Nutrient digestion and absorption Flashcards
What are the 3 monosaccharides ?
Glucose
Galactose
Fructose
Where are monosaccharides absorbed ?
Small intestine
What are disaccharides ?
2 monosaccharides linked by glycosidic bond
What breaks down disaccharides into monomers in small intestine ?
Brush border enzymes
What does lactase do ?
Breaks down lactose into glucose and galactose
What does sucrase do ?
Breaks down sucrose into glucose and fructose
What does maltase do ?
Breaks down maltose into 2 glucose
What are 3 polysaccharides ?
Starch- plants
Cellulose- plant cell wall
Glycogen- animal storage form of glucose
In glycogen what are glucose monomers linked by ?
Alpha-1,4 glycosidic bonds
What are proteins ?
Polymers of amino acids linked by peptide bonds
What do proteins undergo ?
Post-translational modification
What are small proteins called ?
Peptides
What enzymes breakdown proteins and peptides ?
Proteases and peptidases
What is the breakdown products of proteins and peptides ?
Amino acids
In what form is fat digested ?
Triacylglycerol
What enzymes digest fats ?
Pancreatic lipases
Are lipases water soluble ?
Yes
What is triacylglycerol broken down into ?
Monoglyceride + 2FAs
What is emulsification ?
Dividing large liquid droplets into small droplets
What does emulsification require ?
Mechanical disruption- smooth muscle contraction grinds and mixes lumenal contents
Emulsifying agents- bile salts + phospholipid secretion in bile
How is absorption enhanced ?
Formation of micelles
What are micelles ?
Bile salt + monoglyceride + FA + phospholipid
What is the product of micelle breakdown ?
Release of small amounts of free fatty acids and monoglycerides into solution that diffuse across plasma membrane of absorbing cells
Where do FAs and monoglycerides enter after entering epithelial cells ?
sER- where they are reformed into triacylglycerols
