Steps of aerobic metabolism in animals (4)
1) Glycolysis (cytosol, anaerobic)
2) Oxidation of Pyruvate (mitochondrial matrix, aerobic)
3) Krebs Cycle (mitochondrial matrix, aerobic)
4) Electron Transport Chain (inner mitochondrial membrane (aerobic)
2 NADH, 2 ATP + (3 ATP in Eukaryotes or 5 ATP in Prokaryotes)
Net production in glycolysis.
acetyl CoA and 2 NADH
Net production of Pyruvate Dehydrogenase Complex
6NADH, 2 FADH2, 2 GTP, 2 CO2
Net production of Krebs Cycle from 1 glucose
30 ATP in Eukaryotes and 32 in Prokaryotes
Total ATP production for eukaryotes versus prokaryotes?
2.5 ATP per NADH, except for glycerol phosphate shuttle.
ATP per NADH
Glycerol Phosphate Shuttle
delivers 2 NADH from glycolysis to the mitochondria in eukaryotes. e- from NADH are passed onto coenzyme Q instead of NADH dehydrogenase. This results in 1.5 ATP per NADH instead of 2.5. NOTE: This is the reason prokaryotes have greater total ATP production
1.5 ATP per FADH2
ATP per FADH2
enzyme that catalyzes first step of glycolysis. It phosphorylates (using ATP) glucose to G-6-P
catalzyes phosphorylation of F-6-P to F-1,6-P, which is thermodynamically unfavorable. This makes it the committed step in glycolysis. It is allosterically inhibited by ATP.
*net ATP and NADH
First step of aerobic/ anaerobic respiration
Glucose + 2ADP + 2Pi + 2NAD+ ---> 2Pyruvate + 2ATP + 2NADH + 2H+ + 2H2O
Net ATP: -2ATP, +4ATP
Net NADH: +2NADH (3ATP)
- Substrate level phosphorylation:
6C glucose--> 6C fructose--> 2x 3c pyruvate
Anaerobic conditions w/o O_2, and thus no ETC. Build up of NADH uses pyruvate as the terminal e- acceptor, generating either ethanol or lactate
Key is that it allows glycolysis to continue
Products of Fermentation
Lactic Acid (muscle)
Problems: End products are toxic, nets only 2ATP/ glucose
2ATP: The net per-glucose energy yield of anaerobic metabolism in animals (glycolysis + lactic acid fermentation).
Pyruvate oxidation/ decarboxylation (2)
*net ATP and NADH
Net ATP: 0
Net NADH: 2 (5ATP)
Net CO2: 2
3C pyruvate--> 2C acetyl +CoA--> Acetyl CoA
after transportation of pyruvate from cytoplasm to mitochondrial matrix, this process (pyruvate dehydrogenase complex) converts pyruvate to acetyl-CoA
AMP and ADP cause increase rate of pyruvate conversion to acetyl CoA. Conversion is catalyzed by pyruvate dehydrogenase
Regulation of PDC
necessary for enzyme fxn, but are non-protein organic molecules that are added after translation
NOTE: vitamins are examples
Krebs Cycle (3)
group of rxns which take 2 carbon molecule, Ace-CoA, add OAA, and release CO_2. OAA is regenerated where enzymes are located in the matrix
Net ATP: 0
Net GTP: 2
Net NADH: 6 (15ATP)
Net FADH2: 2 (3ATP)
decarboxylation in Kreb's cycle
molecule that is oxidize to release CO2 is part of what process?
Electron transport chain (4)
Enzymes located in the inner mitochondrial membrane (EUK) or plasma membrane (PRO). Enzymes are NADH Dehydrogenase, Coenzyme Q, Cytochrome C reductase, Cytochrome C, and Cytochrome Oxidase. I, III, and V all pump out H+
Oxidative phosphorylation occurs at the inner mitochondrial membrane during the electron transport stage of cellular respiration
- NADH donates H+ to first protein, H+ collects in lumen, e- passes down proteins. FADH2 donates H+ to second smaller protein, H+ collects in lumen, e- passes down proteins
- Final electron acceptor is Oxygen--> H2O
- A proton gradient forms due to ETC across the inner mitochondrial membrane. ATP synthase allows protons to move down concentration gradient and turn ADP-->ATP
Glucose con is low and glycogen is depleted, then liver converts noncarbs to OAA and then to glucose
fatty acids breakdown in mitochondria of hepatocytes, removing 2-carbons at a time and converting them to Acetyl-CoA, generating 1 NADH and 1 FADH_2 per 2 carbons removed
free amino acid converted to urea and remainder is broken down to water and CO_2.
The steps of anaerobic metabolism (2)
- Glycolysis Alcohol Fermentation
- Lactic Acid Fermentation
How do ATP, NAD+, NADP+, and FAD store energy? How are they all equivalent to ATP?
ATP stores energy in its high-energy phosphate bonds. NAD+, NADP+, and FAD store energy in high-potential electrons
NADH= 2.5 ATP
NADH from glycolysis=1.5ATP (electron to second protein)
NADH, NADPH, FADH₂ are all oxidizing or reducing agents?
Is FAD and NAD+ reduced or oxidized during catabolic processes? during anabolic processes?
Anabolic v. catabolic
1. An anabolic process is a reaction that builds complex molecules and requires energy
2. A catabolic process is a reaction that breaks down complex molecules and releases energy
Autotroph v. Heterotroph
1. An autotroph is an organism that can harness sunlight to create energy via photosynthesis
2. A heterotroph is an organism that breaks down organic nutrients for energy
How is aerobic respiration different for Eukaryotes v. Prokaryotes?
Prokaryotes' respiration all occurs in the cytosol. They therefore realize 100% of the glycolytic NADH and have 2 more ATP/ glucose than Eukaryotes.