Glycolysis/PDH Complex/TCA Cycle Flashcards
How does glucose become “trapped” inside the cell?
Hexokinase and glucokinase use ATP to phosphorylate glucose, and the GLUT transporters only recognize the non-phosphorylated glucose
Name the pathway of products through glycolysis
Glucose-> Glucose 6-Phosphate->Fructose 6-Phosphate->Fructose 1, 6-Bisphosphate->Glyceraldehyde 3-Phosphate->1,3-Bisphosphoglcerate->3-Phospholglycerate->2-phosphoglycerate->Phosphoenol Pyruvate->Pyruvate
What is the Km of Hexokinase?
Low Km, reaches max velocity at low glucose
What is the Km of Glucokinase?
High Km, acts proportionally with blood glucose concentrations
What is Hexokinase inhibited by?
Concentrations of Glucose 6-Phosphate
What is Glucokinase inhibited by?
Insulin
Where is Glucokinase located?
in hepatocytes and Beta-Islet cells
What is the rate limiting step/main control point of Glycolysis?
Phosphofuctokinase (PFK1)
In hepatocytes, PFK-1 is stimulated by?
Inhibited by?
Stimulated by insulin
Inhibited by Glucagon
What is PFK-1 inhibited by in cells other than hepatocytes?
ATP and citrate
What does Glyceraldehyde 3-phosphate dehydrogenase do?
Catalyzes oxidation and addition of an inorganic phosphate to Glyceraldehyde 3-phosphate to create high energy intermediate called 1,3-Bisphoglycerate
The oxidation and addition of a phosphate to Glyceraldehyde 3-phosphate provides something for Anaerobic metabolism, what is this?
It provides NADH for the reaction of pyruvate to lactate
3-phosphoglycerate kinase does what?
Transfers the high energy phosphate from 1,3 Bisphosphoglycerate to ADP, creating ATP and 3-Phosphoglycerate
Pyruvate kinase is activated by?
Fructose 1,6 bisphosphate
Which enzyme in Glycolysis is an example of feed forward regulation?
Pyruvate kinase
Which substrates are responsible for ATP production?
1,3 Bisphosphoglycerate and Phosphoenol pyruvate
Name the enzymes of glycolysis in order:
Hexokinase/glucokinase->Isomerase->PFK1->Aldolase->Glyceraldehyde 3-Phosphate Dehydrogenase->Phosphoglycerol Kinase->Mutase->Enolase->Pyruvate kinase
What is the Pyruvate Dehydrogenase Complex activated by?
In the liver by insulin
In nervous system-not responsive to hormones
The Pyruvate Dehydrogenase Complex is made of 5 enzymes, what are the 3 important ones?
Pyruvate Dehydrogenase
Dihydrolipoyl Transferase
Dihydrolipoyl Dehydrogenase
the Pyruvate Dehydrogenase Complex is inhibited by?
Acetyl-Coa
Where does glycolysis occur?
in the cytoplasm.
Where does the citric acid cycle occur?
in the mitochondria
What is the only pathway for ATP production in Erythrocytes?
Glycolysis
The difference between cellular glycolysis and glycolysis in erythrocytes is?
An enzyme called bisphosphglycerate mutase, which converts 1,3-Bisphosphoglycerate to 2,3 BPG which binds allosterically with HbA
