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28 Cards in this Set
- Front
- Back
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The role of hepatocytes are:
Manufacture _____ including _____. Synthesize, store, and process _____. Metabolize and store _____. Form and secrete _____. Eliminate _____ and other harmful biproducts of the body. _____, by metabolizing and/or secreting, drugs, alcohol, and environmental toxins. |
Proteins, albumin
Fats Carbohydrates Bile Bilirubin Detoxify |
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_____ is the name given to a special liver form of the enzyme hexokinase.
How does it differ from hexokinase? |
Glucokinase
Has a higher Km for a sugar substrate (Important for the liver being the major source of glucose in the body) |
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What two processes does glucokinase facilitate?
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Creates glucose-6-phosphate as well as glycogen synthesis
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Glukokinase is also the predominant enzyme for the phosphorylation of glucose _____ cells of the _____.
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Beta, Pancreas
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What are the three regulatory enzymes of glycolysis?
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Hexokinase
Phosphofructokinase Pyruvate kinase |
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What two organs take up the extra glucose released back into circulation from the liver?
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Muscle
Brain |
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What is the major fuel for the brain?
Why does it rely solely on the availability of it through the blood? |
Glucose
It has no significant glycogen stores |
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What do RBC's oxidize glucose into?
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Pyruvate
Lactate |
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When does the liver release glucose into the blood?
Where is this released glucose derived from? |
Muscular activity and interval between meals
Breakdown of stored glycogen Formation of glucose through gluconeogenesis |
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Fasting leads to decreased liver _____.
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Glycogen
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What is another name for the Urea cycle?
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Ornithine cycle
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What is the overall reaction of the Urea cycle?
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2 Ammonia + Carbon Dioxide + 3 ATP = Urea + water + 3 ADP
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The two nitrogens enter the urea cycle as _____ and _____.
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Ammonia
Aspartate |
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Urea is produced by the hydrolysis of _____.
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Arginine
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The cleavage of _____ does not require ATP.
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Argininosuccinate
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The urea cycle occurs partly in the _____.
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Mitochondria
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Why is a complete block in the urea cycle fatal?
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There is no known alternative pathway for the synthesis of Urea.
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Inherited disorders from defective enzymes may cause a partial block in some of the reactions and results in _____, which can lead to what?
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Hyperammonia
Mental retardation |
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Extensive ammonia accumulation leads to extensive _____ damage and _____.
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Liver
death |
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What disease creates an interface in the enzymes that produce _____ _____ in the first step of the urea cycle?
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Carbamyl phosphate
Liver cirrhosis |
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The level of nonprotein nitrogen in the blood is due primarily to the level of _____.
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Urea
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What is the major regulatory enzyme of cholesterol synthesis?
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HMG-CoA reductase
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What is cholesterol synthesized from?
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acetyl-CoA
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What are the intermediates of cholesterol?
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HMG-CoA, mevalonic acid, isopentenyl pyrophosphate, squalene
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What vitamin is formed from cholesterol?
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Vitamin D
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Cholesterol absorption depends upon the presence of _____ _____ in the intestinal lumen.
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Bile Salts
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What is the feedback control of cholesterol synthesis?
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Cholesterol is in a negative feedback loop and causes allosteric inhibition of HMG-CoA reductase
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What are the enzymes involved in cholesterol synthesis that are reversible and do not commit the cell to the synthesis of cholesterol?
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Thiolase and HMG-CoA synthase
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