1. Biological Molecules
‘what you need to know!’

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

3. MONOMER
POLYMERISATION
POLYMER

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

5. CARBOHYDRATES

6. CARBOHYDRATES
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 – C6H12O6 or C3H6O3 or C5H10O5
Structural
formula –

11. Triose or Pentose or Hexose
C6H12O C3H6O C5H10O5
You decide!

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

13. Carbon C6
H12
Hydrogen O6
Oxygen

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

15. 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. Structural Isomers Both these molecules are glucose.
Both have a molecular formula of C6H12O6.
But they are structurally different and will have
different functions in a cell.

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
Two  glucose molecules meet.
The OH from C1 & H from C4 react.
Water is expelled. This is called a condensation reaction.
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
STARCH
CELLULOSE
GLYCOGEN

20. Starch Polymer of glucose. Plant storage polysaccharide.
Made up of two types of substances;
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. 1-6 links form a branch
structure
1-4 links form a helical
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 180o.
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.