Biological Moleculescbh

7/30/2019 Biological Moleculescbh

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Biological Molecules

what you need to know!


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MONOMER single repeating

units that

are joined together to form

POLYMER.


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POLYMER

MONOMER

POLYMERISATION


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Polymers

Polysaccahrides

Proteins

Lipids

Monomers

Glucose etc.

Amino acids

Glycerol &fatty acids


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CARBOHYDRATES


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CARBOHYDRATES

MONOSACCAHRIDES

DISACCAHRIDES

POLYSACCAHRIDES


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MONOSACCHARIDES

- A single sugar unit

- Sweet and soluble

- Contain carbon, hydrogen & oxygen

- Classified according to the number ofcarbons a molecule has.


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MONOSACCHARIDES

TRIOSE 3 carbons

PENTOSE 5 carbons

HEXOSE 6 carbons


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MONOSACCHARIDES which is which?


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MONOSACCHARIDES which formula?

Molecular formula C6H12O6 orC3H12O6

orC5H10O5

Structural

formula


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C6H12O6 C3H12O6 C5H10O5

You decide!

Triose or Pentose or Hexose


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Pentose and hexose sugars

exist in two forms:

Straight chain forms

Ring forms


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Hydrogen

Carbon

OxygenC6H12O6


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GLUCOSE comes in 2forms, this one;

Here this H is abovethe carbon.

This is called (alpha)

glucose.


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Here this H is belowthe carbon.

This is called

(beta) glucose.


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Both these molecules are glucose.

Both have a molecular formula of C6H12O6.

But they are structurally different.

Structural Isomers


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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 ATPATP is the energy currency of the cell

As building blocks..Repeated glucose molecules build up; starch & glycogenRibose (5C) forms part RNA

Deoxyribose (5C) forms part DNA


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Forming a disaccharideMALTOSE

Two 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.


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Polysaccharides

Polymers with subunits of monosaccharides Repeated condensation reactionsNormally 1000s of monomers

Polysaccharides are not sugars

STARCH CELLULOSE GLYCOGEN


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Starch Polymer of glucose.

Plant storage polysaccharide. Made up of two types of substances;1)Amylose 2) Amylopectin

Amylose Condensation reactions betweenglucose(1-4 links).

Forms from 1000s of condensation reactions.

Coiled springs are formed.


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Spiral structure ofamylose; part of starch.


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StarchMade up of two types of substances;

1)Amylose 2) Amylopectin

Amylopectin

Condensation reactions betweenglucose(1-4 links).

Branches of 1-6 links also exist.

Coiled springs with a branched structure areformed.


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1-4 links form a helical

structure

1-6 links form a branch

structure


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Amylopectin

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


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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 animalequivalent is called GLYCOGEN.


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GLYCOGEN is the storagepolysaccharide in animals

It has 1-4 links

and 1-6 links


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Cellulose

Present in plant cell walls.

Has a slow decomposition.

It is the most abundant organic molecule onthe planet!!

It is mechanically very strong.

It is a polymer of glucose

C ll l


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Cellulose

C1-4 links make up this polysaccharide.

If C1 and C4 are to react, one glucosemolecule needs to flip through 180o.

It is this subtle difference that makecellulose so strong!

This structure has H bonds holding ittogether


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70 chains of glucose combine to form aMICROFIBRIL.

Lots of MICROFIBRILS are held together to form

FIBRES

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Biological Moleculescbh