Flashcards in 2.1-Secondary Carb Pathways Deck (36):
Where are the three steps in glycolysis that Fructose can enter (what tissue type for each?)
1. Step to Fructose-6-Phosphate (from adipose tissue-Burning Fat goes to Fructose!) 2. Step 4b DHAP (Liver) 3. Step 4a G-3-P (Liver)
What are the three sources of Fructose in our diet? How is High Fructose Corn Syrup different from Sucrose?
1. Pure Fructose 2. High Fructose Corn Syrup 3. Sucrose. HFC=NO covalent bonds; Sucrose=Covalently bonded
Which enzyme hydrolyses Sucrose in the small intestine? What "type" of enzyme is it?
A "Brush Border" Enzyme-Sucrase Isomaltase (S.I.)
What happens with an SI deficiency? Think Biome taking over...
Which GLUT transporter absorbs Fructose from the Gut into the cell? Which GLUT transports Fructose from the cell to the Blood?
Gut to Cell= GLUT5; Cell to Blood= GLUT2
Is there a limit to Fructose absorption in the Small Intestine?
Yes, Excess goes to the colon and causes Diarrhea
What are the two locations for Fructose catabolism? What is the bigger one?
Muscle & Liver... MUCH more going on in the liver
What is the step that gets Fructose into Glycolysis in muscle cells? What is the enzyme used?
Fructose ------->Fructose-6-Phosphate. The enzyme that does this is HEXOKINASE (WEIRD, I know. Phosphorylating a 6 carbon molecule...)
What are the two key enzymes in getting Fructose into glycolysis in the LIVER? Which one is "fast", which one is "slow"?
1. FructoKinase 2. Aldolase B
What does FructoKinase do?
Phosphorylates Fructose---->Fructose-1-Phosphate. WHAAA?
What does Aldolase B do?
Splits Fructose-1-Phosphate into 1.G-3-P and 2.DiHydroxyAcetonePhosphate (DHAP)
What gets by bypassed in Fructose metabolism in the liver? What is the consequence? THIS HITS HOME :)
PFK1 gets bypassed making more Acetyl-CoA which will then start making FAT
What is the result of high Fructose intake and then sequestering of inorganic Phosphate?
HyperUricemia and therefore GOUT. LOOK OUT cause its comin for ya! (ALDOLASE B gets backed up and saturated)
Which is more severe a FructoKinase deficiency or an Aldolase B deficiency? Why?
Aldolase B deficiency is more severe because the F-1-P gets stuck in the cell and gathers iPhosphate. (FructoKinase deficiency just excretes fructose from the body)
How does the less popular monosaccharide MANNOSE enter glycolysis?
Mannose---->Fructose-6-Phosphate (by a couple of enzymes) and you're good to go!
What is the sugar alcohol made from glucose in the cell? What unique function does this have?
Sorbitol! Helps trap glucose in the cell!
Which enzyme is lacking in the lens, nerves, and kidney that causes a build up of sorbitol?
What are the 4 enzymes that participate in the conversion of Galactose to G-6-P?
1. GalactoKinase 2. Galactose-1-Phosphate Uridylyl Transferase 3. UDP-Galactose-4-Epimerase 4.PhosphoGlucoMutase
What are the two alternate names for the Pentose Phosphate Pathway?
1.Hexose MonoPhosphate Shunt 2. PhosphoGluconate Pathway
What are the two main products of the Pentose Phosphate Pathway?
1. NADPH (for anabolism of things-steriods,complex carbs) 2. Ribose-5-Phosphate (for NucleoTides!)
What fatty acid synthesis areas are really active in PPP? What is the important area that IS NOT active in PPP?
MammaryGlands, Adipose Tissue, Adrenal Cortex, Liver.....MUSCLE dont care
What is the key reaction in the oxidative PPP pathway?
Glucose-6-P----->Lactone USING: Glucose-6-Phosphate Dehydgrogenase
How many NADPHs are yielded from the oxidative PPP pathway?
What is the key of the NON oxidative pathway?
If cell needs NADPH to build things, it can recycle Ribose-5-Phosphate
What happens when you are low on Ribose-5-Phosphate? What are the two starting ingredients?
Reverse PPP and make more from Fructose-6-Phosphate and Glyceraldehyde-3-Phospahte?
Which part of PPP is dominant when NADPH and Ribose-5-Phosphate are balanced your cell?
The Oxidative Part
What happens when you are low on NADPH?
GlucoNeoGenesis will make more Glucose-6-Phosphate to then go through the Oxidative PPP!
What happens when BOTH NADPH and Ribose-5-Phosphate are low?
Couple PPP with Glycolysis!
What is the enzyme that detoxifies H2O2 to H2O? What enzyme rejuvenates this enzyme to get back to work?
Glut-A-Thione Peroxidase...Reduced by GlutAThione Reductase
What is the antioxidant GlutAThione made of?
3 amino acids (a tripeptide!)
What is the #1 genetic deficiency in all Z world?! Where is the first place you will see it??
Glucose-6-P Dehydrogenase Deficiency..in the RBCs
Why is the #1 genetic deficiency a problem in RBCs?
There is lots of Free Radical Oxygen in RBCs and they do not have the enzyme to take care of it!
What is the clinical name for the deficiency of the enzyme Glucose-6-Phosphotase Dehydrogenase in a RBC?
Which enzyme converts Glucose to Sorbitol?
Is G6DP inhibited by NADPH?