glycolysis Flashcards
what is the end product in anaerobic glycolysis?
Lactate
what is the end product in aerobic glycolysis?
pyruvate
what tissues are GLUT-1 found in?
most tissues
esp. brain and RBCs
what tissues are GLUT-2 found in?
liver
pancreatic beta cells
what tissues are GLUT-3 found in?
esp. neurons
what tissues are GLUT-4 found in?
skeletal muscle
adipose tissue
how does the Na+- monosaccharide cotransporter system work?
needs energy
glucose moved into cell against the gradient
Na+ moved into cell w/ glucose with its gradient (from low to high)
where does the energy needed for the Na+ monosaccharide cotransporter system come from?
Na+, K+- ATPase (pumps sodium ions)
what are the transporters called that move glucose in the Na+ monosaccharide cotransporter system?
sodium-dependent- glucose- transporters
what are the 2 stages of glycolysis?
energy investment & energy generation
where is hexokinase found and what is the Km and Vmax (relatively)?
most tissues
Km- low
Vmax- low
where is glucokinase found and what is the Km and Vmax (relatively)?
liver/ pancreatic beta cells
Km- high
Vmax- high
how does the well fed state affect PFK-2 and thus PFK-1?
insulin dominant
PFK-2 is dephosphorylated and ACTIVE
F-2,6BP is made
PFK-1 is activated
how does the fasting state affect PFK-2 and thus PFK-1?
glucagon dominant
PFK-2 is phosphorylated and INACTIVE
F-2,6BP is not made
PFK-1 is not activated
when is pyruvate kinase active in the liver?
during well fed state
how is NAD+ regenerated in the aerobic state?
electron transport chain (pyruvate to acetyl CoA)
how is NAD+ regenerated in anaerobic state?
pyruvate is converted to lactate
lactate converted to NADH to NAD+
what enzyme coverts pyruvate in lactate?
lactate dehydrogenase
what are the 3 ways pyruvate can be used?
turned into lactate
the lactate can be converted back into pyruvate in the liver for gluconeogenesis
can be converted to oxaloacetate for gluconeogenesis
what is the NET energy yield of anaerobic glycolysis?
2 ATP/ glucose
what is the NET energy yield of aerobic glycolysis?
2 ATP/glucose
2 NADH/ glucose
what are the 3 key enzymes that are under hormonal regulation by the liver (aka insulin and glucagon)?
glucokinase
phosphofructokinase
pyruvate kinase
how does insulin and glucagon affect the key enzymes of glycolysis?
insulin stimulates
glucagon inhibits
what causes maturity onset diabetes of the young (MODY)?
mutations that reduce glucokinase
how does arsenic poisoning affect glycolysis?
arsenic competes w/ inorganic phosphate as a substrate for glyceraldehyde 3-P
if it wins, the ATP generation step will be skipped and the net energy will be 0
what part of the body does pyruvate kinase deficiency affect?
RBCs because they rely completely on glycolysis for energy
how can pyruvate kinase deficiency be distinguished from G6PD deficiency?
there are NO Heinz bodies in pyruvate kinase deficiency
