Digestion And Absorption Flashcards
Digestion
Hydrolysis of complex foods down into into simple soluble substances by enzymes
Physical and chemical breakdown of food
Large molecules hydrolysed into small
What are the in-folds in the small intestine?
Villi
Increase the surface area for absorption of small molecules from the lumen into the bloodstream
What are the in-folds called in the plasma membrane lining the epithelial cells in the small intestine?
Microvilli (in membrane of villi)
What are the three main types of carbohydrate?
Monosaccharides
Disaccharides
Polysaccharides
Which enzymes digest starch and what is produced?
Amylase
Maltose is produced then to glucose
Where are amylases produced?
Salivary glands
Pancreas
Which enzyme hydrolyses maltose and what is produced?
maltase
2 alpha glucose
Where are maltase, sucrase and lactase found?
Plasma membrane of epithelial cells lining the small intestine
What is the advantage to the cells to having these disaccharides located here?
Not secreted into the lumen
So can be re-used
Which enzyme digests lipids?
Lipase
Where is lipase produced?
Pancreas
What role would bile salts play in the digestion of lipids?
- Emulsify and break them down into smaller droplets
- increase the surface area for lipase to work on
- form micelles
What are the tiny droplets called that are made during emulsification?
Micelles
What enzymes digest proteins?
Peptidases (proteases)
Where are peptidases produced?
Stomach and pancreas
Endopeptidase
Digests internal peptide bonds
Produce molecules with more ends for the exopeptidases to digest
exopeptidase
Digests external peptide bonds
What is the location of membrane bound dipeptidases?
Membrane of intestinal epithelial cells
Role of membrane bound dipeptidases?
Hydrolyse dipeptides into separate amino acids
Name of the protein that moves two molecules through a membrane in the same direction?
Symport
Which ion is co transported into the cells together with the glucose molecule?
Sodium ions
micelle
A droplet of lipid surrounded by bile salts fatty acids or monoglycerides surrounded by bile salts
Chylomicrons
Triglycerides associate with cholesterol and lipoproteins to make them
How do chylomicrons move out the cell?
Exocytosis
