Transcript Launch Activity

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.