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21 Cards in this Set
- Front
- Back
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What are the main differences between Fructose and Glucose Metabolism?
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Fructose does not require insulin
- Fructose does not stimulate Insulin Production - They are phosph by diff kinases - Fructose bypasses the regulated step |
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Where does Fructose Metabolism occur?
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Liver
Intestinal Mucosa Kidney |
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How does Fructose eenter teh cell?
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Non Insulin dependent GLUT (5) via facilitated diffusion
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What is fuctose entry into the cell dependent on?
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Fructose Concentration
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What enzyme cleaves 1-P-Fructose?
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Adolase B
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How can fructose be synthesized endogenousl?
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polyol pathway
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What tissue uses fructose as its primary source of energy?
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the spermatoazoa of seminal vesicles
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What is Fructose more lipogenic than glucose?
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Fructose does not have the regulated step/enzyme PFK1. So, will continually make DHAP and glyceraldehyde-3-P
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How is Fructose endogenously synthesized from glucose?
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The Polyol Pathway
- via Glucose is catalyzed by Aldoose reductase to Sorbitol - sorbitol is then catalyzed to Fructose. |
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Can you Synthesize Fructose from Glucose?
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Yes! Glucose goes to Soribitol which goes to Fructose. main enzyme involved with this is Aldose Reductase
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What happens if there is a build up of sorbitol? Where does this happen?
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The cells will swell.
- Aldose reductase, and No Sorbitol Reductase, is often found in lens, retina, nerve cells and kidney ce;;s |
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What is associated with Sorbitol Build up?
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Cataracts
Peripheral Neuropathy Complications with diabetes |
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What enzyme is messed up if you have a build up of fructose? How will you know that there is a build up of Fructose in a pt's body?
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- Fructokinase deficiency would result in fructose build up
- The excess fructose will get filtered thru the kidneys and come out in the urine |
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What is the result of Fructokinase deficiency? (also called Essential Fructosuria)
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Build up of Fructose
- comes out thru the urine - no known harmful Sx |
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What happens where there is a deficiency in Aldolase B? (also called Hereditary Fructose Intolerance)
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You will not only have a build up in Fructose-1-P but also a build up in fructose
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Aldolase B Deficiency AKA Hereditary Fructose Intolerance would result in what, clinically?
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Feeding problems
Enlarged livers other problems PLUS Fructose in Urine! |
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Who enters into Glycolysis first, Galactose or Fructose?
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Galactose
- enters at the Glucose-6-P phase --> Fructose enters at the DHAP stage |
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Are Galactose Glut Transporters Insulin Sensitive?
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NO
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What is Gal-1-P uridyl-transferase (GALT)
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Catalyzes Galactose-1-P to Glucose 1-P using UDP glucose as a helper
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What is Nonclassical Galactosemia AKA GALACTOKINASE DEFICIENCY
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- you get a build up of Galactose
- Aldose Reductase will break it down to Galactitol - causes CATARACTS!!! |
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What is Classical GALT Deficiency?
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- also causes Cataracts PLUS Severe Liver Damage!!!
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