Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Biological Molecules ‘what you need to know!’ MONOMER – single repeating units that…… ……are joined together to form POLYMER. MONOMER POLYMERISATION POLYMER Polymers Monomers Polysaccahrides Glucose etc. Proteins Amino acids Lipids Glycerol & fatty acids CARBOHYDRATES CARBOHYDRATES MONOSACCAHRIDES DISACCAHRIDES POLYSACCAHRIDES MONOSACCHARIDES - A single sugar unit - Sweet and soluble - Contain carbon, hydrogen & oxygen - Classified according to the number of carbons a molecule has. MONOSACCHARIDES TRIOSE – 3 carbons PENTOSE – 5 carbons HEXOSE – 6 carbons MONOSACCHARIDES – which is which? MONOSACCHARIDES – which formula? Molecular formula – C6H12O6 or C3H12O6 or C5H10O5 Structural formula – Triose or Pentose or Hexose C6H12O6 C3H12O6 You decide! C5H10O5 Straight chain forms Pentose and hexose sugars exist in two forms: Ring forms Carbon Hydrogen Oxygen C6H12O6 GLUCOSE comes in 2 forms, this one; Here this H is above the carbon. This is called α (alpha) glucose. Here this H is below the carbon. This is called β (beta) glucose. Structural Isomers Both these molecules are glucose. Both have a molecular formula of C6H12O6. But they are structurally different. Biological role of monosaccharides As an energy source….. •A large amount of energy is stored between the C-H bonds •This is released to form ATP •ATP is the energy currency of the cell As building blocks….. •Repeated glucose molecules build up; starch & glycogen •Ribose (5C) forms part RNA •Deoxyribose (5C) forms part DNA Forming a disaccharide… …MALTOSE Two α glucose molecules C1 & C4 meet. OH (hydroxl grp) from C1 & H from C4 react. Water is expelled. A condensation reaction. This can be reversed by adding water. Polysaccharides • Polymers with subunits of monosaccharides • Repeated condensation reactions • Normally 1000’s of monomers • Polysaccharides are not sugars STARCH CELLULOSE GLYCOGEN Starch • Polymer of glucose. • Plant storage polysaccharide. • Made up of two types of substances; 1)Amylose 2) Amylopectin Amylose • Condensation reactions between α glucose (1-4 links). • Forms from 1000s of condensation reactions. • Coiled springs are formed. Spiral structure of amylose; part of starch. Starch Made up of two types of substances; 1)Amylose 2) Amylopectin Amylopectin • Condensation reactions between α glucose (1-4 links). • Branches of 1-6 links also exist. • Coiled springs with a branched structure are formed. 1-6 links form a branch structure 1-4 links form a helical structure Amylopectin Mostly 1-4 links. Some 1-6 links. Starch grains are a mixture of amylose & amylopectin Starch is a polysaccharide Starch it is a insoluble store of glucose Starch is only found in plant cells, the animal equivalent is called GLYCOGEN. GLYCOGEN is the storage polysaccharide in animals It has 1-4 links and 1-6 links Cellulose • Present in plant cell walls. • Has a slow decomposition. • It is the most abundant organic molecule on the planet!! • It is mechanically very strong. • It is a polymer of β glucose Cellulose • C1-4 links make up this polysaccharide. • If C1 and C4 are to react, one glucose molecule needs to flip through 180o. • It is this subtle difference that make cellulose so strong! • This structure has H bonds holding it together 70 chains of β glucose combine to form a MICROFIBRIL. Lots of MICROFIBRILS are held together to form FIBRES.