Glycolysis, PPP, Cori Cycle

What are the products of glycolysis?

2 pyruvate, 2 ATP, 2 NADH

The anaerobic pathway of glycolysis produces _______ in animals

lactate

The anaerobic pathway of glycolysis produces _______ in yeast

ethanol

Aerobic pathway of cellular respiration

Glycolysis -> TCA -> ETC

Why does glucose get phosphorylated to glucose-6-phosphate?

So it cannot leave the cell

Glucose -> Glucose-6-phosphate catalyzed by

Hexokinase

Glucose-6-phosphate -> Fructose-6-phosphate catalyzed by

Phosphohexose isomerase

Fructose-6-phosphate -> Fructose-1,6-bisphosphate catalyzed by

Phosphofructokinase-1

Fructose-1,6-bisphosphate -> Glyceraldehyde-3-phosphate & dihydroxyacetone phosphate catalyzed by

Aldolase

Dihydroxyacetone phosphate -> Glyceraldehyde-3-phosphate catalyzed by

Triosephosphate isomerase

Glyceraldehyde-3-phosphate -> 1,3-bisphosphoglycerate catalyzed by

Glyceraldehyde-3-phosphate dehydrogenase

1,3-bisphosphoglycerate -> 3-phosphoglycerate catalyzed by

Phosphoglycerate kinase

3-phosphoglycerate -> 2-phosphoglycerate catalyzed by

Phosphoglycerate mutase

2-phosphoglycerate -> phosphoenolpyruvate catalyzed by

Enolase

Phosphoenolpyruvate -> pyruvate catalyzed by

Pyruvate kinase

Order of Glycolysis

What are the control points of glycolysis?

Step 1: Glucose -> Glucose-6-phosphate

Step 3: Fructose-6-phosphate -> Fructose-1,6-bisphosphate

Step 10: Phosphoenolpyruvate -> Pyruvate

What is the step that commits glucose to glycolysis and what enzyme catalyzes it?

Fructose-6-phosphate -> Fructose-1,6-bisphosphate

Phosphofructokinase-1

What does ketoacidosis do?

Decrease blood pH

What are the biproducts of fatty acid oxidation?

Acetoacetate & β-hydroxybutyrate

Insulin is released by what kind of cells?

pancreatic β cells

What does lactate dehydrogenase do?

converts pyruvate to lactate

it allows glycolysis to continue producing ATP in the absence of oxygen but does not affect the glycolytic pathway

What enzyme catalyzes the conversion of pyruvate to ethanol during alcohol fermentation?

alcohol dehydrogenase

What is fetal alcohol syndrome?

ethanol is broken down to acetaldehyde; high levels of acetaldehyde can cross the placenta and accumulate in fetal liver

What is beriberi?

Thiamine deficiency that causes neurological issues and other symptoms

Found in people that are alcoholics but don't eat

What is gluconeogenesis?

Making glucose from a non-carbohydrate source

It is not the reverse of glycolysis

What is the pentose phosphate pathway?

It makes NADPH and pentose sugars with phosphate group

What do the oxidative reactions of the pentose phosphate pathway produce?

NADPH

What do the non-oxidative reactions of the pentose phosphate pathway produce?

5 carbon sugars (specifically ribose-5-phosphate)

What inhibits phosphofructokinase?

High concentrations of ATP

What activates phosphofructokinase?

High concentrations of AMP

Gluconeogenesis steps that replace glycolysis control points

1. Glucose-6-phosphate -> Glucose is catalyzed by Glucose-6-phosphatase

3. Fructose-1,6-bisphosphate -> Fructose-6-phosphate is catalyzed by Fructose-bis-phosphate phosphatase

10. Pyruvate -> Phosphoenolpyruvate happens in 2 steps

Step 1: Pyruvate -> Oxaloacetate is catalyzed by pyruvate carboxylase

Step 2: Oxaloacetate -> Phosphoenolpyruvate is catalyzed by phosphoenolpyruvate carboxykinase

Oxaloacetate is an intermediate that is not present in glycolysis but is in gluconeogenesis

What is TPP (Vitamin B1)?

A key factor in decarboxylation reactions

ex: pyruvate carboxylase catalyzes pyruvate -> oxaloacetate

What is the Cori Cycle?

Regulates blood glucose levels and provides a mechanism to recycle lactate produced by muscles

Where are GLUT1 and GLUT2 transporters found?

hepatocytes (liver cells)

Where are GLUT3 transporters found?

Brain neurons

Where are GLUT4 transporters found?

skeletal muscle, cardiac muscle, adipocytes

What do disaccharidases do?

break down disaccharides into monosaccharides