Download Stage 4 Digestion: Electron Transport Chain

Stage 4 Digestion: Electron Transport Chain - ETC
Interconnected proteins - named by Roman numerals (on
large graphic on back of page) - embedded in the inner
mitochondrial membrane
ETC Jobs
1. Dehydrogenases:
Removal of H from NADH and FADH
Separation into a high energy electron e- & H+
2. Proton pumps:
Energy of e- pump H+ into intermembrane space creating a Hydrogen ion gradient: Chemiosmosis
• creates a 100 xH+ concentration difference over inner mitochondrial membrane
3. Low energy e- is unloaded onto oxygen which reacts with H+ to form water (See equation)
½ O2 + 2e- + 2H+
H2O
Oxygen is the final electron acceptor of aerobic cellular respiration – this is why you breathe air!
Stage 5 Digestion: ATP Synthesis
ATP Synthesis
• Harvesting energy of the H+ gradient
• Works like a water wheel
ATP Synthase Enzyme
• Located in the inner mitochondrial
membrane
• allows H+ gradient to rush through using
energy to make ATP
ADP + P
ATP
ATP Conversions
• 1 cytosolic NADH = 2 ATP
• 1 mitochondrial NADH = 3 ATP
• 1 mitochondrial FADH = 2 ATP
Net ATP from 1 Glucose
• 2 ATP (G)
• 2 NADH2 (G) = 2 FADH2 (transport)
• 2NADH2 (K prep)
• 2 x 3 NADH2 (K)
• 2 x FADH2 (K)
• 2 x 1 GTP
(K)
Total ATP
2
4
6
18
4
2__
36
Location?
In which cellular compartment does each of the following take place?
a. Glycolysis
b. Citric Acid Cycle
c. Electron Transport Chain
d. Hydrogen Ion gradient
e. ATP synthase
Lipid metabolism
• Cytoplasm: lipase separates Glycerol and Fatty Acids
• Glycerol (C3) is converted to Pyruvate (C3): yields NADH
• Fatty Acids are transported into Mitochondria for β-Oxidation
• Chopped into 2 carbon molecules to make Acetyl-CoA
• Yield 1 NADH, 1 FADH/chop
Amino Acids
Liver: Removal of amino group as NH3 (ammonia)
Ammonia is toxic, reacts with CO2 to form urea, secreted as liquid waste: kidneys
O
NH3 + CO2
Ammonia
NH2-C-NH2
urea
Carbon skeleton of AA
• AA skeletons with 2 C → Acetyl
• AA skeletons with 3 C →Pyruvate
• AA skeletons with 4 C → Succinate fumarate, malate, oxaloacetate
• AA skeletons with 5 C→ α-Ketoglutarate