compounds ATP Glycolysis Fermentation Aerobic Respiration ATP

Fermentation • No oxygen? No problem… • 2 types: lactic acid fermentation, alcoholic fermentation • Pros: can regenerate NAD+ when short on O2 • Keeps glycolysis going • Cons: Cannot produce ATP

C C C C C C C C C C C C Lactic Acid Fermentation • Manufacture of yogurt, cheese • Muscle cells • “Anaerobic exercise” (sprints) • Lactic acid build-up (muscle burn, fatigue, cramps) Glucose Glycolysis Pyruvic acid NAD+ NADH + H+ Lactic acid

C C C C C C C C C C C C C Alcoholic Fermentation • Basis of wine and beer industries • Yeast + fruit juice = alcohol • Takes place when making bread • CO2 makes bread rise; alcohol evaporates Glucose Glycolysis Pyruvic acid CO2 NAD+ NADH + H+ C Ethyl alcohol 2-C compound

Section 7-1 Review • Do page 131, #1-6

Cellular Respiration • Check the Map… Organic Compounds ATP Glycolysis Fermentation Aerobic Respiration ATP

Aerobic Respiration • Requires oxygen • Produces nearly 20x as much ATP as is produced by glycolysis alone • 2 major stages: • Krebs cycle • Electron transport chain

Krebs Cycle • 1st stage of aerobic respiration • Breaks down acetyl CoA, producing CO2, hydrogen atoms, and ATP • STEP 1: Acetyl CoA combines with oxaloacetic acid to produce citric acid • STEP 2: Citric acid releases a CO2 molecule to form a 5-C compound • STEP 3: The 5-C compound releases a CO2 molecule to form a 4-C compound • STEP 4: The 4-C compound is converted into a new 4-C compound • STEP 5: The new 4-C compound is converted back into oxaloacetic acid

CoA CoA Citric acid C Acetyl C C C C C C C C 1 2 Oxaloacetic acid 5-C compound CO CO 2 2 C C C C C C C C C C 3 5 4-C compound 4-C compound 4 C C C C C C C C NADH Krebs Cycle NADH NADH FADH2 ATP

cristae Electron Transport Chain • 2nd stage of aerobic respiration • Located on inner membrane folds (cristae) of mitochondrion

Electron transport chain is here

Electron Transport, continued • Electron transport is the “clean-up batter” • “Bats” in NADH’s and FADH2’s (“base runners”) to make mucho ATP (“runs” or RBI’s). How? • Electrons in NADH and FADH2 are “hot potatoes” • They get passed down the chain, and their “heat” helps pump protons from the matrix (inner compartment) to the outer compartment • The concentration gradient of protons drives the synthesis of ATP by chemiosmosis

2. Pump the protons 1. Pass the potato (e-)

3. Chemiosmosis

Total ATP From Cellular Respiration

Cellular Respiration