1.8-Glycolysis Flashcards
What is glucose converted to in aerobic conditions? Anerobic?
Aerobic:Pyruvate (2) Anerobic: Lactate
Where does glycolysis happen?
The cytosol
What is the ROLE of glycolysis in muscle?
Supply ATP for muscle contraction (frequently anaerobic)
What is the ROLE of glycolysis in the liver?
Converting excess glucose to FAT for storage
What is the ROLE of glycolysis in RBCs?
Supply ALL ATP (no mitochondria)
What is the ROLE of glycolysis in the Brain?
Glucose is primary fuel, glycolysis STARTS the conversion to ATP after oxidative phosphorylation
Do GLUTs move glucose with or against its [ ] gradient?
With [ ] gradient
Where are GLUT1s mainly found?
Brain and RBCs
Where are GLUT2s mainly found? What is Dr. Ts analogy for GLUT2s?
Mainly found in liver, kidney, intestine and Beta Cells(pancreas)….They are the Ferrari of GLUTs
Where are GLUT3s mainly found?
nearly ALL cells!
Where are GLUT4s mainly found?
Muscle and Adipose (insulin dependent)
Where are GLUT5s mainly found?
Small Intestine (on arterial side of the epithelial cell)
Which GLUT transporter has the highest Km?
GLUT2 BY FAR 15-10mM
Which tissues are insulin Independent? Think low blood supply or tissues ALWAYS involved with moving glucose…
Eye, Blood Cells (W&R), Liver, Brain
What is the name of the Sodium/Glucose Symporter what moves glucose from the lumen of the intestine to the epithelial cell?
SGLT1
What is the first thing that happens when Glucose enters any cell? What enzyme is used?
HexoKinase phosphorylates the glucose to make it G-6-P!
How many NADH do I get out of Glycolysis? How much ATP? If you get these wrong, you need to go back to high school.
2 NADH, 2ATP
What is the ONLY reason for Anerobic Glycolysis?
To empty the NADH taxi cab and make it NAD+ for Glycolysis!!
Where is anaerobic glycolysis particularly important? Think same as insulin independent tissue! Low Blood Supply!
Eye, Blood, Kidney Medulla, Testes
What is the enzyme that converts pyruvate to Lactate? Freaking straight forward!
Lactate DeHydrogenase
THIS IS BIG PEOPLE: What are the three Regulatory enzymes of Glycolysis? Why are they considered regulatory?
- HexoKinase 2. Pyruvate Kinase 3. PhosphoFructoKinase1 (PFK1)… They are “regulatory” because they catalyze steps that are irreversible (very energetically downhill)
Just more names to memorize: what is the isozyme of hexokinase in the LIVER?
GlucoKinase
What is the name for the hexokinase in the muscle? JK, but what is it allosterically inhibited by?
Its called Hexokinase, its allosterically inhibited by G-6-P (the product!)
Which hexokinase isozyme is inducible by the presence of insulin?
GlucoKinase
What does Glucagon do to the enzyme Pyruvate Kinase? What does that do glycosis overall in the liver?
It LOWERS its effectiveness by phosphorylating it. Since Pyruvate Kinase is lower in effectiveness glycolysis stops in the liver. (WE ARE HUNGRY STOP GLYCOLYSIS AND START GNG…IN LIVER ONLY!!)
MAJOR CONCEPT: What does Glucagon signaling generally end up with?
A Phosphorylation event. ADDING a phosphate
MAJOR CONCEPT: What does Insulin signaling generally end with?
A DEphosphorylation event. Taking off a phosphate
Which high energy molecules inhibit Pyruvate Kinase and there for slowdown glycolysis? (In all glycolytic tissues)
ATP, Acetyl-CoA, Long Fatty Acids
Which regulatory enzyme commits the cell to glycolysis? AKA the cross roads between glycolysis and gluconeogenisis…
PhosphoFructoKinase1 (PFK1)
What 4 molecules INCREASE PFK1 activity?
Molecules of Hunger: ADP, AMP, Fructose-6-Phosphate (Reactant), Fructose-2,6-BisPhosphate (mainly in liver)
What 2 molecules DECREASE PFK1 activity?
Molecules of Satiation: ATP, Citrate
How does insulin increase PFK1 activity? What enzyme does it stimulate? What product does it yield? Where does this “round about” reaction mainly occur?
Insulin stimulates the enzyme PFK2 to make Fructose 2,6 Bisphosphate. Fructose 2,6 Bisphosphate is very stimulating for PFK1 IN THE LIVER
What effect does glucagon have on Fructose 2,6 Bisphosphate in the liver?
Glucagon inhibits Fructose 2,6 Bisphos to promote GNG
What is the liver ultimately trying to make when there is high insulin to glucagon ratio in the blood?
The liver is performing glycolysis with the goal of ultimately turing pyruvate to FAT
