Glycolysis Flashcards
Glucose –> Glucose-6-phosphate
Start: Glucose
End: G6P
Enzymes: Hexokinase/Glucokinase
In the liver glucokinase removes glucose from the _____
hepatic portal vein (due to glucokinase, the liver does not need insulin)
In the _____ glucokinase stimulates ____ secretion along with calcium
Pancreas; insulin
Glucose-6-Phosphate → Fructose-6-Phosphate
Starting Compound: Glucose-6-phosphate
Ending Compound: Fructose-6-phosphate
Enzyme: Phosphohexose Isomerase
Isomers
Fructose-6-Phosphate → Fructose 1, 6-bisphosphate
Starting Compound: Fructose-6-phosphate
Ending Compound: Fructose 1, 6-bisphosphate
Enzyme: Phosphofructokinase
Requires ATP
Fructose 1, 6-bisphosphate → Dihydroxyacetone Phosphate + Glyceraldehyde-3-phosphate
Starting Compound: Fructose 1, 6-bisphosphate
Ending Compounds: Dihydroxyacetone Phosphate + Glyceraldehyde-3-phosphate
Enzyme: Aldolase
Dihydroxyacetone Phosphate → Glyceraldehyde-3 phosphate
Starting Compound: Dihydroxyacetone Phosphate
Ending Compounds: Glyceraldehyde-3 phosphate
Enzyme: Triose Phosphate Isomerase
Gyceraldehyde-3 phosphate → Bisphosphoglycerate
Starting Compound: Gyceraldehyde-3 phosphate
Ending Compounds: Bisphosphoglycerate
Enzyme: Glyceraldehyde-3-phosphate dehydrogenase
Bisphosphoglycerate → 3-Phosphoglycerate
Starting Compound: Bisphosphoglycerate
Ending Compound: 3-Phosphoglycerate
Enzyme: Phosphoglycerate Kinase
ATP formed
3-Phosphoglycerate → 2-Phosphoglycerate
Starting Compound: 3-Phosphoglycerate
Ending Compounds: 2-Phosphoglycerate
Enzyme: Phosphoglyceromutase
2-Phosphoglycerate → Phosphoenolpyruvate
Starting Compound: 2-Phosphoglycerate
Ending Compounds: Phosphoenolpyruvate
Enzyme: Enolase
Phosphoenolpyruvate → Pyruvate
Starting Compound: Phosphoenolpyruvate
Ending Compounds: Pyruvate
Enzyme: Pyruvate Kinase
ATP Formed
5 Tissues Producing Lactate under Anaerobic Conditions (Downing (anaerobic) on the SMS. RBG)
Skin
Skeletal Muscle
Retina
Brain
GI Tract
Describe the three irreversible reactions of glycolysis.
a. Hexokinase
b. Phosphofructokinase
c. Pyruvate Kinase
Explain the connection between glycolysis and the TCA cycle.
Pyruvate made in the cytosol (via glycolysis)
travels in mitochondria (where TCA cycle takes place) and
becomes acetyl-coA via pyruvate dehydrogenase complex.
Increased_____ (makes acetyl-CoA) decreases _____ and pyruvate dehydrogenase complex (end products inhibit the cycle from continuing
Beta oxidation; glycolysis
Describe the possible connection between fructose consumption and development of obesity
Fructose bypasses hexokinase/glucokinase and phosphofructokinase (irreversible reactions) (glycolysis not as regulated)
i. This leads to quicker metabolism of fructose and more acetyl-CoA & pyruvate production.
Which then promotes lipogenesis (fat synthesis, leading to weight gain and potentially obesity)
Lactic Acidosis
i. Impaired activity of pyruvate dehydrogenase (needs thiamin as a co-enzyme) (can be caused by alcoholism or inherited pyruvate dehydrogenase deficiency)
Converts pyruvate to acetyl-coA
Without thiamin, pyruvate accumulates and converts to lactate.
Muscle Phosphofructokinase
i. Phosphofructokinase needed to convert fructose-6-phosphate → fructose 1,6-bisphosphate.
ii. Lipids can be used as alternative fuel source.
Hemolytic Anemia
i. Inherited aldolase A and pyruvate kinase deficiency.
ii. Aldolase A needed to convert fructose 1,6-bisphosphate → dihydroxyacetone phosphate OR glyceraldehyde-3-phosphate.
iii. Pyruvate Kinase is needed to convert phosphoenolpyruvate → Pyruvate.
Pyruvate Kinase Purpose
Catabolism of phosphoenolpyruvate to form pyruvate
RBCs unable to complete glycolysis (hemolytic anemia)
- abnormal, premature destruction by spleen
- destroyed RBC = bilirubin release = jaundice
- severe anemia = enlarges spleen
