Lecture 15 - Glycolysis Flashcards
In glycolysis 1 molecule of […] is converted to 2 molecules of […] and generates 2 molecules of […].
Glucose; Pyruvate; ATP
Sources of glucose in diet.
Disaccharides (i.e. sucrose and lactose), starch, and glycogen.
Only fuel that RBCs can use.
Glucose
Pyruvate and lactate can be salvaged and resynthesized to glucose via […].
Gluconeogenesis
Protein transporters that uptake glucose.
Glucose transporters (GLUTs)
GLUT transporter, ubiquitous but expressed highly in brain and RBCs.
GLUT1
GLUT transporter, main transporter in liver.
GLUT2
GLUT transporter, main transporter in neurons.
GLUT3
GLUT transporter, present in skeletal muscle, heart, and adipose tissue.
GLUT4
GLUT transporter, has the low affinity.
GLUT2
GLUT transporters with high affinity.
GLUT1 and GLUT3
GLUT transporter that is regulated insulin.
GLUT4
Location of glycolysis.
Cytoplasm
Two stages of glycolysis.
Trapping of glucose and generation of ATP.
Step of glycolysis, traps glucose.
Glucose → Glucose-6-phosphate via hexokinase
Step of glycolysis, commited step.
Fructose-6-Phosphate → Fructose-1,6-Bisphosphate via phosphofructokinase (i.e. consumes ATP)
Enzymes in glycolysis, utilize ATP.
Hexokinase and phosphofructokinase
Rate limiting enzyme of glycolysis.
Phosphofructokinase
Enzyme of glycolysis, reduceds NAD+ to NADH.
GAPDH (i.e. NADH goes to ETC)
ATP producing steps of glycolysis.
1,3-Bisphosphoglycerate → 3-phosphoglycerate via phosphoglycerol kinase and phophoenolpyruvate → pyruvate via pyruvate kinase
Three fates of pyruvate produced in glycolysis.
Ethanol, lactate (i.e. regenerates NAD+), acetyl CoA (i.e. for further oxidation)
Disaccharide of glucose and fructose.
Sucrose
Disaccharide of glucose and galactose.
Lactose
Major regulatory enzymes of glycolysis.
Hexokinase, phosphofructokinase, and pyruvate kinase.
Enzyme of glycolysis, converts glucose to glucose-6-phosphate
Hexokinase
Enzyme of glycolysis, converts fructose-6-phosphate to fructose-1,6-bisphosphate.
Phosphofructosokinase
Enzyme of glycolysis, converts phophoenolpyruvate to pyruvate.
Pyruvate kinase
Goal of glycolysis in muscle.
To generate ATP during activity.
Regulator of glycolysis within muscle.
ATP
Goal of glycolysis within the liver.
To maintain blood lgucose levels, to provide building blocks for other pathways.
Significance of hexokinase not being present in the liver.
Prevents glucose from being permentantly trapped, uses glucokinase instead.
In the liver phosphofructukinase is activated via […] and inhibited via […].
Fructose-2,6-Biphosphate; citrate
How is pyruvate kinase regulated within the liver?
Allosteric effectors and covalent modification.
Main reason excess fructose consumption can lead to pathological conditions.
Fructose when metabolized bypasses the most important regulatory step of glycolysis (i.e. step catalyzed by phosphofructokinase)
Enzyme deficient in individuals with lactose intolerance.
Lactase
Term, disruption of galactose metabolism.
Galactosemia
Classic galactosemia is due to inherited deficiency in […] activity.
Galactose 1-phosphate uridyl transferase
Diagnostic of galactosemia.
Absences of galactose-1-phosphate uridyl transferase in RBCs
As a result of galactose 1-phosphate uridyl transferase cataracts can form. This is because the enzyme aldose reductase reduces galactose to […].
Galactitol
Process, when rapidly growing tumor cells metabolize glucose to lactate even in the presence of oxygen.
Aerobic glycolysis/Warburg effect
