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Biological Molecules ‘what you need to know!’. MONOMER – single repeating units that…… ……are joined together to form POLYMER.

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Presentation on theme: "Biological Molecules ‘what you need to know!’. MONOMER – single repeating units that…… ……are joined together to form POLYMER."— Presentation transcript:

1 Biological Molecules ‘what you need to know!’

2 MONOMER – single repeating units that…… ……are joined together to form POLYMER.

3 POLYMER MONOMER POLYMERISATION

4 Polymers Polysaccahrides Proteins Lipids? Monomers Glucose Amino acids Glycerol & fatty acids

5 CARBOHYDRATES

6 MONOSACCHARIDES DISACCHARIDES POLYSACCHARIDES

7 MONOSACCHARIDES - A single sugar unit - Sweet and soluble - Contain carbon, hydrogen & oxygen - Classified according to the number of carbons a molecule has.

8 MONOSACCHARIDES TRIOSE – 3 carbons PENTOSE – 5 carbons HEXOSE – 6 carbons

9 MONOSACCHARIDES – which is which?

10 MONOSACCHARIDES – which formula? Molecular formula – C 6 H 12 O 6 or C 3 H 6 O 3 or C 5 H 10 O 5 Structural formula –

11 C 6 H 12 O 6 C 3 H 6 O 3 C 5 H 10 O 5 You decide! Triose or Pentose or Hexose

12 Pentose and hexose sugars exist in two forms: Straight chain forms Ring forms

13 Hydrogen Carbon Oxygen C6C6 H 12 O6O6

14 GLUCOSE comes in 2 forms, according how the ring closes. For example, this one: this H is above Here this H is above the carbon. This is called  (alpha) glucose.

15 this H is below Here this H is below the carbon. This is called β (beta) glucose. WARNING! A single detail like this one makes all the difference. The position of the OH group on C1 will determine the type of polysaccharide it will form and in turn, the functions it will have in a cell.

16 Both these molecules are glucose. Both have a molecular formula of C 6 H 12 O 6. But they are structurally different and will have different functions in a cell. Structural Isomers

17 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

18 Forming a disaccharide… …MALTOSE 1.Two  glucose molecules meet. 2.The OH from C1 & H from C4 react. 3.Water is expelled. This is called a condensation reaction. 4.The bond between the two joined glucoses is called glycosidic bond.

19 Polysaccharides Polymers with subunits of monosaccharides Repeated condensation reactions Normally thousands of monomers long Polysaccharides are not sugars STARCHCELLULOSEGLYCOGEN

20 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.

21 Spiral structure of amylose; part of starch.

22 Amylopectin Condensation reactions between α glucose (1-4 links). Branches of 1-6 links also exist. Coiled springs with a branched structure are formed.

23 1-4 links form a helical structure 1-6 links form a branch structure

24 Amylopectin Mostly 1-4 links. Some 1-6 links.

25 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.

26 GLYCOGEN is the storage polysaccharide in animals It has 1-4 links and 1-6 links

27 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

28 Cellulose C1-4 links make up this polysaccharide. If C1 and C4 are to react, one glucose molecule needs to flip through 180 o. It is this subtle difference that make cellulose so strong! This structure has H bonds holding the parallel chains together

29 70 chains of β glucose combine to form a MICROFIBRIL. Lots of MICROFIBRILS are held together to form FIBRES.


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