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17 Cards in this Set
- Front
- Back
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4 steps of digestion:
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1. mastication/emulsification
2. dissolution - add liquid 3. acid effects - stomach 4. enzymatic degradation |
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Protein digestion
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-endopeptidases - attack middle of a.a. chain
-exopeptideases - attack ends of a.a. chain |
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Zymogen
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inactive form of an enzyme so that it won't attack the proteins in the body. (pepsinogen or pepsin??)
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zymogen example
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trypsinogen - has a 6 a.a. mask that is taken off in the presence of enterokinase. this converts trypsinogen to the active enzyme trypsin.
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how many essential a.a. are there?
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8 - these come from corn/grains AND bean/legumes .. vegeterians must eat from both of these
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Carbohydrate digestion
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amylopectin (1,6 and 1,4 glucosidic linkages), sucrose, and lactose
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amylopectic digestion
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-salivary amylase (1,4 glucosidic linkages)
-stomach -> stops -pancreatic amylase (prefers 1,4) - |
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sucrose and lactose digestion
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small intestine
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cellulose
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humans can't digest beta 1,4 glucosidic linkages
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Lipid Digestion
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-bile salts
-emulsification -micelles - tiny fat cells that have been broken down by emulsification. they have a high SA:volume so they can be attached by lipase. -Lipase breaks into monoglycerols, fatty acids, and chylomicrons. move chylomicons to lymphatic vessels |
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What do the intestinal epithelial cells do to fat?
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package into chylomicrons
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Lipid Digestion (cont.)
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Bile Salts -> fat globules to micelles
Pancreatic Lipase -> micelles to 2 fatty acid and 2mono-glycerols |
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lipoproteins
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HDL - good ->remove cholesterol
LDL - bad -> rich in cholesterol VLDL - ugly -> carried to fat tissue |
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Absorptive State
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meal to 4 hrs.
-main energy source: glucose |
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Postabsorptive State
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only nervous system uses glucose -> for brain
-large quantities of protein in muc=scle if broken down to a.a. and sugars |
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gluconeogenesis
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liver breaks down a.a. to produce glucose
-biosynthesis of new glucose |
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glucose sparing
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cells use fatty acids as fuel to spare glucose for brain
-reduction of glucose catabolism and increase fat utilization by the tissues |
