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26 Cards in this Set
- Front
- Back
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What is found in the brush border of the small intestines that helps aid digestion?
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Enzymes for starch/protein breakdown, specifically hydrolases for oligosaccarides and oligopeptides.
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Where does starch digestion begin? Protein digestion? Fat digestion?
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-Starch- in the mouth with salivary a-amylases
-Protein- in the stomach -Fats- in the small bowel with bile salts from the liver |
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What does sucrose break down into?
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Glucose and fructose
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What does lactose break down into?
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Glucose and galactose
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How are glucose molecules in glycogen held together?
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alpha-1,4 linkages in chains; alpha-1,6 linkages at branches
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What type of enzyme is alpha-amylase (salivary and pancreatic)? What is the function of alpha-amylast?
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-An endo-glucosidase
-Cuts a starch/glycogen into smaller, 2-5 carbon oligosaccarides. Some are branched and others are straight |
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What is the activity of maltase?
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Maltase cleaves the alpha-1,4 between the two carbons of maltose.
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What is the activity of isomaltase?
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Isomaltase cleaves the alpha-1,6 bond between the two carbons of isomaltose.
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What is the activity of trehalase?
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Trehalose cleaves the alpha-1,1 bond between two glucose molecules joined together at their animeric carbons.
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Which end is the reducing end- the one with the -OH or the animeric carbon end?
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Reducing end- animeric carbon
Non-reducing end- ends in -OH |
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What type of enzyme is alpha-amylase (salivary and pancreatic)? What is the function of alpha-amylase?
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-An endo-glucosidase
-Cuts a starch/glycogen into smaller, 2-5 carbon oligosaccarides. Some are branched and others are straight |
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What is the activity of maltase?
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Maltase cleaves the alpha-1,4 between the two saccarides of maltose.
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What is the activity of isomaltase?
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Isomaltase cleaves the alpha-1,6 bond between the two saccarides of isomaltose.
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What is the activity of trehalose?
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Trehalose cleaves the alpha-1,1 bond between two glucose molecules joined together at their animeric carbons.
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Which end is the reducing end- the one with the -OH or the animeric carbon end?
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Reducing end- animeric carbon
Non-reducing end- ends in -OH |
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What is the activity of lactase?
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Lactase is a beta-galactosidase that cleaves the beta-1,4 bond between glucose and galactose.
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What is the activity of Beano??
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Beano is an alpha-galactosidase that cleaves the alpha-1,4 bond in raffinose. Humans do not have a naturally occuring alpha-galactosidase so raffinose (galactose + sucrose) so raffinose passes undigested into the bowel where bacteria ferment it and create gas!!
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What happens when indigestibles are fermented by colonic bacteria?
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-Produces gas (H2, CO2, and methane
-Produces short chain fatty acids (irritating to gut) -Produces lactic acid |
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What is the common name for b-galactidase deficiency?
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Lactase deficiency
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What is the common name for a-galactidase deficiency?
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Bad gas! (Humans don't have an a-galactidase enzyme!)
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How does sorbital not contain any calories?
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It can't be digested because there are no enzymes to break it down. It can cause diarrhea...
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What is the GI (glycemic index) for glucose? Peanuts?(White bread comes in at 100)
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Glucose 142
Peanuts 15 |
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How is glucose transported into the intestinal cell?
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Glucose can either passively diffuse into the cell or be transported via the glucose/Na+ symport transporter.
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GLUT 4 is a glucose transport protein. Where is it found? What turns it on? How?
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1) Found in skeletal muscle, adipose, and heart.
2) Activated by insulin (increase in number of transporters on the surface of the cell). 3)-Insulin binds to a receptor on the surface of the cell. -This signals GLUT 4 storage vesicles to release GLUT 4 transporters. -The GLUT 4 transporters are deployed on the plasma membrane. -In the absense of insulin, the GLUT 4 transporter is taken back up again by endocytosis and stored again in vesicles. |
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What is the difference in the way that glucose gets into the brain versus into the intestinal cells?
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-The blood brain barrier does not permit passive diffusion of glucose into the brain. The ONLY way that glucose can enter the brain is through the transport system.
-There are actually two transporters, one in each membrane (apical and basal), to get glucose past the blood brain barrier. |
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Why can't the brain use FA's as a fuel?
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FA's can't get through the blood brain barrier.
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