1. Chapter 6: How Cells Harvest Chemical Energy

2. Muscle Fibers Fast-twitch Slow-twitch Performs best for sprints
Contract quickly but tire quickly
Make ATP anaerobically (not using oxygen
Perform best for endurance
Can sustain repeated contractions
Make ATP aerobically (using oxygen)

5. Photosynthesis vs. Cell Respiration
Photosynthesis uses carbon dioxide to produce high energy carbon molecules and oxygen
Cellular respiration uses carbon molecules and oxygen to produce energy and carbon dioxide
The products of photosynthesis are the reactants of cellular respiration

6. Cellular respiration
Function: generate ATP to be used for cellular functions
Can produce up to 38 ATP molecules which is 40% of energy from a glucose molecule, the rest is lost in heat energy

7. Energy consumption of the body
The human brain burn about 120 g (1/4 lb.) of glucose per day and uses 15% of oxygen consumption a day
The average human needs to take in 2200 kcal per day about 1.25 lb. of glucose per day

8. Reduction vs. oxidation
Reduction reactions
The addition of electrons from a substance
Oxidation reactions
The loss of electrons from a substance

9. 2 key players in oxidizing glucose
Dehydrogenase: an enzyme that takes hydrogens from molecules
NAD+ : Nicotinamide adenine dinucleotide, an organic molecule that cells make from the vitamin niacin and use to shuttle electrons in redox reactions

10. Stages of cellular respiration
Stage 1: Glycolysis: cytoplasm: breaks glucose into 2 pyruvates
Stage 2: Citric Acid Cycle: Mitochondria: Stroma: makes small amounts of ATP and provides ETS with electrons
Stage 3: oxidative phosphorylation (ETS and chemiosmosis: cristae: makes most ATP

11. Overview of cell respiration

12. Glycolysis Begins with glucose and ends with 2 pyruvates
Substrate-level phosphorylation: an enzyme transfers a phosphate group from a molecule directly to an ADP to form ATP. This is used in both glycolysis and citric acid cycle to produce small amounts of ATP
At the end the molecules of pyruvate still hold most of the energy from glucose and will be oxidized in the citric acid cycle
The 2 molecules of ATP produced here are only 5% of the glucose molecule

13. Glycolysis

14. Pyruvate for the citric acid cycle
Pyruvate loses the carboxyl group in the for of carbon dioxide (released during respiration)
2 C-compound is oxidized and NAD+ becomes NADH
Coenzyme A joins the 2 C-compound and becomes Acetyl coenzyme A

15. Citric Acid Cycle AKA the Kreb’s Cycle named for Hans Krebs
Takes place in the matrix of the mitochondria
Starts with acetyl Coenzyme A and ends with 2 CO2, 6 NADH and 2 FADH2

16. Citric Acid Cycle

17. Oxidative Phosphorylation
Includes the electron transport chain and chemiosmosis
Takes place in the cristae (folds in the inner membrane of the mitochondria). The cristae increase the surface area of the membrane so that more reactions can take place
Exergonic reaction
Chemiosmosis the energy of H+ drives the synthesis of ATP

18. Poisons that interrupt Cell Respiration
Rotenone: binds with an electron carrier at the first protein complex and blocks the movement of electrons through the ETS
Cyanide and carbon monoxide: bind with an electron carrier at the 4th protein complex blocking the passage of oxygen ceasing the flow of H so no ATP can be formed
Oligomycin (an antibiotic): used for fungal infections: prevents the flow of H

19. More poisons Uncouplers: causes the mitochondria to leak H
DNP (DiNitrophenol): produces an enomrous increase in metabolic rate, profuse sweating as the body tries to cope with the excess heat energy produced, collapse and death

20. Totals Stage where Start With ATP Dir. ATP Indir. FADH2 NADH CO2 Other
glycolysis
Cyto-plasm
Glucose
2 ATP 2
2 pyruvates
Pyruvate to Citric Acid Cycle
Cyto to mito.
pyruvate
2 (goes to the atm.
None
Citric Acid Cycle (goes through 2x)
Matrix of mito.
Acetyl CoA 6
4 (goes to the atm.)
none
Oxidative Phosphorylation
cristae
NADH, FADH2 O2
2x2=4
3X10= 30
Total 38 4 34

21. Totals

22. Lactic Acid Fermentation
Can be used by muscle cells to generate NAD+
Lactate builds up in muscles during strenuous activity, carried back to the liver and converted to pyruvate
Used in the dairy industry to make cheese

23. Alcoholic fermentation
Used in the winemaking industry

24. Anaerobes obligate aerobes: must have oxygen to survive
Obligate anaerobes: must have no oxygen to survive
Facultative anaerobe: can survive with or without oxygen

25. Organic molecules into cell respiration