Glycolysis Flashcards
Carbohydrates are broken down into ____ (glucose, galactose), which are then absorbed by intestinal lining by ___ ____
monosaccharides; facilitated diffusion
When your body intakes carbs and fats and breaks them down to form ATP, what are the chemical waste products?
CO2, H2O
Where does glycolysis occur in the cell?
cytosol
Name the requirements of glycolysis and also the products
requirements: Glucose, 2 Pi, 2 ADP, 2 NAD+
products: 2 pyruvate, 2 ATP, 2 NADH, 2H, 2H2O
In glycolysis, one glucose molecule is covered to ___ pyruvate molecules
2
Glycolysis is the only pathway to produce ATP without ____
oxygen
Availability of glucose for glycolysis is controlled by transport into the cell, which is regulated by _____
insulin
Glucokinase and Hexokinase can both catalyze the first step of glycolysis. Name the differences between them in regards to location, affinity, and inhibition by G-6-P
Glucokinase: liver and kidney; low affinity; not inhibited
Hexokinase: all tissues; high affinity; inhibited
True or false? The function of glucokinase is to remove glucose from the blood following a meal, while hexokinase acts at a constant rate
true
What is the key regulatory step of glycolysis and also the committed step?
F-6-P to F-1,6-BP
enzyme is phosphofructokinase
In the 6th step of glycolysis, G-3-P to 1,3-BPG, NAD+ must be regenerated for glycolysis to continue. True or false?
True
1,3-BPG is the source of 2,3-BPG in ____
erythrocyte
Enolase is inhibited by ____
fluoride
note: for estimation, blood sample is collected in tubes containing fluoride to inhibit glycolysis
After glycolysis has finished, what determines which of the two pathways is followed (aerobic or anaerobic)?
redox state of tissue
In aerobic glycolysis, pyruvate is converted to acetyl-CoA in the ___ for the TCA cycle
mitochondria
The oxidation of acetyl-CoA by the TCA will account for additional ___ molecules of ATP per glucose molecule
36
Under aerobic conditions, NADH produced may be effectively reoxidized by the mitochondria through the “____ ____”
shuttle system
In regards to anaerobic glycolysis, what enzyme is used to regret NAD+?
lactate dehydrogenase
The NAD+ must be regenerated for glycolysis to continue. Since NADH cannot cross mitochondrial membrane, the reducing equivalents from the NADH formed in glycolysis are taken up into mitochondria for oxidation by ____ mechanism
shuttle
List the steps of glycolysis that use ATP and produce ATP
Use ATP:
glucose to G-6-P = -1 ATP
F-6-P to F-1,6,-BP = -1 ATP
------------
-2 ATP
Produce ATP:
Glycerate-1,3-BP to 3-P-glycerate = + 2 ATP
PEP to pyruvate = +2ATP
————
+4 ATP
net gain: 2 ATP
Regulation of glycolysis is controlled primarily by three enzymes: hexokinase, PFK-1, and pyruvate kinase. Give the activator and inhibitor of hexokinase
Activator: none
inhibitor: G-6-P, ATP
Regulation of glycolysis is controlled primarily by three enzymes: hexokinase, PFK-1, and pyruvate kinase. Give the activator and inhibitor of PFK-1
activator: F-2,6-bP, AMP
inhibitor: Citrate, ATP
Regulation of glycolysis is controlled primarily by three enzymes: hexokinase, PFK-1, and pyruvate kinase. Give the activator and inhibitor of Pyruvate kinase
activator: F-2,6-bP, AMP
inhibitor: Acetyl-CoA, ATP
In regards to the bisphosphoglycerate pathway in erythrocytes, bisphosphoglycerate mutase forms 2-3 BPG which binds to ___, decreasing its affinity for ___
Hb; O2
In liver, kidney, and intestine, fructokinase phosphorylates fructose to fructose-1-phosphate. Diabetic patients can clear fructose because they are not affected by ____
insulin
Galctosemia is the result of a lack of what enzyme?
galactose-1-phosphate uridyltransferase
Fructose, Galactose, and Mannose enter the ____ pathway for metabolism
glycolytic
