MCAT® ExamBiological and Biochemical Foundations of Living SystemsMedium
A patient is diagnosed with a rare genetic disorder where their cells are unable to properly degrade long-chain fatty acids, leading to their accumulation and cellular dysfunction. Analysis reveals a defect in an organelle responsible for detoxification and lipid metabolism. Which organelle is most likely affected in this patient?
- ARough Endoplasmic Reticulum
- BMitochondria
- CLysosomes
- DPeroxisomes
Show answer & explanationAnswer & explanation
Correct answer: D. Peroxisomes
Peroxisomes are responsible for the beta-oxidation of very long-chain fatty acids, detoxification of harmful substances, and synthesis of certain lipids. A defect in peroxisomes would lead to the accumulation of long-chain fatty acids.
Why the other options are wrong
- A. Rough Endoplasmic Reticulum is involved in protein synthesis and modification, not fatty acid degradation.
- B. Mitochondria are involved in cellular respiration and ATP production, and also beta-oxidation of shorter fatty acids, but peroxisomes handle very long-chain fatty acids.
- C. Lysosomes are primarily involved in the degradation of waste materials and cellular debris, not specifically long-chain fatty acid breakdown.
Peroxisome Function
Membrane-bound organelles involved in metabolic processes, including the breakdown of fatty acids (especially very long-chain fatty acids) and detoxification of harmful substances.
- Contain oxidative enzymes (e.g., catalase, oxidases).
- Perform beta-oxidation of very long-chain fatty acids.
- Detoxify hydrogen peroxide and other harmful compounds.
- Involved in lipid biosynthesis.
Memory trick: Peroxisomes are the peroxi-cleaners for fatty acids.