LB145Sec 001-004

Today’s Announcements• StudyNotes5 AND Homework4 are due.• Field Trip sign up!• Tutorial – Feb. 22: 3-5pm [Room C-3]• Evaluate HW 4.• Take up the HW.• Anaerobic Respiration (Fermentation)• Hitting the Wall and Feeling the Burn

Homework Problem:Question: The Glucose Problem In the molecular process known as cellular respiration, how many ATP molecules can be made from the electron transport chain after one molecule of glucose is catabolized in glycolysis, pyruvate processing and the citric acid cycle. Assume that 1 ATP is produced when 3.5 protons pass through ATP synthase.

Campbell 8e Fig. 9.16

ETC: The main pieces

Complex I: NADH dehydrogenase• removes e- from NADH• pumps 4 H+ into inter-

membrane space

Complex II: succinate dehydrogenase• moves e- from FADH2 to Q

Complex III: Cytochrome bc1

• transfers e- from Q to Cyt c• pumps 2 H+ into intermembrane space

Complex IV: cytochrome c oxidase• transfers e- from Cyt c to O2

• pumps 2H+ into intermembrane space

Q: ubiquinone, pumps 2 H+ into intermembrane space

Cyt c: cytochrome c• e- shuttles

Fermentation and Anaerobic Respiration

Fig. 9-19Glucose

Glycolysis

Pyruvate

CYTOSOL

No O2 present:Fermentation

O2 present: Aerobic cellular respiration

MITOCHONDRIONAcetyl CoAEthanol

orlactate

Citricacidcycle

ATP Production:Sprinters vs. Distance Runners

Anaerobic Fermentation – Feeling the Burn

Why would sprinting or intense exercise induce anaerobic fermentation?

Anaerobic Fermentation – Feeling the Burn

The need for ATP exceeds the uptake of oxygen.

Fig. 9-19Glucose

Glycolysis

Pyruvate

CYTOSOL

No O2 present:Fermentation

O2 present: Aerobic cellular respiration

MITOCHONDRIONAcetyl CoAEthanol

orlactate

Citricacidcycle

Marathon runners “hit the wall” when they use up all their carbs and shift to burning their fats.

Fat metabolism is slower than glucose metabolism, making ATP production, and hence running, more difficult.

Marathon Running: Hitting the Wall

Anaerobic Respiration Quiz1. Which metabolic pathway is common to both

cellular respiration and fermentation?a) chemiosmosis.b) the oxidation of pyruvate to acetyl CoA.c) the citric acid cycle.d) oxidative phosphorylation.e) the production of pyruvate

Anaerobic Respiration Quiz

2. One function of both alcohol fermentation and lactic acid fermentation is to

a) oxidize NADH to NAD+.b) reduce FADH2 to FAD+.

c) reduce FAD+ to FADH2.

d) reduce NAD+ to NADH.e) none of the above.

COMING UP:Thursday February 21st: Molecular SculptingFriday February 22nd: TutorialMonday February 25th: Open registration for Field Trip ($12)Tuesday February 26th: Review Session (DYKWYTYK)

Thursday February 28th: MIDTERM EXAM #2