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13 Cards in this Set
- Front
- Back
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What is Positive Energy Balance?
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E Intake> E output
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What are the basic strucutral units of starch, lactose and sucrose?
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Starch: Glucose
Lactose: Glucose + Galactose Sucrose: Glucose + Fructose |
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What are carbohydraes used for?
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1) End up somewhere in glycolytic pathway
2) Storage as glycogen 3) FA synthesis |
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Where does carbohydrate metabolism take place?
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Mostly in the liver
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How is Fructose metabolized in the liver?
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-Very little hexokinase in the liver, so liver uses Fructokinase to convert fructose-> F1P (traps fructose in the cell)
-F1P-aldolase converts F1P -> to Glyceraldehyde + DHAP (This is a Type B aldolase) -Convert glyceraldehyde to GAP so it can enter glycolytic path using Glyceraldehyde kinase -DHAP --> GAP using Triose Phosphate Isomerase, since only GAP goes through glycolysis |
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How does muscle integrate fructose into the glycolytic path?
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-Hexokinase converts Fructose -->F6P so it gets trapped
-F6P then enters glycolytic path before PFK point of control |
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What are th two types of Aldolases?
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Type A: Used in muscles. Uses F-1,6-bisphosphate and is used in step 4 of glycolysis
Type B: Used in liver. Uses F1P |
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Where doe fructose enter glycolytic path in muscle? In the liver?
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Muscle: Enters at step 2 as F6P, before PFK pt of control
This way, you can metabolize fructose according to demand Liver: Enters after step 4 as GAP and DHAP, after PFK .: it will go down glycolysis path regardless of cell's needs (accumulate intermediates) |
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What happens in Fructose Intolerance?
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-Fructose intolerant because lack F1P-aldoase .: get build up of F1P, which reduces lvls of ATP and Pi, so can't produce ATP in mito (no Pi)
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How is galactose metabolized in the liver?
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-Use Galactokinase to turn Galactose-->Galactose1-P, which traps it in the liver
-React Gal-1-P with UDP-Glucose to get UDP-Galatose + G1P (glucose1-P), using the Gal-1-P uridylyl transferase -G1P is then converted to G6P using phosphoglucomutase -G6P can now enter glycoltic path after just 1 step (Enters before PFK pt of control, so can be processed according to the cell's E demand)) |
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What is galactosemia?
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Inability to convert galactose to glucose
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How many types of galactosemia are there? What are they?
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3 Types
Type I: uridylyl transferase deficiency -(UDP-glu + gal-1-P -X-> UDP-gal +G1P) -Build up of Gal-1-P -Deplete ATP and Pi, can't make ATP Type II: Galactokinase deficiency -can't P galactose to Gal-1-P .: can't trap galactose Type III: Epimerase deficiency -lacks UDP-galactose-4-epimerase -build up of UDP-galactose |
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How can you form lactose if your galactosemic?
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Need glucose +UDP-galactose to form lactose
-Use G6P and work backwards -G6P--> G1P -G1P + UTP --> UDP-Glucose -UDP-Glu-->UDP Galactose These rxns works because phosphoglucomutase and the epimerase both work in both directions -The UDP-Gal generated can combine with glucose and using lactose synthase, you can get lactose **if type I and II deficiency, this won't work |
