Topic 3- Enzymes in digestion Flashcards
Enzymes are substrate specific what does this mean?
different enzymes digest and breakdown the different biological molecules contained in food
What are the 3 main types of digestive enzymes?
-carbohydrases
-proteases
-lipases
Digestive enzymes are 1._____ enzymes, they work outside of cells
1.extracellular
Where does the digestion of carbohydrates take place?
Mouth and small intestine
Where is amylase made?
-salivary glands
-the pancreas
-the small intestine
What ennzymes hydrolyses carbohydrates into maltose?
Amylose
Which enzyme hydrolyses maltose into glucose?
Maltase
Where is maltase, sucrase and lactase found?
in cell-surface membranes of the epithelial cells lining the small intestine
What do maltase, sucras and lactase allow for?
absorption of monosaccharides into epithelial cells of the small intestine which pass them into the bloodstream
Are microvilli present on the surface of the small intrestine?
Yes- Increase SA
Where does protein digestion begin?
Lumen of the stomach
What is the 1st step of proetin digestion?
endopeptidase hydrolyses peptide bonds creating smaller protein chunks
What is endopeptidase secreted along with? What is the function of this?
-Hydrochloric acid
-pH in the stomach is low
What is the 2nd step of protein digestion?
partially digested food moves from the stomach into the small intestine
What is the 3rd step of protein digestion?
Fluid secreted by the pancreas travels to the small intestine and helps to neutralize the acidic mixture and increase the pH
What does the pancreatic juice contain?
Endopeptidases and exopeptidases
What is the function of endopeptidases?
hydrolyse peptide bonds within polypeptide chains to produce dipeptides
What is the function of exopeptidases/
hydrolyse peptide bonds on the end of polypeptide chains to produce dipeptides
there are dipeptidase enzymes found within the cell surface membrane of the epithelial cells in the small intestine, what do these hydrolyse?
dipeptides into amino acids which are released into the cytoplasm of the cell
What has to happen before the digestion of lipids?
Emulsification
Describe what happens in emulsification
-solid lipids are turned into a fatty liquid consisting of fat droplets
-When the fatty liquid arrives in the small intestine, bile (containing bile salts) (made in the liver,stored in the gallbladder) is secreted
-bile salts bind to the fatty liquid and breaks the fatty droplets into smaller ones via emulsification
Why is emulsification useful?
increases the surface area of the fatty droplets for action of digestive enzymes
Where does the digestion of lipids take place?
Lumen of the small intestine
Where are lipase enzymes produced?
In the pancreas
How are lipids digested?
Lipase enzymes break down lipids into glycerol and fatty acids
