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11 Cards in this Set
- Front
- Back
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Digestion of Sugar Process |
1. a Amylase in the salivary glands breaks the 1-4 linkages present in sugars to make a dextrins 2. Salivary amylase is dead and denatured once it reaches the stomach d/t acidity, but pancreatic a Amylase and bicarb are secreted to break down dextrins into 3-8 residue oligosaccharides 3. Maltase, isomaltase, take up glucose, whereas sucrose (Glu+Fru) via sucrase and Lactose (Glu+Gal) via lactase is moved across the gut epithelium and absorbed |
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Digestion of Fatty Acids Process |
1. Similar to the previous, but not breakdown occurs in the mouth 2. Once FA reaches the gut, Bile Salts are secreted to make a FA packed chylomicron, and bicarb/lipase/and colipase break up the chylomicron and release free fatty acids to gut wall via peristalsis 3. Gut absorbs FFA and 2MG which are packed into triglycerides and then nascent chylomicrons in the blood stream |
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Protein Digestion |
1. Specific enzymes that are not just responsible for repeating linkages. 2. Protein are broken down into peptides by stomach HCL and peptides. These peptides are broken down by specific enzymes that are initially inactive (Zymogens). 3. Final products post activation are amino acids and sent to circulation |
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Zymogens and examples |
Proenzymes are cleaved into active enzymes and cause confirmational c hanges 1. Pepsinogen---(H+)---> Pepsin (Stomach) 2. Trypsinogen---(enteropeptidase)--->Trypsin (Gut wall) 3. Chymotrypsinogen---(trypsin)--->Chymotrypsin 4. Proelastase---(trypsin)--->Elastase 5. Procarboxypeptidasase---(trypsin)--->Carboxypeptidase |
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Pepsinogen and Pepsin |
- Pepsinogen is secreted by parietal cells of the stomach and pH low and H+ concentration makes the cleavage -Pepsin by itself would eat through organ or be denatured |
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Trypsinogen and Trypsin |
-Pancreas releases trypsinogen which is cleaved by enteropeptidase in the gut wall. Trypsin is used to cleave other zymogen enzymes -Reason for this is that trypsin is soluble and can interact with zymogens within the gut fluid and protein breakdown can really get rolling |
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Carboxypeptidases |
Exoprotease, meaning it cleaves from the carboxy end |
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Chymotrypsinogen mechanism |
1. Chymotrypsinogen is initially inactive 2. Trypsin cleaves SPECIFICALLY between 15 and 16 Arginine and Isoleucine to make piChymotrypsin 3. Again another cleavage occurs to make another active alphaChymotrypsin Each have a specific place they are cut! What ever is between and cut out is lost |
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Nomenclature of enzymes in this state |
-If you start at the amino position pre-cleavage, you will then be at the carboxy terminus of the product -All specificity is dedicated by where on a protein you cut! |
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Carboxypeptidase A vs. Carboxypeptidase B |
-Carboxypeptidase A is hydrophobic -Carboxypeptidase B splits arginine and lysine -Both are responsible for removing whatever is at the carboxy terminus of the peptide |
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Uptake of amino acids |
-Very dependent on facilitated transportation and concentration gradient -- Gut has huge volume- Cell's is small- this creates small problem - To fix this, amino acids ride in on sodium because sodium is always lower in the cell and it works with the concentration gradient. --Sodium stays low via NKATPase -Amino acids can simply get into the portal circulation because volume discrepancy between cells and venous system. |
