Chemical Composition of Biomolecules
* All the carbon compounds derived from living tissues are called biomolecules.
* In biology, the functional groups of organic chemistry are present as amino acids, fatty acids and nucleotide bases.
* In alpha amino acids, the amino group and carboxylic group are present on the same αcarbon atom of the amino acid.
* A fatty acid has a carboxyl group attached to an R group.
* Lipids are a group of biomolecules that include fats, waxes, fat-soluble vitamins and glycerides.
* Lipids that contain phosphorous and a phosphorylated organic compound are known as phospholipids.
* When carbon compounds with heterocyclic rings are attached to a sugar, they are called nucleosides.
* If a phosphate group is also found esterified to a sugar, they are called nucleotides.
Polysaccharides and Nucleic Acids
* Biomolecules can be broadly divided into two typesbiomicromolecules and biomacromolecules.
* Biomicromolecules are chemical compounds found in the acid-soluble fraction with molecular weights ranging from 18 to 800 daltons.
* Biomacromolecules are compounds found in the acid-insoluble fraction with molecular weights in the range of 10,000 daltons and above.
* Biomacromolecules are of three types – polysaccharides, nucleic acids and proteins.
* Polysaccharides are thread-like structures consisting of different monosaccharides as building blocks.
* Lipids have molecular weight less than 800 daltons but they are found in the acid insoluble fraction.
* The nucleic acid containing deoxyribose is called deoxyribonucleic acid or DNA while the one with ribose is called ribonucleic acid or RNA.
Protein and its Structure
* Proteins are organic compounds made up of amino acids arranged in a linear chain and linked by peptide bonds.
* There are 20 types of amino acids that come together to form proteins. Therefore, proteins are also heteropolymers.
* Amino acids that go into the making of proteins can be essential or non-essential.
* Biochemists have described the protein structure as primary, secondary, tertiary and quaternary.
* Some examples of proteins are collagen, RUBISCO, trypsin, insulin, antibody and Glut-4.
Nature of Bond Linking Monomers in a Polymer
* A polymer is formed when many monomers come together and bond in long chains.
* Proteins are amino acids linked by peptide bonds.
* Polysaccharides are formed when several monosaccharides are linked together by a glycosidic bond.
* The phosphate and hydroxyl groups of sugar join to form an ester bond.
* The ester bonds formed by the phosphate group, between the third and fifth carbon atoms of adjacent pentose sugar rings, are called phosphodiester bonds.
* The Watson Crick Model defines the B- form of DNA as the native conformation of DNA in solution.
* DNA exists as a double helix with two strands of polynucleotide that run in opposite directions.
Concept of Metabolism
* All living organisms contain innumerable organic compounds or biomolecules in a certain concentration.
* Biomolecules constantly break up and are remade.
* The entire set of biochemical reactions that takes place in living organisms and helps them maintain life is known as metabolism.
* The series of linked chemical reactions that transforms biomolecules is called metabolic pathways.
* Metabolic pathways can be categorised as anabolic pathways and catabolic pathways.
* ATP or adenosine triphosphate is an important biomolecules that contains energy in its chemical bonds.
* The living state is a steady state or a non-equilibrium state, which is essential for living organisms to be able to work constantly.
Introduction to Enzymes
* Enzymes act as biological catalysts and change the rate of reactions without themselves getting altered.
* Just as with proteins, enzymes have a primary, secondary and tertiary structure.
* The tertiary structure of an enzyme folds and criss-crosses on itself, creating many crevices or pockets. One of these pockets is called the active site.
* A substrate fits into the active site of the enzyme and enables it to catalyse reactions at a high rate.
* The rate of a reaction is defined as the amount of a product formed per unit time.
* Metabolic pathways, catalysed by enzymes, yield different metabolic end products under different conditions.
Chemical Conversions
* Enzymes are three dimensional protein structures with an active site.
* Enzymes convert a chemical or a substrate denoted as ‘S’ into a product or ‘P’.
* At the end of any reaction, the enzyme remains unaltered and can be used by another molecule.
* The conversion of a substrate into a product takes place through a catalytic cycle of the enzyme.
* Activation energy is the minimum amount of energy required for the chemical reactionto take place.
* Enzymes lower the activation energy due to which the substrate transforms into a product at a faster rate.
Factors Affecting Enzyme Activity
* Enzymes have a primary, secondary and tertiary structure just like proteins.
* Factors that affect enzyme activity are temperature and Ph, a change in substrate concentration and the binding of specific chemicals.
* Every enzyme demonstrates its highest activity at a particular temperature and pH level which are called optimum temperature and optimum pH.
* The process y which a chemical shuts off enzyme activity is called inhibition and the chemical that causes it is called an inhibitor.
* Am inhibitor whose molecular structure closely resembles that of a substrate is known as a competitive inhibitor.
Classification of Enzymes
* Enzymes help the various processes in a biological cell to take place at a significant rate.
* Depending on the types of reactions they catalyse, enzymes have been divided into six classes.
* These classes are oxidoreductases or dehydrogenases, transferases, hydrolases, lyases, isomerases and ligases.
* When non-protein chemical compounds bind to the enzyme, they are called co-factors.
* The protein part of enzymes with co-factors is known as apoenzyme.
* Co-factors are of three types: prosthetic groups, co-enzymes and metal ions.