Glycolysis
The conversion of glucose to pyruvate
Purpose:
- oxidize glucose to obtain energy (other sugars)
- Make ATP by substrate-level phosphorylation •anaerobic pathway
Starting materials:
- Glucose
- 2ATP
- 2NAD+
Products:
- 2 pyruvate
- 4 ATP
- 2 NADH
Energy sources for humans
- Carbohydrates major source of energy
- Glucose preferred source of energy (Central molecule for metabolism)
Fate of pyruvate
- oxidation to acetyl-CoA (most common): aerobic
- reduction to to lactate (muscles): anaerobic
- conversions to glucose (liver)
- converted to ethanol (in yeast)
Purpose of lactate fermentation..
Regenerate NAD+ under anaerobic conditions (recycle)
Glycolysis produces…
- 2 ATP by substrate-level phosphorylation
- NADH
- pyruvate
Pentose phosphate pathway
_Purpose: _
- synthesize ribose
- synthesize NADPH
- power biosynthesis
- regenerate glutathione for ROS protection
Recycles:
Vitamin E< vitamin C< glutathime< NADPH
Glycogenisis
Pathway that puts glucose into storage (Creation)
- when blood concentrations are high
- requires energy
Glycogenolysis
Pathway that takes glucose out of storage (hydrolysis)
- In the liver when blood glucose is low
Insulin
Causes glucose to be removed from blood and stored in glycogen
- Glucose⇒glycogen (glycogenesis)
Glucogon
- Causes the release of glucose back into the blood Glycogen⇒glucose (glycogenolysis)
- [epinephrine has the same effect/increased blood sugar]
Gluconeogenesis
Synthesis of new glucose occurs in the liver during times of high demand for glucose (energy expensive)
Purpose:
- synthesize glucose
Starting material:
- pyruvate & CO2
Products:
- glucose
Cori cycle
- Removes lactate
- provides extra glucose
Energy source in muscle cells:
Glycogen
- creating phosphate use to supply energy during peak demand
Effect of starvation
Molecules that are used:
- Glycogen
- Pyruvate
- lactate
- amino acids
pyruvate
Glucose metabolism
