Fred may have consumed biomolecules such as proteins and lipids, but
did you know that the cells in Fred (and in humans) also possess organelles
that are made of these two biomolecules? Most cell organelles are membranes
consisting of lipids and/or proteins. That's right... the lipid you ate
yesterday could be living a new life as part of a plasma membrane tomorrow.
Click on an organelle in the cell image above to learn more about it.
Absorption into a Cell
- Carbohydrate Absorption
- Mostly all are absorbed as monosaccharides (simple sugars). The absorbed carbohydrates will mostly function to provide an available source of energy to drive metabolic reactions. Some other carbohydrates will go on to build structures that generate ATP (adenosine triphosphate, energy). Carbohydrates are stored in animals (and Fred) as glycogen.
- Lipid Absorption
- Because the plasma lipids (triglycerides, fatty acids, and cholesterol) are insoluble in water, they must be combined with protein carriers, or apoproteins. These lipid-protein combinations act as building blocks for every one of Fred's cell membranes, and they also play a major role in hormone production.
- Protein Absorption
- Proteins are broken down into amino acids in the stomach by means of the enzymes found in pancreatic juices. Most proteins are absorbed in the duodenum and jejunum as amino acids. Some amino acids are absorbed by the epithelial (surface) cells of the villi by means of active transport. They then diffuse into the blood stream and are carried to the liver. Proteins take on so many functions in the body including muscle development and regulators (enzymes) for control of body systems.