Questions and Answers
What is required for ADP/ATP translocation across the inner mitochondrial membrane?
What type of cofactor does complex I contain?
Which complex is inhibited by cyanide ion (CN−)?
What is a requirement for electron transport to occur in the mitochondrial matrix?
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How does cyanide affect the cytochrome c oxidase?
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Which of the following components is part of complex III?
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What is true about the treatment of cyanide poisoning?
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Which statement correctly describes the process of coupled respiration in mitochondria?
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Which lipoprotein is most likely to be elevated in a patient experiencing steatorrhea?
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What symptom is NOT typically associated with steatorrhea?
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In which stage might steatorrhea present without symptoms?
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Which fat-soluble vitamin deficiency is least likely to occur in a patient with steatorrhea?
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What is primarily transported by chylomicrons after dietary intake?
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What is a common manifestation observed in children with severe steatorrhea?
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Where do chylomicrons enter circulation after being assembled in the intestinal mucosa?
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What type of diarrhea is associated with fat malabsorption leading to steatorrhea?
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What is the main effect of atractyloside on the ADP/ATP translocase?
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How does the mitochondrial membrane affect proton movement?
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What is the consequence of inhibiting ATP synthase with oligomycin?
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What role does the proton gradient play in the electron transport chain?
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Which process is directly halted due to inhibition of the part of the electron transport chain between complexes III and IV?
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Which of the following correctly describes a result of proton extrusion into the intermembrane space?
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What is the primary function of the electron transport chain?
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Which statement about oxygen's role in the electron transport chain is correct?
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Which medication can convert oxyhemoglobin to methemoglobin, thus increasing competition for cyanide binding?
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What is the primary role of cytochrome a/a3 in the presence of competitive inhibitors?
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What effect does increasing the percentage of oxygen breathed have on competition with cyanide?
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Which component of the electron transport chain (ETC) is primarily affected by cyanide poisoning?
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Which of the following statements about methemoglobin is correct?
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Which component of the electron transport chain is responsible for transferring electrons to oxygen?
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What is the primary consequence of cyanide binding to cytochrome a/a3?
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Which of the following medications may NOT compete with cyanide for binding to cytochrome oxidase?
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What is the primary function of bile produced in the liver?
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What will happen to fat when Sudan III dye is added to it in the presence of water?
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Which condition is specifically associated with the inability to absorb bile acids due to distal ileal resection?
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What type of obstruction is referred to by cholestasis?
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What does the term emulsification refer to in the context of lipid digestion?
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Which of the following is a consequence of primary sclerosing cholangitis (PSC)?
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Which laboratory result indicates the presence of triglycerides in a stool sample?
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What is a common result of small intestinal bacterial overgrowth (SIBO)?
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Study Notes
Electron Transport Chain Inhibition
- Inhibition can occur between complexes III and IV or between complex IV and mitochondria, impacting electron transport, ATP formation, or ADP/ATP translocation.
- Proton pumping is essential for creating a proton gradient across the inner mitochondrial membrane, allowing ATP synthesis.
- A proton gradient develops due to mitochondrial membrane's impermeability to protons, driving proton flow through ATP synthase.
Role of Inhibitors
- Atractyloside inhibits ADP/ATP translocase, preventing ADP from entering mitochondria while stopping ATP export, leading to a failure in ATP production.
- Oligomycin directly inhibits ATP synthase, causing proton accumulation in the intermembrane space and cessation of electron transfer.
- Cyanide ion (CN−) is a potent inhibitor of complex IV, competing with oxygen for binding sites on cytochrome c oxidase.
Mechanism of Cyanide Poisoning
- Cyanide binding to cytochrome a/a3 prevents electron transfer to oxygen, disrupting cellular respiration.
- Treatment involves enhancing oxygen levels to outcompete cyanide binding and administering nitrite ion, which converts hemoglobin to methemoglobin to further compete with cyanide.
Steatorrhea
- Defined as increased fat excretion in stools, characterized by bulky, pale, foul-smelling, and oily stools.
- Can be asymptomatic in early stages; children may experience growth failure and delayed puberty due to fat malabsorption.
- Causes include primary biliary cholangitis, primary sclerosing cholangitis, ileal resection, or bacterial overgrowth.
Significance of Chylomicrons
- Chylomicrons transport dietary cholesterol and triglycerides from the intestine to the bloodstream via the lymphatic system.
- They are assembled in the intestinal mucosa, entering circulation at the left subclavian vein.
Diagnostic Tests for Steatorrhea
- Sudan III dye test identifies fat in stools; lipid presence stains red, indicating fat malabsorption.
- In cases of steatorrhea, oil separates and floats in the solution due to lower density, forming a visible layer above water.
Bile Production
- Bile, produced in the liver, is crucial for fat digestion and absorption, delivered through the biliary duct to the duodenum.
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Description
This quiz explores the mechanisms of inhibition in the electron transport chain, focusing on the roles of various inhibitors like cyanide, atractyloside, and oligomycin. Understand how these inhibitors affect ATP production and the proton gradient essential for cellular respiration.