Biological Molecules

Living Things

80% of a living organism is water

13% is organic marcromolecukes

• Carbohydrates
• Proteins
• Lipids
• Nucleic acids

7% is non-organic molecules

• Vitamins

Carbon:

• Readily forms bonds with other carbons
• Forms a backbone for other carbons to attach to

Carbohydrates only contain: Carbon, Hydrogen and Oxygen.

Carbohydrates ------> Sugars -------> Monosaccharides {Glucose, Fructose, Galactose}

                                               --------> Disaccharides {Maltose, Sucrose, Lactose}

                         ------> Polysaccharides {Starch, Glycogen, Cellulose}

• Disaccharides are formed when 2 monosaccharides join together
• The reaction forms a water molecule so it is known as a condensation reaction
• The type of bond formed is called a glycosidic bond
• The opposite of a condensation reaction is a hydrolysis reaction

Maltose = Glucose + glucose

Lactose = Glucose + galactose

Sucrose = Glucose + fructose

• Two glucose molecules C1 and C4 meet
• OH (Hydroxyl group) from C1 and H from C4 react
• Water is expelled

Polysaccharides are polymers with subunits of monosaccharides They are NOT sugars

Starch:

• Plant Storage polysaccharides
• Made up of amylase and amylopectin

Amylase:

• Condensation reaction between alpha glucose forms 1000s of condensation reactions. 
• Coiled springs are formed

Amylopectin:

• Condensation reaction between Glucose 1-4 links
• 1-6 branches also exist

A storage molecule needs to be big so that they are not soluble, they need to be coiled to fit lots in a small area.Storage structures are branched because it makes them stronger.

• Storage polysaccharide in animals. Found in the liver and muscle cells where a store of energy is needed. Many fungi also store glycogen.
• More branched than starch as animals need more energy - it is easier to break the glycogen apart when it is branched.
• Forms tiny granules inside cells which are usually associated with the smooth endoplasmic reticulem.
• Each glycogen contains a few thousand glucose links.

• Cellulose is found in the cell wall of plants.

• It is the most abundant organic molecule.

• It is mechanically very strong.

• It is a polymer of Beta glucose.

• This structure has H bonds holding it together. They are relitavely weak.

• If C1 and C4 are to react, 1 glucose has to flip 180 degrees.