Chemical bonds are linkages between two or more atoms that together form
molecules of compounds. One of these types of bond is hydrogen bond. Hydrogen
bonds are classified as weak bonds because they form and break easily and rapidly,
although together they are very strong. Hydrogen bonds are present in water and
help hold water molecules together because water is dipolar. Hydrogen bonding
attracts water to remain liquid at room temperature which is unexpected because
molecules with similar size are gases at room temperature. This allows organisms to
live in water, as well as a high specific heat capacity due to hydrogen bonding in
water as it ensures a stable environmental temperature as the water does not heat
up or cool down too quickly. Hydrogen bonds hold water molecules together,
therefore giving water the properties of cohesion and adhesion. Water molecules
would move faster and more rapidly without the presence of hydrogen bonds, like a
gas through which life does not exist on Earth.
Another type of bond present is the phosphodiester bond ( in DNA- semi
conservative replication). The two nucleotides join to form a dinucleotide phosphate
and the sugar forms a phosphodiester bond. This bond is a key structural feature of
the backbone of DNA and RNA and connects the 3’ carbon of a nucleotide to the 5’
Carbon of another to form the strands of DNA and RNA. The phosphodiester binding
is important for the maintenance of the structural stability of the nucleic acids. DNA
and RNA differ in structure as DNA is a double stranded ladder like molecule while
RNA is a single stranded molecule. However, both structures have a sugar-
phosphate backbone that is brought about by phosphodiester bond formation.
Without the phosphodiester bond, the nucleotides of DNA or RNA would not hold
together and the DNA would no longer be replicated to cause semi conservative
replication where after one round of replication, every new DNA double helix would
be a hybrid consisting of one strand of old DNA, bounded to a single strand of newly
synthesised DNA, if this process does not occur the cells cannot divide effectively
and cause mutations that lead to cancer cells. Furthermore, without the
phosphodiester bond there would be no nucleotides, no stability in DNA, which could
result in the protein being composed of many wrong amino acids. Ultimately, that
means that no nucleotides without phosphodiester bonds will be joined together, so
there will be no conservative replication resulting in mutations and this mutation is
transmitted somatically to daughter cells and via the germline to the next generation.
Other types of bonds include glycosidic bonds which are a new type of covalent
bond that binds monosaccharides together to form disaccharide or polysaccharide
bonds. Glycosidic bonds are types of linkages between sugar molecules. There are
two types of glycosidic bonds; 1-4 alpha and 1-6 beta, for example: amylopectin in
plants is highly branched consisting of a-glucose molecules joined by a1-4 glycosidic
bonds with some a1-6 branching. The structure of amylopectin is all based on