Biomolecule Absorption

Digestive System

Processing of food for distribution to the body’s tissues and cells

Biomolecule Absorption/Digestion

Types:

• Mechanical
• Chemical

Micro Fundamentals:

• Digestion of compounds within lysosomes is a form of intracellular digestion
• Extracellular digestion which occurs outside the cell’s borders
  • Occurs within the lumen of the alimentary canal

Macro Fundamentals:

• Molecules cross into cells that line the small intestine
• Ultimate transport to the blood

Simple Absorption across plasma membrane

• Protein - Intestinal transporters
• At least seven
  • Specific for a different group of AAs
• Carbohydrates - Sodium-glucose cotransporter
  • Secondary active transport
• Lipid
  • lymph then blood

Specifics:

Proteins

• Peptidases on external surfaces of cells break oligopeptides into amino acids, tripeptides, dipeptides
  • tri/dipeptides processed further by peptidases

Carbohydrates

• Glucose, Fructose, Galactose
• Amylases free or on external surfaces of cells break polysaccharides into monosaccharides

Lipids

• Emulsion and plamsma membrane

LOC:

• Small intestine