- The principal product of fat digestion by pancreatic lipase is the free fatty acids (FFAs) and which one of the following?
(1) 3-monoacylglycerols (2) 2-monoacylglycerols
(3) 1-monoacylglycerol (4) 1, 3-diacylglycerols
Fat digestion is a critical part of the digestive process, enabling the breakdown of dietary triglycerides into absorbable components. Pancreatic lipase, secreted by the pancreas into the small intestine, plays the central role in hydrolyzing triglycerides. Understanding the principal products of this digestion process helps clarify how fats are absorbed and utilized by the body.
How Pancreatic Lipase Digests Fats
Dietary fats mainly consist of triglycerides, molecules formed by glycerol esterified to three fatty acids. Pancreatic lipase specifically targets the ester bonds at the first and third positions of triglycerides.
-
Hydrolysis Process:
Pancreatic lipase cleaves the fatty acids at the outer positions (sn-1 and sn-3) of the triglyceride molecule, releasing two free fatty acids and leaving a monoacylglycerol. -
Position of Monoacylglycerol:
The monoacylglycerol produced is predominantly in the 2-position (sn-2) because the enzyme removes fatty acids from sn-1 and sn-3 positions.
Principal Products of Pancreatic Lipase Digestion
-
Free Fatty Acids (FFAs):
Released from the triglyceride during hydrolysis, FFAs are important for energy metabolism and are absorbed by intestinal cells. -
2-Monoacylglycerols:
The monoacylglycerol molecules primarily exist as 2-monoacylglycerol, a key intermediate absorbed intact by enterocytes and further metabolized.
Why Other Monoacylglycerols Are Not the Principal Product
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1-Monoacylglycerol:
Not the main product because pancreatic lipase does not preferentially leave the fatty acid in the sn-1 position. -
3-Monoacylglycerol:
Also unlikely as pancreatic lipase releases the fatty acid at the sn-3 position. -
1,3-Diacylglycerols:
These are intermediates in digestion but not the main products formed directly by pancreatic lipase.
Summary Table of Pancreatic Lipase Digestion Products
| Product | Description | Role in Fat Absorption |
|---|---|---|
| Free Fatty Acids (FFAs) | Hydrolyzed fatty acids released from triglycerides | Absorbed and metabolized by enterocytes |
| 2-Monoacylglycerol | Monoacylglycerol with fatty acid at the 2-position | Absorbed intact, re-esterified in enterocytes |
| 1-Monoacylglycerol | Monoacylglycerol at 1-position | Not principal product |
| 3-Monoacylglycerol | Monoacylglycerol at 3-position | Not principal product |
| 1,3-Diacylglycerols | Diacylglycerol intermediates | Not principal product |
Conclusion
The principal products of fat digestion by pancreatic lipase are free fatty acids and 2-monoacylglycerols. These products are essential for efficient absorption and subsequent metabolism of dietary fats.
Therefore, the correct answer is:
(2) 2-monoacylglycerols
