Chemical Digestion

1. Enzymatic Hydrolysis ("water" "breaking")
• hydrolysis - a water molecule is added between two "monomers" of a complex organic molecule in order break it down into its component parts
2. Carbohydrate Digestion
• monosaccharides - "monomers" such as glucose, fructose, and galactose
• disaccharides - sucrose (table sugar), lactose (milk sugar), and maltose (grain sugar)
• polysaccharides - starch (grains), glycogen (muscle)
• carbohydrate hydrolyzing enzymes
• salivary amylase - produces "oligosaccharides"
• pancreatic amylase - in small intestine
• intestinal enzymes - dextranase & glucoamylase (> 3 sugars), maltase, sucrase, and lactase
• lactose intolerance - decreased ability to digest lactose in the diet (use "lactase" supplements)
3. Protein Digestion
• amino acids - the "monomer" components of protein
• stomach - pepsinogen -----> pepsin (low pH)
• small intestine
• enzymes that cleave throughout the protein
• trypsinogen ---------------> trypsin
• chymotrypsinogen ------> chymotrypsin
• carboxypeptidase (carboxyl end of protein)
• aminopeptidase, dipeptidase (amino end)

4. Lipid (Fat) Digestion
• lipid structure - glycerol + 3 triglycerides
• lipases - enzymes that break down lipids
• bile salts - "emulsify" fats in 1 micron "micelles"

5. Nucleic Acid Digestion
• pancreatic nucleases - break down DNA and RNA

Category: Physiology Notes