[ M2 BIOCHEM ] Fatty Acid Synthesis, Beta Oxidation ; Mevalonate, Ketogenesis

Triacylglycerides, phospholipids

Examples of saponifiable lipids

Terpenes, sterols

Examples of non-saponifiable lipids

Cytosol

Site of fatty acid synthesis

Fatty acid synthesis

Conversion of acetyl CoA to malonyl CoA using ACC

Condensation → hydrogenation → dehydration → hydrogenation

Constant steps in fatty acids, adding 2 Carbons each step

Palmitoyl CoA

Performs negative feedback to inhibit the formation of citrate

Digested by lipase; converted to micelles by bile acids

Fates of TAGs during digesting in the git

Emulsify

Bile acids ___ TAGs for further absorption in the git

Glucagon release, insulin inhibition

Fat breakdown is triggered by fasting, with ___

Hormone sensitive lipase (HSL)

Triglycerides are initially hydrolyzed by ___ into glycerol and fatty acids

Glycerol, fatty acids

Triglycerides are hydrolyzed by hormone sensitive lipase into ___

Beta / fatty acid oxidation

Breakdown of fatty acids by 2 carbons at a time, stimulated by glucagon in the fasted state

4 ATP

In fatty acid synthesis, each cycle / 1 NADH and 1 FADH produces ___ ATP

1 Acetyl CoA

Since 2 carbons are cleaved off during fatty acid oxidation, these 2 carbons turn into ___

Mitochondrial matrix

Fatty acids are synthesized in the cytosol, but their oxidation occurs in the ___

2 ATP

Sacrificed/deducted at the start of beta oxidation; for free fatty acid to enter the mitochondrial and turn into acetyl CoA

10 ATP

Each acetyl CoA produces ___ ATP

Condensation of 3 acetyl CoA

HMG / hydroxymethyl glutaryl CoA is formed by ___

Cholesterol

HMG CoA synthesized in the cytoplasm will become ___

Ketone bodies

HMG CoA synthesized in the mitochondria will become ___

Mevalonate pathway

Pathway for cytoplasmic synthesis of sterols and terpenes

Acetyl CoA

Building blocks of the Mevalonate pathway

15 C

In the Mevalonate pathway, Farnesyl pyrophosphate has ___C

HMG CoA reductase

Rate limiting enzyme of the Mevalonate pathway; inhibited by statins

10 C

Terpenese have ___ C

Liver, kidney

Activated vitamin C (cholecalciferol) so it can be used

Calcitriol

Active form of vitamin D

Ketogenesis

Production of ketone bodies in the mitochondrion, during fasting state

Beta oxidation

Accompanies ketogenesis due to acetyl CoA overflow

HMG CoA

In TCA, 2 acetyl CoA are removed every cycle and become ___

HMG CoA lyase

Rate limiting enzyme of ketogenesis

Ketone bodies

Since the brain cannot use fats produced when we are fasting, ___ are used as the emergency fuel of brain

Urine, acetone (through lungs)

Ketone bodies can be excreted via ___

Ketosis

Shift from dependence of glucose to dependence on ketone bodies

Ketonemia

Elevated ketone bodies in blood (20mg/100 mL)

Ketonuria

Elevated ketone bodies in urine (70mg/100 mL)

Ketoacidosis

Excessively elevated ketone bodies (COO-), resulting in much lower blood pH

Glucagon

Promotes ketogenesis, during fasting state

Lipolysis, beta-oxidation, and ketogeneses increase

People with diabetes type 1 have low insulin (inhibits ketone bodies), so ___ increase