320SummerHomework7-answers - Cell Biology(BIO 320 Summer...

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Cell Biology (BIO 320), Summer 2008, Dr. Bushart Homework for quiz 6 1. How might gap junctions be contributing to the excessive apoptosis seen in heart attacks and strokes? Just as importantly, what component(s) is(are) unlikely to be a factor in this process? Some factor may be moving through gap junctions, from the cells undergoing necrotic cell death to neighboring cells that would otherwise survive. This factor is inducing apoptosis in some fashion. What it is NOT likely to be is any type of protein, such as caspases or cytochrome C, since gap junctions are limited in the size of molecules that can pass through them. As mentioned in lecture, ions like Ca2+ and small molecules like nucleotides are candidates. 2. Intestinal endothelial cells are capable of altering their tight junctions to allow for paracellular transport of amino acids after meals. In terms of energy expenditure, why is this beneficial? After a meal, the amino acid concentration of the lumen of the intestine is going to be significantly higher than that of the extracellular fluid on the basolateral side of the
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This note was uploaded on 08/31/2009 for the course BIO 320 taught by Professor Staff during the Summer '08 term at University of Texas.

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320SummerHomework7-answers - Cell Biology(BIO 320 Summer...

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