ATP synthesis Flashcards
Three conformations of beta subunits
- Beta ATP-binds ATP (tightly bound)
- Beta ADP-binds ADP and Pi (loosely bound)
- Beta empty-low affinity for ATP (very loosely bound)
* you will never have two beta units in the same conformation at the same time*
Do alpha and beta subunits rotate?
No; they make conformational changes as the gamma subunit rotates
Malate-aspartate shuttle
2.5 ATP/NADH
transports to liver, kidney, and heart
Glycerol-3-phosphate shuttle
1.5 ATP/NADH
transports to brain and skeletal muscle
Adenine Nucleotide and Phosphate translocases
membrane transporter that moved charged ATP, ADP, and Pi molecules across the mitochondrial membrane
How many protons are pumped out of the matrix through the electron transport chain? How many re-enter through ATP synthesis?
Through Complex I: 10
Through Complex II: 6
Re-enter: 4 (3 used by beta subunits, 1 used by a phosphate translocase)
1 NADH= ? ATP
2.5 ATP
1 FADH2= ? ATP
1.5
Agents that interfere with oxidative phosphorylation
Rotenone Amytal: prevents electron transport from Complex I to
Ubiquinone
CN- and CO: inhibits cyt oxidase of Complex IV
Thermogenin
Uncoupling protein used to produce heat instead of ATP in brown fat. Protons bypass the ATP synthase protein using the uncoupling protein and release the energy as heat
4 lipid classes
- triacylglycerols
- cholesterols
- phospholipids
- fatty acids
Alpha Carbon in a fatty acid
Carbon next to the carboxylic acid carbon
Energy per 1g of fatty acid
37 kJ/g
~100 ATP
Lipases
Cleave ester bonds in triacylglycerol to produce a glycerol backbone and 3 fatty acid components
Pancreatic lipase
Only releases two fatty acids from a triacylglycerol
Lipolysis
Breakdown of triacylglycerol in lipoproteins
Lipoprotein Lipase and Hormone-Sensitive Lipase
Cleave all three fatty acids
What happens to fatty acid components of a triacylglycerol? The glycerol backbone?
Fatty Acids: oxidized for energy (occurs in mitochondria)
Glycerol: converted to glucose
Two requirements for fatty acids to be oxidized
- Activated (bound to CoA; outer mitochondrial membrane)
2. Transported (carnitine shuttle; inner mitochondrial membrane)
What stops the activation of fatty acid from being a reversible reaction?
The use of pyrophosphatase that converts pyrophosphate to two inorganic phosphates
Rate limiting step of fatty acid oxidation
fatty acid transport into the mitochondrion
3 Steps to produce ATP from fatty acids
- beta oxidation- degradation of fatty acids (acyl CoA), 2 carbons at a time, to produce acetyl CoA
- Acetyl CoA from beta oxidation are oxidized to carbon dioxide (TCA cycle)
- Production of ATP (oxidative phosphorylation)
4 steps of beta oxidation
- oxidation (acyl CoA dehydrogenase: introduces trans double bond, uses FAD+)
- hydration (Enoyl CoA hydratase)
- oxidation (beta dehydroxyacyl-CoA dehydrogenase, uses NAD+)
- cleavage (thiolase: cleaves thioester bond)
How many cycles are involved in the oxidation of palmatic acid?
What are the molecules produced?
How many ATP are produced?
7 cycles
Produces: 8 acetyl CoA, 7 FADH2, 7 NADH, 7 H+
Net production of 106 ATP
