Carbohydrates

CARBOHYDRATES

CARBOHYDRATES

1. Monosaccharides.

2. Disaccharides.

3. Polysaccharides.

CARBOHYDRATES
1. MONOSACCHARIDES:

( PENTOSES, HEXOSES )

Pentoses (5-carbon compounds):
Ribose, Deoxy-Ribose.


Hexoses (6-carbon compounds):
Glucose, Fructose, Galactose.

CARBOHYDRATES

2. DISACCHARIDES:

Maltose, Isomaltose, Lactose, Succrose.

3. POLYSACCHARIDES:
Starch-plant source, straight-chain of glucose
molecules
Glycogene-animal source, branched chain of glucose molecules

Digestion & absorption of carbohydrates

Mouth:
salivary amylase converts polysaccharides into smaller saccharides.

Doudenum:

pancreatic amylase converts polysaccharides (starch, glycogene) into maltose, isomaltose.

Small intestine: Disaccharides are digested and absorbed.

Maltose two Glucose molecules Isomaltose two Glucose molecules
Succrose Glucose + Fructose
Lactose Glucose + Galactose


Glucose, fructose and galactose are absorbed by small intestine by active process (ATP) into portal circulation leading to increased blood glucose level there, which stimulate β-cells of Langerhans to release insulin.

Insulin increases the entry of glucose into cells, therefore, controlling the normal glucose level between

(60-110 mg/dl)

(3.5-6.1 mmol/L)

glucose

glucose-6-phosphate (station compound)

Glycolysis pentose phosphate

pathway

Glycogene synthesis

Glucose -6- phosphate ( station compound )

Types of reactions

• Irreversable reaction
• usually needs kinase enzyme
• usually there is a loss of ATP mol
• ATP ADP + Pi
• formation of essential product
• a reaction could be irreversable by a specific enzymes producing essensial product
• phenyl alanine PAH Tyrsonine


2. Reversable
the lot need ATP
there is interconversion between the reactant and its product