All living tissues are made up of almost same types of element and compounds. All compounds or molecules present in living cells are said to be biomolecules.It consists of large macromolecules like proteins, polysaccharides, lipids, nucleic acid etc.
Metabolites are those biomolecules which are either utilised or synthesisedby the cellular machinery. These are of two types, namely; primary metabolites and secondary metabolites.
Primary metabolites have known functions and are involved in physiological processes, such as amino acids, carbohydrates, fats etc.
Secondary metabolites are the organic compounds which are not directly involved in the normal growth, development or reproduction in organisms. They arefound in only in plants, fungal and microbial cells.
Proteins are polypeptides. They are linear chains of amino acids linked by peptide bonds.
Amino acids are the organic compounds containing an amino group and an acidic group as substituent on the same carbon, i.e., the α-carbon. Hence, they are called α-amino acids.
The structure of protein iscategorised into four parts: primary structure, secondary structure, tertiary structure and quaternary structure.
The linear chain of amino acids are joined together by peptide bonds is called the primary structure of a protein. The first amino acid is also called as N-terminal amino acid. The last amino acid is called the C-terminal amino acid.
Within the long protein chains there are regions in which the chains are organised into regular structures known as alpha-helices (alpha-helixes) and beta-pleated sheets. These are the secondary structures in proteins. These secondary structures are held together by hydrogen bonds.
The formation of tertiary structure is usually formed by the burial of hydrophobic residues. Other interactions such as hydrogen bonding, ionic interactions, and disulfide bonds can also stabilise the tertiary structure.
The quaternary structure is the interaction between several chains of peptide bonds. The individual chains are called subunits. The individual subunits are not necessarily to be connected covalently, but might be connected by a disulfide bond.
Polysaccharides are long chains of sugars. They are long chains containing different monosaccharides as building blocks.In a polysaccharide chain, the right end is called the reducing end and the left end is called the non-reducing end.
The nucleic acids are polynucleotides. There are two types of nucleic acids found in living organisms,namely; DNA and RNA.
Metabolism is the set of chemical reactions that occur in living organisms in order to maintain a healthy life. The metabolism can be of two types, namely; catabolism and anabolism.
Enzyme is a protein (or protein-based molecule) that speeds up a chemical reaction in living organisms. An enzyme acts as catalyst for specific chemical reactions, converting a specific set of reactants (called substrates) into specific products. An active site is the main part of the enzyme where substrate fits and gets converted into product.The enzymes lower the activation energy of reactions and enhance the rate of reaction.