Hydrogen bonds are bonds between two molecules caused by an electrostatic attraction between a proton and a negatively charged atom e.g. Nitrogen, Oxygen or Fluorine. These tend to be weak bonds compared to ionic or covalent bonds (but stronger than intermolecular bonds), however if there are a series of Hydrogen bonds, they can form a ring structure known as a chelate which is very strong and known for moving metal atoms. Greater viscosity and boiling points occur in substances that can form hydrogen bonds.
Hydrogen Bonds form between DNA Bases, Adenine-Thymine Cytosine-Guanine linking the DNA strands together and causing the DNA to coil in order to create its 3D structure (DNA Double Helix). They are important as they allow semi-conservative DNA replication to occur. This is where two identical copies of DNA are produced from an original DNA double Helix. Firstly The enzyme DNA helicase will break the hydrogen bonds formed between the bases to separate the DNA strands, free nucleotides will then bind with the complementary bases on the Strands and finally hydrogen bonds will reform between the bases (with the help of DNA polymerase) to create two new identical DNA molecules; without these hydrogen bonds we would not be able to produce new DNA, It is useful that hydrogen bonds are weak as they allow the breaking down of DNA to form new DNA.
Another use for Hydrogen bonds is that they cause proteins to form different shapes. Proteins have different structures known as the primary structure, secondary structure, tertiary structure and quaternary structure. In the primary structure it is simply a long chain of amino acids. However, the secondary structure does not remain flat and straight but instead hydrogen bonds form between the amino acid chains to form either a coiled structure (known as an Alpha helix) or a Beta pleated sheet structure. This secondary structure is then coiled/folded further to form a tertiary structure which is the final structure if there is only one polypeptide chain. However, if there is multiple polypeptide chains they can join together using bonds to form a quaternary structure e.g. Haemoglobin.
These different structures are important in determining the roles that these proteins play in their environment. For example Haemoglobin is very compact due to its structure (partially caused by hydrogen bonds) making it good for oxygen transport around the body.
Cellulose is a polysaccharide made from long chains of Beta glucose and it is primarily used to form the Cell Wall in plant cells. Hydrogen bonds are important in the structure as they form between cellulose molecules to create strong fibres known as microfibrils which are essential in cellulose in order to give the plant structural support, without these hydrogen bonds, the cell wall in plant cells would be weak and give no structural support.
Antibodies are folded proteins with a 3D structure caused by hydrogen bonding. They are used during an immune response and they are made up of two Light (short) polypeptide chains and two heavy (long) polypeptide chains which are bonded together to form a “Y” shape. The binding sites on the antibody bind with the complementary antigen to form an antibody-antigen complex, Hydrogen bonds (as well as van der…