- Biomolecules: All the carbon compounds that we get from living tissues.
- Macromolecules: Molecules which have molecular weights less than one thousand dalton.
- Amino acids: Organic compounds containing an amino group and one carboxyl group (acid group) and both these groups are attached to the same carbon atom called α carbon.
- Twenty types of amino acids occur in proteins.
- Based on number of amino and carboxyl groups, amino acids can be:
- Acidic: e.g. Glutamic acid
- Basic: e.g. Arginine and lysine
- Neutral: e.g. valine, alanine.
- Aromatic amino acids are tyrosine, phenylalanine, and tryptophan.
- Amino acids are ionizable into zwitterionic form.
Lipids :
- Water insoluble, containing C, H, O.
- They could be simple fatty acids.
- A fatty acid has a carboxyl group attached to an R group.
- The R group may be a methyl group (-CH3) or ethyl (-C2H5) or higher number of-CH2 group (1 carbon to 19 carbon). E.g. palmitic acid with 19 carbons, arachidonic acid has 20 carbons.
- Fatty acids could be saturated (without double bond) or unsaturated (with one more (c=c) double bond.
- Another example of lipid is glycerol which is trihydroxy propane.
- Many lipids may have both glycerol and fatty acids.
- Fatty acids esterified with glycerol to form mono, di or triglycerides.
- These are also called fats and oils based on the melting points.
- Oils have low melting points (e.g. gingely oil).
- Phospholipids are compound lipids with phosphorus and a phosphorylated organic compound. They are found in the cell membrane. e.g., Lecithin.
Nitrogen bases :
- Carbon compounds with heterocyclic rings.
- Purine: Adenine, Guanine.
- Pyrimidine: Cytosine, Uracil, Thymine.
- Nucleoside: Nitrogenous base + Sugar e.g., Adenosine, guanosine, thymidine Uridine and cytidine
- Nucleotide: Nitrogenous base + Sugar + Phosphate group. e.g., Adenylic acid, thymidylic acid, guanylic acid, uridylic acid and cytidylic acid.
- Nucleic acid: Polymer of nucleotides - DNA and RNA.
PRIMARY AND SECONDARY METABOLITES :
- Primary metabolites :
- Have identified function.
- Play known roles in physiological function.
- Carbohydrates, amino acids, fats and oils, nitrogen bases are the example of primary metabolites.
- Secondary metabolites :
- Have no definite function.
- Have no direct role in normal physiology.
- Alkaloid, favonoides, rubber, essential oils, antibiotics, coloured pigments. Scents, gums, spices are some example.
- Biomacromolecules : Biomolecules with molecular weights in the range of ten thousand daltons and above; found in acid insoluble fraction.
- Lipids are not strictly macromolecules as their molecular weights do not exceed 800 Da but form a part of the acid insoluble pool.
Proteins :
- Are polymers of amino acids linked by peptide bond.
- Is a heteropolymer not homopolymer.
- Essential amino acids: those can’t be synthesized in our body, have to be supplied through our diet.
- Non-essential amino acids: our body can synthesize it from other sources.
- Collagen is the most abundant protein in animal.
- Ribulose bisphosphate Carboxylase-Oxygenase (RUBISCO) is most abundant protein in the whole biosphere.
