Biological Molecules Part One

For this section of biology, you need to know the different types of bonding between atoms, This is mainly seen in chemistry but also links heavily to this section of biology,

Covalent Bonds – Atoms share a pair of electrons in their outer shell meaning that the outer shell is full and the molecule becomes more
stable. A common example of this bond is CO2 (carbon dioxide)

Ionic Bonds – Ions with opposite charges are attracted to each other forming a bond. Example: NaCl

Hydrogen Bonds – The electrons within a molecule are not evenly distributed but spend more time in one position, this region becomes more
negatively charged than the rest of the molecule. A molecule with an uneven distribution of charge is said to be ‘polar’.
The most common example of a polar molecule is H2O (water)

You also need to know about the different parts of polymerization reactions.

Condensation Reaction – Molecules are joined together to form a polymer with water (H2O) released as a product

Hydrolysis – Water (H2O) is used to separate a polymer into monomers

Condensation reactions and hydrolysis is reversible, for example; Nucleotides can for polynucleotides (nucleic acid) through a condensation reaction, polynucleotides can be returned back to nucleotides through hydrolysis. The same can happen between glycerol and lipids, monosaccharides and polysaccharides (carbohydrates), fatty acids and lipids, and amino acids and polypeptides (proteins)