Carbohydrate is branched into 3 - monosaccharide, disaccharide, polysaccharide. Monosaccharide and polysaccharide are soluble, but polysaccharide is unsoluble
Monosaccharide is the simplest sugar which is usually glucose. Glucose is used for cellular respiration. Glucose is also a major nutrients for cells.
Disaccharide is made of two monosaccharide joined together by glycosidic bond via condensation reaction.
Polysaccharide is the complex carbohydrate. Four examples of polysaccharide ; starch, glycogen, cellulose, and chitin.
Starch is divided into amylose and amylopectin. Plant store starch as granules in Plastids, includes chloroplast. Synthesizing starch will enable the plant to store stockpile surplus glucose. Humans have enzyme that can hydrolyse starch into glucose.
Amylose is unbranched and is a long straight polypeptide. Glucose is released from each end of amylose. It has 1,4 glycosidic bond.
Amylopectin is branched polymer. It has many terminals. Glucose is released more rapidly because of the branched polymer. It has 1,4 and 1,6 glycosidic bond.
Glycogen has similarity to amylopectin, but it has more branches than amylopectin, hence will release glucose more rapid. It has 1,6 glycosidic bond. Glycogen is stored in the liver and muscle cells. When our body is demanding sugar, glycogen will be hydrolysed into glucose to fulfill the demand. However it cannot sustain our body for long. Glycogen stores will be depleted in about a day unless be replenished by consumption of food.
Cellulose is a straight polymer. The parallel cellulose which are held together is called, microfibril. Cellulose is the major component of plant cell wall. Microfibril are strong materials for plants such as woods. Cellulose cannot be digested by human. However, there are some organism that can digest cellulose. Cow has an bacteria which can digest cellulose in its first compartment which is rumen. Termites can digest cellulose, by having microbes living in its gut which can hydrolyse cellulose. That is why termites can eat woods.
Cellulose cannot be digested by our body. However it can avoid us from constipation. Cellulose will abrades the wall of digestive tracts to produce mucus along the lining which aids the passage of foods.
Chitin is to form the exoskeleton for arthropods. Pure chitin is leathery but it is harden by calcium carbonates. Structure of chitin is the same as cellulose, except chitin has nitrogen containing appendage.
Done with my revision for carbohydrates. Alhamdulillah.
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