TwoOldGuys™ Study Guides
BI-122 Biology
Metabolism
Cell Respiration
Overview
- Sugar (glucose) plus Oxygen burn to Carbon dioxide plus Water
and 720 kcal [686 kcal under standard lab conditins]
- captured as 30 ATP [theoretically 36] @ 7.3 kcal = 219 kcal captured
- 720 - 219 = 501 kcal lost as waste heat
- 219/720 = 30.4% efficiency [theoretical 36*7.3/686 = 40%]
| |
| Cell Respiration [oxidation] |
| reactants |
|
products |
| |
|
|
|
|
|
| oxidation of C |
|
|
|
| C6H12O6 |
+ |
6 O2 |
→ |
6 CO2 |
+ |
6 H2O |
+ |
+ 686 kcal |
| |
|
reduction of O |
|
↓ |
| |
|
| energy capture reaction |
| |
|
|
|
36 ADP |
+ |
36 Pi |
+ |
- 263 kcal |
→ |
36 ATP |
| |
|
|
|
|
|
|
|
- 423 kcal |
→ |
waste heat |
| |
Metabolic pathways
- glycolysis
- citric acid cycle (Krebs cycle) in presence of Oxygen
- fermentation in the absence of Oxygen
- electron transport system
ATP
the energy 'currency' of cells
- 1-adenine, 5-phospho-ribose = adenosine monophosphate [AMP]
- adding phosphates:
- 1-adenine, 5-diphospho-ribose = adenine diphosphate [ADP]
- 1-adenine, 5-triphospho-ribose = adenine triphosphate [ATP]
- adenine-ribose-PO4-PO4-PO4
- the ADP-P bond stores 7.3 kcal/mole
- mole of ATP = 486 g
- conceptual model:
- the ADP - ATP system is equivalent to rechargable batteries
- ADP is the discharged state of the battery
- ATP is the charged state of the battery
- the 'battery' is either fully charged [7.3 kcal/mole] or fully discharged [0.0 cal]
glycolysis
in the cytoplasm, outside of mitachondrion
- glucose
. . . . ATP → ADP
- glucose 6-phosphate
- fructose 6-phosphate
. . . . ATP → ADP
- fructose 1,6-biphosphate
- 2 glyceraldehyde 3-phosphate [PGAL]+ 2 phosphate
. . . . 2 NAD+ → 2 NADH
- 2 1,3-biphosphoglycerate [PGAP]
. . . . 2 ADP → 2 ATP
- 2 3-phosphoglycerate [PGA]
. . . . + H2O
- 2 phosphoenolpyruvate [PEP]
. . . . 2 ADP → 2 ATP
- 2 pyruvate
All known organisms which utilize sugar as a energy source use glycolysis
citric acid cycle
inside the mitachondrion
- pyruvate + CoA
- acetyl-CoA
- acetyl-CoA + oxaloacetate
- citrate
. . . . NAD+ → NADH
. . . . + CO2
- ketoglutarate
. . . . NAD+ → NADH
. . . . + CO2
. . . . ADP → ATP
- succinate
. . . . FAD → FADH2
- fumarate
. . . . NAD+ → NADH
- oxaloacetate
All known organisms which process energy aerobically use citric acid cycle
electron transport system
in cristae of mitachondrion
- NADH
- NADH reductase
. . . . 2 ADP → 2 ATP
- coenzyme Q
- cytochrome b
. . . . 2 ADP → 2 ATP
- cytochrome c
- cytochrome oxidase
. . . . 2 ADP → 2 ATP
- water
All known organisms use this electron transport system
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© 2004-2005 TwoOldGuys ™
revised 19 aug 2006