It is often known as sugars or simple sugars which serves as food reserves in animals and plants. Carbohydrates are important main energy source for various metabolic activities to be done. It is an organic compound composed of carbon, hydrogen and oxygen.
Below are the general structure of carbohydrates:
Below are the general structure of carbohydrates:
There are three classes:
1. Monosaccharides (simple sugar)
: main / major respiratory substrate
: creates high osmotic pressure in plant cells
Examples :
glucose, ribose, galactose, fructose
2. Disaccharides/ Oligosachharides
: soluble in water
: maltose - used in brewing beer
: sucrose - form of carbohydrate that is generally transported from leaves to other photosynthetic organs
3. Polysaccharides
2. structural polysachharides (cellulose and chitin)
Starch
2. amylopectin - complex form, highly branched polymer, linear chain
Glycogen
Cellulose
most animals do not possesses enzymes that can hydrolyze beta linkages of cellulose
Chitin
1. Monosaccharides (simple sugar)
- general formula - (CH20)n
- monomer - glucose
- contains - aldehyde group (-CH0)
- characteristics : sweet, soluble in water, can be crystallized, undergoes condensation to form disachharide / polysachharide, are reducing sugar
- functions : raw material for the synthesis of disaccharides / polysachharides
: main / major respiratory substrate
: creates high osmotic pressure in plant cells
Examples :
glucose, ribose, galactose, fructose
2. Disaccharides/ Oligosachharides
- general formula - C12H22O11
- form when two monosachharides joined by a glycosidic linkage, a covalent bond through condensation/ dehydration (removal of water)
- characteristics : small, sweet
: soluble in water
: maltose - used in brewing beer
: sucrose - form of carbohydrate that is generally transported from leaves to other photosynthetic organs
- 3 common disaccharides
- maltose (a-glucose + a-glucose)
- sucrose ( glucose +fructose)
- lactose (galactose + glucose)
3. Polysaccharides
- macromolecules, polymer with few hundred to a few thousand monosachharides joined by glycosidic linkages
- different forms of polysachharides
2. structural polysachharides (cellulose and chitin)
Starch
- plants storage polysachharides
- polymer formed by alpha glucose joined by1-4 glycosidic linkage
- polymer of glucose
- two types of starch
2. amylopectin - complex form, highly branched polymer, linear chain
Glycogen
- shorter chains and highly branched
- stored in liver and muscle cells
- storage polysaccharides in animals, energy provider, excellent storage compound, insoluble in water, doest not increase osmotic pressure, cannot be crystallized
Cellulose
- acts as structural support to cell walls of plants, main component of cell wall
most animals do not possesses enzymes that can hydrolyze beta linkages of cellulose
Chitin
- act as main component of fungi cell walls, the exoskeletons (hard outer shell/skin) of arthropods
- microorganisms, such as bacteria and fungi secrete chitinases, which over time can break down chitin