Carbohydrate Structure

Study Notes

Monosaccharides: simplest form of carbohydrates, composed of 3-7 carbon atoms
- Examples: glucose, fructose, galactose
- Classified as aldoses (have an aldehyde group) or ketoses (have a ketone group)
Disaccharides: formed by condensation reaction between two monosaccharides
- Examples: sucrose (glucose + fructose), lactose (glucose + galactose)
Polysaccharides: formed by condensation reaction between multiple monosaccharides
- Examples: starch (glucose polymers), cellulose (glucose polymers), glycogen (glucose polymers)

Glycolysis: breakdown of glucose to pyruvate, occurring in cytosol
- Generates ATP and NADH
- Can occur anaerobically (without oxygen) or aerobically (with oxygen)
Gluconeogenesis: synthesis of glucose from non-carbohydrate sources (e.g. amino acids, lactate)
- Occurs in liver and kidneys
- Reverses glycolysis pathway
Glycogenolysis: breakdown of glycogen to glucose
- Occurs in liver and muscles
- Regulated by hormones (e.g. insulin, glucagon)
Pentose Phosphate Pathway: generates NADPH and pentoses from glucose
- Occurs in cytosol
- Important for nucleic acid synthesis and antioxidant defenses

Insulin: hormone that promotes glucose uptake and storage
- Released by pancreas in response to high blood glucose
- Stimulates glycogen synthesis and inhibits glycogenolysis
Glucagon: hormone that promotes glucose release and breakdown
- Released by pancreas in response to low blood glucose
- Stimulates glycogenolysis and inhibits glycogen synthesis
Other regulators: cortisol, thyroxine, and epinephrine also play roles in regulating carbohydrate metabolism

Monosaccharides are the simplest form of carbohydrates, composed of 3-7 carbon atoms.
Examples of monosaccharides include glucose, fructose, and galactose.
Monosaccharides are classified as aldoses (having an aldehyde group) or ketoses (having a ketone group).

Disaccharides are formed by a condensation reaction between two monosaccharides.
Examples of disaccharides include sucrose (glucose + fructose) and lactose (glucose + galactose).
Polysaccharides are formed by a condensation reaction between multiple monosaccharides.
Examples of polysaccharides include starch (glucose polymers), cellulose (glucose polymers), and glycogen (glucose polymers).

Glycolysis is the breakdown of glucose to pyruvate, occurring in the cytosol.
Glycolysis generates ATP and NADH.
Glycolysis can occur anaerobically (without oxygen) or aerobically (with oxygen).
Gluconeogenesis is the synthesis of glucose from non-carbohydrate sources (e.g. amino acids, lactate).
Gluconeogenesis occurs in the liver and kidneys.
Gluconeogenesis reverses the glycolysis pathway.
Glycogenolysis is the breakdown of glycogen to glucose.
Glycogenolysis occurs in the liver and muscles.
Glycogenolysis is regulated by hormones (e.g. insulin, glucagon).
The Pentose Phosphate Pathway generates NADPH and pentoses from glucose.
The Pentose Phosphate Pathway occurs in the cytosol.
The Pentose Phosphate Pathway is important for nucleic acid synthesis and antioxidant defenses.

Insulin is a hormone that promotes glucose uptake and storage.
Insulin is released by the pancreas in response to high blood glucose.
Insulin stimulates glycogen synthesis and inhibits glycogenolysis.
Glucagon is a hormone that promotes glucose release and breakdown.
Glucagon is released by the pancreas in response to low blood glucose.
Glucagon stimulates glycogenolysis and inhibits glycogen synthesis.
Other regulators such as cortisol, thyroxine, and epinephrine also play roles in regulating carbohydrate metabolism.