Biomolecules – structure and functions of proteins

Biomolecules – structure and functions of proteins

All living organisms are made up of the same elements and compounds. If we perform an analysis on animal tissue, plant tissue or on microbes the basic components are carbon, hydrogen, oxygen and several other components. The components do not vary even in non-living things. All the carbon compounds that we get through living tissue can be called biomolecules. First important molecules is 

Carbohydrates –

It is the main source of energy in living beings. Simple carbohydrates which are soluble in water and sweet in taste are called sugar. Carbohydrates are the body’s primary source of energy.. In a normal man 55 – 65 % of energy available to him is in the form of carbohydrates present in his diet. 

Classification of carbohydrates-

• Monosaccharides- 

These are the simplest sugars that can not be further hydrolysed. Saccharides have either a ring or a straight chain structure.. Classification of monosaccharides on the basis of no of carbons. 

Trioses number of carbon 3 simplest monosaccharides example – DHAP , PGAL 

Tetroses number of carbon 4 

Example – erythrose,  erythrulose 

Pentose number of carbon 5 

Example – xylose,  xylulose, deoxyribose, arabinose, ribose, ribulose. 

Hexoses- number of carbon 6 

Glucose – it is abundantly found in grapes so known as grape sugar. It is also abundantly found in blood, so also known as blood sugar. Glucose is the main respiratory substance. 

Fructose – sweetest carbohydrates, it is mostly found in honey and fruits, so also known as fruit sugar. 

Galactose- most abundantly in brain and nervous tissue, so called brain sugar. It never occurs in free form. Example – lactose 

Heptoses- number of carbon 7 ( largest monosaccharides) 

Example – sedoheptulose

• Oligo-saccharides – 

 oligo-saccharides are those carbon on which 10 to 12 monosaccharides are formed during the breakdown of these types of carbohydrates. These are linked by glycosidic bonds. 

Disaccharides – these are composed of two monosaccharides, example – maltose , sucrose, lactose. 

Maltose – commonly known as malt sugar. It is a compound that is found in the middle of the food digestion. 

Lactose- it is the milk sugar. Glucose and galactose are the two sugars that make it up.. It is the least sweet sugar. Maximum lactose is found in human milk. 

Sucrose- sucrose is known as table sugar, cane sugar, invert sugar and helps in transportation in plants so also known as, plant sugar. Made up of glucose and fructose. 

Trehalose- it is present in a haemolymph of an insect. 

• Polysaccharides- 

These are made up of a large number of monosaccharides. 

According to function they are classified as nutritive and structural. They are insoluble in water and they are not sweet in taste. 

• Homopolysaccharides–  they are composed of the same monomer. 

Cellulose- it is a linear polymer. It is also used to form artificial silk. Paper is made of plant pulp that is made up of cellulose. 

Starch – it is mainly stored in plants. Starch present in potatoes contains 20% amylose and 80% amylopectin. Starch forms a helical structure so it holds an iodine molecule in it. 

Glycogen is also referred to as animal starch. It is a highly branched polymer. Glycogen is the stored food of fungi. 

Chitin – second most abundant organic molecule on earth. It is also called fungal cellulose 

It is the important component of the exoskeleton of arthropods and cell walls of fungi. 

Inulin – it is the smallest storage of Polysaccharides. It is water Soluble Polysaccharide and it is used to know the glomerular filtration rate. 

Dextrin – by hydrolysis of dextrin glucose and maltose are formed. 

• Heteropolysaccaharides- 

Composed of different monosaccharides units. 

Hyaluronic acid – found in vitreous humour, umbilical cord joints and connective tissue, as in the form of a lubricating agent. 

Chondroitin- it is present in connective tissue. 

Heparin – it is an anticoagulant of blood. 

Pectins – it is found in cell walls. Plant cement is another name for it. 

Hemicellulose- it is obtained from plants and used to form billiard and artificial ivory. 

Mucopolysaccharides 

• Peptidoglycan – 

Present in the cell wall of the bacteria. 

• Agar – Agar –

It is a Mucopolysaccharides which are obtained from red algae. It is used for preparing culture media. 

• Difference between gums and fevicol- 

Gums are naturally occurring mucopolysaccharides, whereas fevicol is a rubber-based synthetic adhesive. 

Lipids 

Fat and its derivative are combinaly known as lipids. Lipids are insoluble in water and soluble in organic solvents like acetones, chloroform, benzene, hot alcohol. Lipids contain more than twice the amount of energy as carbs. Animals store their food in the form of lipids to the greatest extent possible. 

• Simple lipids or neutral fats 
• Conjugated and compound lipids-

Phospholipids- example – lecithin, cephalin, sphingolipids. 

Glycolipids – cerebrosides , gangliosides, 

Derived lipids – steroid , sterols, sterones, chromolipid. 

Proteins 

Essential elements in protein are carbon, hydrogen, oxygen, nitrogen. Most of the proteins containing sulphur, Iodine, iron, and phosphorus are all found in some proteins.Proteins are the heteropolymers of Amino acid. Classification of proteins is based on amino acids. 

• Acidic Amino acid 

They have one amino acid and two carboxylic groups attached in their structure. Example – glutamic acid, aspartic acid. 

• Alkaline amino acid 

They have two amino and one carboxylic group example – histidine,  arginine, lysine. 

• Neutral amino acid 

They have one amino and one carboxyl group present in their structures. 

Special points on amino acids

Tryptophan – most complex amino acid, it is helpful in the synthesis of the plant hormone. 

Tyrosine – helps in synthesis of melanin pigment, thyroxine, adrenaline not adrenaline hormone. 

Cysteine and methionine are sulphur containing amino acids. 

Tyrosine, tryptophan, phenylalanine are aromatic amino acids, because they have a benzene ring in their structures. 

Except glycine all amino acids are laevorotatory. 

Conclusion

Nanomechanical sensors have been used to detect a wide range of biomolecules and microbes. In biosensing applications, molecular recognition techniques are crucial. Antigen–antibody interaction is one of the most potent strategies for detecting biomolecules, allowing for excellent sensitivity and selectivity in target detection. Antigen–antibody binding can detect not just peptides such as antigens and antibodies, but also microbes such as viruses and fungi. Enzyme reactions are another promising method for detecting biomolecules. Smaller biomolecules like hydrogen peroxide and glucose can be detected using enzyme reactions.