Bio 7 - Glycolysis Flashcards
How many ATP can cells using the Malate-aspartate shuttle produce?
32 ATP.
How many ATP can cells using the Glycerol-3-phosphate shuttle produce?
30 ATP.
Where are GLUT-1 proteins found in the body?
RBCs, Endothelium of the blood-brain barrier and other tissues. They take up glucose regardless of insulin levels.
Where are GLUT-2 proteins found in the body?
Hepatocytes and Pancreatic beta cells. They regulate glucose.
Where are GLUT-3 proteins found in the body?
Neurons and placenta.
Where are GLUT-4 proteins found in the body?
Skeletal muscles. Adipose tissue. They require insulin.
Where are GLUT-5 proteins found in the body?
Fructose uptake in the GI tract.
Why do we need to phosphorylate a glycose as soon as it enters the cell?
To trap it inside the cell. We do so by adding a phosphate group from ATP. It becomes glucose-6-P.
How can RBC produce ATP?
Anaerobic Glycolysis (2 ATP). They don’t have mitochondria.
What are the 2 enzymes that can phosphorylate glucose?
Hexokinase and glucokinase.
What is the difference between hexokinase and glucokinase?
Glucokinase is unique to cells that regulate glucose levels (liver and beta cells), has a very high km (needs a lot of substrates to hit a decent velocity reaction), has a high Vmax (once it starts working, it is very efficient and quickly), INDUCED by insulin. Hexokinase it has a much higher affinity for glucose, and lower Km (glucose conc doesn’t have to be as high in order to function), NOT induced by insulin.
What is the rate-limiting enzyme in glycolysis And what does it do?
Phosphofructokinase-1. Turns fructose-6-phosphate to fructose-6-phosphate-bisphosphate.
What enzyme converts phosphoenolpyruvate to pyruvate? What substances stimulate this enzyme and which ones inhibit it?
The is pyruvate kinase. It is stimulated by fructose1,6-bisphosphate. ATP and alanine are inhibitors.
What is the clinical presentation Glycolytic enzyme deficiency and what is the most common cause of it?
Hemolytic anemia, due to inability to maintain Na/K ATPase, causing RBC swelling/lysis. A common cause of this is pyruvate kinase deficiency.
A muscle biopsy on a patient reveals elevated glycogen levels, elevated fructose 6-phosphate, and decreased pyruvate. What enzyme deficiency do you suspect most?
Phosphofructokinase-1.
