Everything about Biomolecule totally explained
A
biomolecule is a
molecule that naturally occurs in living organisms. Biomolecules consist primarily of
carbon and
hydrogen, along with
nitrogen,
oxygen,
phosphorus and
sulfur. Other elements sometimes are incorporated but are much less common.
Explanation
All known forms of
life are composed solely of biomolecules. For example,
humans possess
skin and
hair. The main component of hair is
keratin
, an agglomeration of
proteins which are themselves
polymers built from
amino acids. Amino acids are some of the most important building blocks used in nature to construct larger
molecules. Another type of building block are the
nucleotides, each of which consists of three components: either a
purine or
pyrimidine base, a
pentose sugar and a
phosphate group. These nucleotides mainly form the
nucleic acids.
Besides the polymeric biomolecules, numerous
organic molecules are absorbed by living systems.
Types of biomolecules
A diverse range of biomolecules exist, including:
Nucleosides and nucleotides
Nucleosides are molecules formed by attaching a
nucleobase to a
ribose ring. Examples of these include
cytidine,
uridine,
adenosine,
guanosine,
thymidine and
inosine.
Nucleosides can be
phosphorylated by specific
kinases in the cell, producing
nucleotides, which are the molecular building blocks of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Saccharides
Monosaccharides are the simplest form of carbohydrates. They essentially contain an
aldehyde or
ketone group in their structure. Examples of monosaccharides are the
hexoses
glucose,
fructose, and
galactose and
pentoses, ribose, and
deoxyribose
Disaccharides are formed when two monosaccharides form a bond with removal of water. Examples of disaccharides include
sucrose,
maltose, and
lactose
Monosaccharides and disaccharides are sweet, water soluble, and crystalline.
Polysaccharides are polymerized monosaccharides, complex, unsweet carbohydrates. Examples are
starch,
cellulose, and
glycogen. They are generally large and often have a complex, branched, connectivity. They are insoluble in water and don't form crystals. Shorter polysaccharides, with 11-40 monomers, are sometimes known as
oligosaccharides.
Lipids
Lipids are chiefly
fatty acid esters, and are the basic building blocks of
biological membranes. Another biological role is energy storage (for example,
triglycerides). Most lipids consist of a
polar or
hydrophilic head (typically glycerol) and one to three nonpolar or
hydrophobic fatty acid tails, and therefore they're
amphiphilic. Fatty acids consist of unbranched chains of carbon atoms that are connected by single bonds alone (
saturated fatty acids) or by both single and
double bonds (
unsaturated fatty acids). The chains are usually 14-24 carbon groups long, but it's always an even number.
For lipids present in biological membranes, the hydrophilic head is from one of three classes:
Glycolipids, whose heads contain an oligosaccharide with 1-15 saccharide residues.
Phospholipids, whose heads contain a positively charged group that's linked to the tail by a negatively charged phosphate group.
Sterols, whose heads contain a planar steroid ring, for example, cholesterol.
Other lipids include prostaglandins and leukotrienes which are both 20-carbon fatty acyl units synthesized from arachidonic acid.
They are also known as fatty acids
Amino acids
Amino acids are molecules that contain both amino and carboxylic acid functional groups. (In biochemistry, the term amino acid is used when referring to those amino acids in which the amino and carboxylate functionalities are attached to the same carbon, plus proline which isn't actually an amino acid).
Amino acids are the building blocks of long polymer chains. With 2-10 amino acids such chains are called peptides, with 10-100 they're often called polypeptides, and longer chains are known as proteins. These protein structures have many structural and functional roles in organisms.
There are twenty amino acids that are encoded by the standard genetic code, but there are more than 500 natural amino acids. When amino acids other than the set of twenty are observed in proteins, this is usually the result of modification after translation (protein synthesis). Only two amino acids other than the standard twenty are known to be incorporated into proteins during translation, in certain organisms:
Selenocysteine is incorporated into some proteins at a UGA codon, which is normally a stop codon.
Pyrrolysine is incorporated into some proteins at a UAG codon. For instance, in some methanogens in enzymes that are used to produce methane.
Besides those used in protein synthesis, other biologically important amino acids include carnitine (used in lipid transport within a cell), ornithine, GABA and taurine.
Protein structure
The particular series of amino acids that form a protein is known as that protein's primary structure. Proteins have several, well-classified, elements of local structure formed by action of various forces like Hydrogen Bond, Sulphur dibridges, Hydrophobic interactions, Van Der Walls forces, etc and the structure formed as the result of these forces is termed secondary structure. The overall 3D structure of a protein is termed its tertiary structure. When two or more different polypeptide chains cluster to form a protein, quaternary structure of protein is formed.
Metalloproteins
A metalloprotein is a molecule that contains a metal cofactor. The metal attached to the protein may be an isolated ion or may be a complex organometallic compound or organic compound, such as the porphyrin group found in hemoproteins. In some cases, the metal is coordinated with both a side chain of the protein and an inorganic nonmetallic ion. This type of protein-metal-nonmetal structure is found in iron-sulfur clusters.
Vitamins
A vitamin is a compound that's generally not synthesized by a given organism but is nonetheless vital to its survival or health (for example coenzymes). These compounds must be absorbed, or eaten, but typically only in trace quantities. When originally discovered by a Polish doctor, he believed them to all be basic. He therefore named them vital amines. The l was later dropped to form the word vitamines.
Further Information
Get more info on 'Biomolecule'.
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