Insulin and Fatty Acid Metabolism

<p>Activating inactive acetyl CoA carboxylase (C)</p> Signup and view all the answers

<p>It inhibits adenyl cyclase activity (C)</p> Signup and view all the answers

<p>They bind to albumin in the plasma before entering. (D)</p> Signup and view all the answers

<p>It binds free fatty acids in the plasma for transport. (C)</p> Signup and view all the answers

<p>Fatty acids can remain bound to albumin once inside the cell. (A)</p> Signup and view all the answers

<p>Albumin (B)</p> Signup and view all the answers

<p>They pass through the adipocyte membrane. (C)</p> Signup and view all the answers

<p>It transports acyl-carnitine into the mitochondrion. (B)</p> Signup and view all the answers

<p>Carnitine palmitoyl transferase (CPT-II) (D)</p> Signup and view all the answers

<p>It prevents acyl groups from entering the mitochondrial matrix. (D)</p> Signup and view all the answers

<p>It prevents acyl groups from being oxidized. (C)</p> Signup and view all the answers

<p>Malonyl CoA (A)</p> Signup and view all the answers

<p>Glucose (C)</p> Signup and view all the answers

<p>Fatty acids do not cross the blood-brain barrier efficiently (D)</p> Signup and view all the answers

<p>They lack mitochondria (B)</p> Signup and view all the answers

<p>Fatty acids (A)</p> Signup and view all the answers

<p>It continues to rely on glucose (C)</p> Signup and view all the answers

<p>31 ATP (B)</p> Signup and view all the answers

<p>Triacylglycerol is converted to diacylglycerol and then to monoacylglycerol (C)</p> Signup and view all the answers

<p>It converts fatty acids into acyl CoA in the cytoplasm (D)</p> Signup and view all the answers

<p>12 ATP (A)</p> Signup and view all the answers

<p>It activates adenylate cyclase (C)</p> Signup and view all the answers

<p>Acetyl CoA, FADH2, and NADH (A)</p> Signup and view all the answers

<p>To dehydrogenate acyl CoA at specific carbon positions (A)</p> Signup and view all the answers

<p>Four reactions (D)</p> Signup and view all the answers

<p>One acetyl group, one FADH2, and one NADH (A)</p> Signup and view all the answers

<p>Fatty Acyl CoA (C)</p> Signup and view all the answers

Insulin activates the production of fatty acids (FAs) by converting inactive acetyl CoA carboxylase into its active form.

Insulin inhibits the breakdown of fats by deactivating adenylate cyclase. This, in turn, inactivates protein kinase, which ultimately deactivates hormone-sensitive lipase (HSL).

Glycerol, a byproduct of fat breakdown, is transported through the bloodstream to the liver.

In the liver, glycerol is phosphorylated, meaning a phosphate group is added.

Phosphorylated glycerol can be used in various metabolic pathways, including glucose synthesis (gluconeogenesis).

A protein found in the blood that helps transport free fatty acids.

Movement of free fatty acids across the cell membrane of an adipocyte.

A type of cell that stores fat tissue.

Unbound fatty acids that are not attached to other molecules.

The liquid portion of blood.

Acyl-carnitine is transported into the mitochondrion in exchange for free carnitine. This process is facilitated by a membrane protein called carnitine translocase.

Once inside the mitochondrion, acyl-carnitine is converted back to acyl CoA, releasing carnitine.

Carnitine palmitoyl transferase II (CPT-II) is an enzyme that catalyzes this conversion.

Malonyl CoA, a key intermediate in fatty acid synthesis, inhibits the first step of fatty acid breakdown, preventing further entry of acyl groups into the mitochondria.

By stopping the entry of fatty acids into the mitochondria, malonyl CoA inhibits the process of beta-oxidation.

Erythrocytes, or red blood cells, lack mitochondria, the organelles responsible for fatty acid metabolism. This means they can't use fatty acids as an energy source.

The blood-brain barrier, a protective layer surrounding the brain, restricts the passage of fatty acids. This means the brain relies primarily on glucose for energy during fasting.

During periods of fasting, both erythrocytes (red blood cells) and the brain continue to rely on glucose for energy, even though other tissues can utilize fatty acids.

Erythrocytes can't use fatty acids because they lack mitochondria, the organelle responsible for fatty acid breakdown.

The blood-brain barrier, a protective layer around the brain, blocks the entry of many substances, including fatty acids. This makes glucose the primary energy source for the brain.

A process where fatty acids are broken down into acetyl-CoA, generating energy in the form of ATP. It occurs in the mitochondria of cells.

The complete breakdown of one molecule of palmitic acid (C16 fatty acid) yields around 131 ATP molecules.

An enzyme that catalyzes the conversion of fatty acids into acyl-CoA, a form that can be used for energy production.

Acyl-CoA is a fatty acid molecule attached to coenzyme A, making it a key intermediate in the breakdown of fatty acids for energy production.

Acyl CoA dehydrogenase removes two hydrogen atoms from the acyl CoA molecule, creating a double bond between the second and third carbon atoms (C-2 and C-3).

The product of the reaction catalyzed by acyl CoA dehydrogenase is enoyl CoA. It contains a double bond between the second and third carbon atoms.

Beta-oxidation is a cyclical process that breaks down fatty acids into acetyl CoA molecules, which are then used in the citric acid cycle for energy production.

The complete breakdown of a saturated fatty acid with an even number of carbon atoms yields acetyl CoA, NADH, and FADH2. These molecules are further utilized in the citric acid cycle and electron transport chain for energy production.

Each cycle of beta-oxidation removes a two-carbon unit from the fatty acid, generating one molecule of acetyl CoA, one NADH, and one FADH2. This process repeats until the entire fatty acid chain is broken down.