1. Molecular breakdown/absorption of Polysaccharides Lipids Proteins
Stage 1 Digestion
Molecular breakdown/absorption of
Polysaccharides
Lipids
Proteins

3. Starches
MOUTH: salivary amylase hydrolyzes some glycosidic bonds of amylose
Formation of dextrins: 3-8 glucose units
STOMACH (pH 2)
denatures salivary amylase –stops further carb digestion
DUODENUM/PANCREAS
Secretion of pancreatic amylase completes digestion to maltose

4. STARCHES SMALL INTESTINE Mucosa cells lining SI secrete
lactase
Lactose → galactose + glucose
sucrase
Sucrose → fructose + glucose
maltase
Maltose → glucose + glucose
Absorption of monosaccharides into blood stream

5. Lipids Mouth- Stomach: no effect on lipids DUODENUM: bile salts
from the gall bladder
emulsify fat into tiny
droplets called micelles

6. Lipids DUODENUM Pancreatic lipase hydrolyzes lipids
triglycerides → monoglycerides + 2 FA
SMALL INESTINE
Absorption into blood stream
Transport in the blood via lipoprotein vesicles

7. Proteins MOUTH: no effect on proteins STOMACH contains HCl, pH 2
a. General acid denaturing of proteins
b. Secretion of enzyme pepsin hydrolyzes peptide bonds, formation of small peptides
pepsin
Proteins → peptides

8. Proteins DUODENUM/PANCREAS
Pancreatic enzymes Trypsin/ Chymotrypsin hydrolyze peptides into AA
SMALL INTESTINE
AA are absorbed into blood stream