13.23 Digestive System Lacteals and Absorption

13.23 Digestive System Lacteals and Absorption

By Stacy King

​Carbohydrates

• simple are monosaccharides or disaccharides

• complex ​are polysaccharides

​Proteins

• amino acids

• polypeptides​

  • secondary -pleated sheets or helix

  • Tertiary

  • Quaternary or Globular

​

​Biomolecules

​

Monosaccharides =one sugar, include:

• Glucose = C₆H₁₂O₆ made by plants during photosynthesis and is the main monomer of carbohydrates

• Fructose = found in fruit juice

• Galactose= found in milk

Disaccharides =Two sugars

• made by dehydration synthesis

• Sucrose=table sugar

• Lactose=sugar found in milk

• Maltose= formed when polysaccharides break down

Polysaccharides= many sugars

• Starch =how plants store their extra sugar

• Glycogen= how animals store their extra sugar

• Cellulose=builds plant cell walls, indigestible fiber

​​​Lipids

​composed of fatty acids

• saturated

• unsaturated

• polyunsaturated

​Types of lipid containing molecules

• ​Triglycerides

• ​Phospholipids

• ​Steriods

​Biomolecules

​

Biomolecules​

​The villi of the small intestine are folds that increase suface area for asorption, especially the ileum. The villi have smaller projections called microvilli that contain the brush border and absorb biomolecules.

​How does absorption take place in the intestines?

• ​Glucose and amino acids are absorbed by diffusion into the blood capillaries of the villi.

• ​Glucose and amino acids are also absorbed by active transport.

• ​Glycerol and fatty acids diffuse into the epithelium, then combine to form minute fat globules which enter the lacteals.