20 Questions
Where does β-oxidation of fatty acids occur?
In the mitochondria
What is the role of carnitine in fatty acid metabolism?
Facilitates transfer of fatty acids into the mitochondria
Which enzyme is responsible for transferring fatty acids to carnitine in the mitochondria?
Carnitine palmitoyl transferase 1 (CPT1)
How does the carnitine shuttle operate for transporting long chain fatty acids?
By an antiport mechanism moving free carnitine and acyl carnitine derivative in opposite directions across the inner mitochondrial membrane
Where do all the synthetic reactions occur in the cell?
Cytoplasmic compartment
In which organelle are all the enzymes located?
Endoplasmic reticulum
What is the drug that inhibits HMG-CoA reductase commonly known as?
Statin
What is the main function of statins?
Lowering cholesterol levels in the blood
What is the real cause of Sudden Infant Death Syndrome (SIDS)?
Not known
What is Zellweger syndrome characterized by?
Impaired peroxisomal function
What is the primary function of the carnitine shuttle in fatty acid metabolism?
Preventing the catabolism of newly synthesized fatty acids
Which enzyme facilitates the transfer of fatty acids from the cytoplasm to the mitochondria in the carnitine shuttle?
CPT-1
Where does β-oxidation of fatty acids primarily occur?
Mitochondria
What is the main product of β-oxidation of a palmitoyl CoA molecule?
$131$ ATPs
What are ketone bodies synthesized from in the liver during fasting?
Acetyl CoA derived from fatty acid oxidation
What condition can result from the accumulation of ketone bodies in the blood and urine due to uncontrolled diabetes mellitus?
Ketoacidosis
How does the liver regulate the production and use of ketone bodies in normal conditions?
To maintain pH balance in the body
Apart from fatty acids, what other component of triglycerides can be used as an energy source?
Glycerol
What are essential fatty acids rapidly converted into?
Various bioactive compounds like prostaglandins, prostacyclin, and thromboxane
Where is most cholesterol found in the body?
In free form and readily absorbable from diet or produced endogenously by the liver and intestinal mucosa.
Study Notes
- The carnitine shuttle is a process that prevents the catabolism of newly synthesized fatty acids after carbohydrate-rich meals, favoring their export from the liver for storage in adipose tissue.
- The shuttling process involves the transfer of fatty acids from the cytoplasm to the mitochondria, which is facilitated by carnitine and the enzyme CPT-1.
- The process of β-oxidation of fatty acids occurs in the mitochondria and consists of four basic reactions: dehydrogenation, hydration, dehydrogenation, and cleavage.
- β-oxidation yields a significant amount of energy, with the oxidation of a palmitoyl CoA molecule producing 131 ATPs.
- Ketone bodies are synthesized by the liver from acetyl CoA derived from fatty acid oxidation. They are important sources of energy for peripheral tissues during fasting.
- Uncontrolled diabetes mellitus can lead to the accumulation of ketone bodies in the blood and urine, resulting in a condition called ketoacidosis, which can cause severe acidosis and other complications.
- In normal conditions, the liver regulates the production and use of ketone bodies to maintain the pH balance in the body.
- Glycerol, a component of triglycerides, can also be used as an energy source via glycolysis and the citric acid cycle.
- Essential fatty acids, such as Arachidonic Acid, are rapidly converted into various bioactive compounds like prostaglandins, prostacyclin, and thromboxane, which control various physiological processes.
- Most cholesterol is in free form and can be absorbed readily from diet, while the body also produces cholesterol endogenously, primarily by the liver and intestinal mucosa.
Test your understanding of lipid metabolism lecture learning objectives. This quiz covers topics such as the role of lipids in metabolism, lipogenesis, and β-oxidation pathways.
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