Glycolysis pt 2

fermentation

general term for processes that extract energy (as ATP) but do not consume oxygen or change the concentrations of NAD+ or NADH

lactic acid fermentation

• pyruvate accepts electrons from NADH and is reduced to lactate while regenerating the NAD+ necessary for glycolysis

• lactate is carried in blood to the liver, where it is converted to glucose during recovery 

ethanol (alcohol) fermentation

pyruvate is further catabolized to ethanol

• regenerates NAD+

lactate dehydrogenase

catalyzes the reduction of pyruvate to lactate

Hexokinase is inhibited by

the product, Glucose 6-Phosphate

Phosphofructokinase-1 regulation

• ATP inhibits PFK-1

• ADP and AMP allosterically relieve this inhibition by ATP 

fructose 2,6-bisphosphate regulationes

mediates the rapid hormonal regulation of glycolysis

binds to PFK-1 and increases its affinity for fructose 6-phosphate

Purpose of pentose phosphate

Nucleotides, coenzymes, DNA, RNA

Overall Equation for the Pentose Phosphate Pathway

glucose 6-phosphate + 2NADP⁺ + H₂O    →

ribulose 5-phosphate + CO₂ + 2NADPH + 2H⁺

Cells and Tissues That Use the Pentose Phosphate Pathway

• rapidly dividing cells

• tissues that carry out extensive fatty acid synthesis require the NADPH

• tissues that actively synthesize cholesterol and steroid hormones require the NADPH

Pentose phosphate steps