Carbohydrates are made from monosaccharides. Glucose is a monosaccharide found in two forms, a and b. Condesation reactions join monosaccharides together, water is removed and a glycosidic bond is formed.
Polysaccharides are lots of monosaccharides joined together.
Starch - the main energy storage in plants. Starch is a mixture of two polysaccharides. Amylose is a long unbranched chain of A glucose, the angles of the glyosidic bonds give a coiled structure which makes it compact to store lots in a small space.
Amylopectin - is made up of long branched chains of A glucose. The side branches allow the enzymes that break down the glycosidic bonds to get to them easily to release glucose faster.
Starch is also insoluble in water so lots can be stored in one place without altering the water potential so no water enters by osmosis.
Glycogen - is the storage material in animals. It has a lot of side branches so it can be released quickly and it is compact so good for storage.
Cellulose - is the major components in cell walls. It's made up of long unbranched chains of B glucose. The bonds between the sugars are straight and the separate chains are held together by hydrogen bonds forming microfibrils which provide structural support.
Animal and Plant Cells
- Plama Membrane - controls what enters and leaves the cell.
- Cytoplasm - where most chemical reactions happen, contains enzymes.
- Nucleus - stores genetic information and controls the cell.
- Mitochondria - where most respiration takes place.
- Ribosomes - where proteins are made.
Plant cells contain the same but extra components:
- Cellulose cell wall - support and strenght.
- Permanent vacuole - contains cell sap, a weak solution of sugar and salts.
- Chloroplasts - where photosynthesis occurs, they contain a green substance called chlorophyll.