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PCAT Biological Processes – Digestive System

  • by Sam
  • Mar 20, 2018
  • PCAT Question of the Day

In the digestive system, triglycerides interact with amphipathic:

A) pepsin

B) bile salts

C) glycogen

D) sphingomyelin

Click for Explanation

Triglycerides are hydrophobic dietary fats.  In order to be absorbed by the digestive system, bile salts create small emulsions containing triglycerides. Bile salts themselves are created in the liver and stored in the gall bladder prior to release. Since bile salts are amphipathic, they can interact with the hydrophobic triglycerides and the aqueous environment of the digestive tract lumen.

A) pepsin, incorrect, Pepsin is the active catabolic enzyme of the zymogen pepsinogen, secreted by chief cells in the stomach.

B) bile salts, correct.

C) glycogen, incorrect, Glycogen is a branched polymer of glucose found primarily in muscle and liver cells.

D) sphingomyelin, incorrect, Sphingomyelin is a membrane sphingolipid found in animal cell membranes, especially those of myelinated nerve axons. Sphingomyelin is unlikely to be tested on the MCAT unless described in a passage.

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