Biochem Test 5

• 1. Energy density is high.
• 2. They are insoluble so they don't impact osmolality.
• 3. They are hydrophobic, so they won't suck up water like glycogen will.

• 1. Ingested fats
• 2. Stored fats
• 3. Produced fats, this occurs in the liver.

Amphipathic cholesterol derivitives that help maximize the digestible surface area of triacylglycerols.

Lipases cleave triacylglycerols into glycerol and 3 fatty acids.

• a. Bile Salts
• b. Pancreatic Lipase
• c. Tryacylglycerol

• Glycerol ~ 5% total calories.
• 3 fatty acids ~ 95% total calories.

• It is phophorylated and dehydrogenated into GAP in steps 5/6 of glycolysis.
• It goes on to produce 2 ATP and 1 Pyruvate.

Cholesterol, Apolipoprotieins, and phospholipids forma shell around triacylglycerols and cholesteryl esters.

They are absorbed by the intestinal mucosa, and it is there that they are assembled into chylomicrons.

• 1. Hormone (Glucogon, Epinephrine) binds to receptor, active g-protine, Activates Adenylyl Cyclase.
• 2. Active AC pumps out cAMP, which activates protein Kinase A (PKA)

• 3,4. PKA phosphorylates A. Hormone Sensitive Lipase (HSL). B. Perilipin membrane border.
• The phosphorylated perilipin is destabilized, and HSL can move from out to in and begin breaking down the TAG lipid droplet.

• 5. TAG is metablolized by P(HSL) and is moves to the cytosol as individual Fatty acids.
• 6. The FA's are moved to the blood stream where they are picked up and transported by Serum Albumin

• 7. At a myocyte Serum Albumin releases the FA, which is brought into the cell by a FA transporter.
• 8. It then undergoes B-oxidation, TCA, and respritory chain to produce ATP and CO₂

In the cytosol they are converted to fatty acyl-CoA

• The Carboxylate head of the Fatty acid is phosphorylated by ATP at P₁ not P₃ as usual. The resulting PP is immediately reduced into inorganic phosphate.
• 
• This is done by fatty acyl-CoA synthetase.

• The Thiol group of CoA attacks the carbon. The e^- jump up the C=O and then back down. Because of previous phosphorylation, the O-P is now strong leaving group.
• 
• This is also done by fatty acyl-CoA synthetase

In the mitochondrial matrix

• Carnitine is the transporter "handle" that replaces S-CoA so that the FA can be transported past the 2 mitochondrial membranes into the mitochondrial matrix.
• It is pumped back out of the mitochondria after it is released from the FA.

• Carnitine acyltransferase 1 & 2.
• You should note that the Data suggests a tetrahedral intermediate.

R-CH₂-CH₂-CH₂-CO-S-CoA

• 1 NADH = 2.5 ATP
• 1 FADH₂ = 1.5 ATP
• 1 Acetyl CoA

• Acyl-CoA dehydrogenase.
• *

• Enoyl-CoA Hydratase
• Addition of water accross double bond.
• *

• Beta-Hydroxyacyl-CoA Dehydrogenase
• Forms the trans configuration
• *

• Acyl-CoA Acetyltransferase.
• Pops up, down, and off x2
• Cuts between Alpha and Beta and preps for repeat of 1-4.
• *

*

• The enzymes pause FAO until the double bond is isomerized to the alpha-beta (2,3) trans form.
• Then it will procede.
• This is the principle for both monounsaturated and polyunsaturated fatty acids.

• They procede like normal until the final propionyl-CoA (3C-SCoA) is reached.
• *

The enzymes required for the actions are contained inside the membranes.

• They are pigments.
• They have long hydrocarbon tails, so they are integrated into the membrane.
• They are constructed similar to heme, but with Mg in the center instead of Fe.

• a: 660, 415
• b: 460, 640

• An electron pair starts off in the HOMO. the EM radiation enters and and kicks 1 electron up to the LUMO.
• The Electron that is kicked up, and the hole it left behind constitute the Exciton.
• The Electron has a negative charge, the hole has a positive charge, so the net is neutral.

• The array of pigments create and transfer excitons down to the center, aka reaction center.
• The photochemical reaction center converts the energy it receives from the exciton into a separation of charge. This initiates an electron flow.

• An exciton arrives from an antenna molecule and excites the middle electron to it's lumo.
• The LUMO is energetically equivalent to the next energy levels HOMO, so the electron shares that position.
• The lowest energy level electron donates an electron and fills the electron hole, that the 1st electron left behind.
• This results in a Net negative charge on top and a net positive charge at the bottom.

• Photosystem 2 kicks up an electron, and as it falls it pumps 2 H+ into the thylakoid space.
• Photosystem 1 then takes the electron back up, and as it falls, it eventually reduces NAD+ to NADH.

pheophytin-quinone.

Complex 3.

In the absence of NADH, the Electron will continue through PS1, through FN-oxoreductase, and create the final NADH.

In excess NADH, The electron pass through PS1 to FD. Then it will cycle back to cytochrome b6f complex and pump in an extra 2 H+ into the thylakoid space.