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Peptides

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 PEPTIDES FUNCTIONS  Peptides from the Greek word means digested are short polymers of amino acid monomers linked by peptide bonds, the covalent chemical bonds formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule.  Peptides are distinguished from proteins on the basis of size, typically containing fewer than 50 monomer units. The shortest peptides are dipeptides consisting of two amino acids joined by a single peptide bond. There are also tripeptides, tetrapeptides etc. Amino acids which have been incorporated into a peptide are termed "residues"; every peptide has a N-terminus and C-terminus residues on the ends of the peptide. A polypeptide is a long, continuous, and unbranched peptide.   Proteins consist of one or more polypeptides arranged in a biologically functional way and are often bound to cofactors, or other proteins.  Long peptides such as amyloid beta can be considered proteins, wherea...

PHYSICAL AND CHEMICALS PROPERTIES OF AMINO ACIDS

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 PHYSICAL PROPERTIES  Solubility  Most of the amino acids are usually soluble in water and insoluble in organic solvents. Melting point Amino acids generally melt at higher temperatures, often above 200 Celsius. Taste  Amino acids may be sweet (Gly,Ala,Val), tasteless (Leu) or bitter (Arg, Ile), Monosodium glutamate (MSG; ajinomotto) is used as flavouring agent in food industry. Optical properties  All amino acids except glycine possess optical isomers due to the presence of asymmetric carbon atom. Some amino acids have a second asymmetric carbon e.g. isoleucine, threonine.  On heating to high temperatures, they decompose. Amino acids are colourless, crystalline solid. Peptide bond formation  Amino acids can connect with a peptide bond involving their amino and carboxylate groups. Covalent bond formed between the alpha-amino group of one amino acid and an alpha-carboxyl group of other forming -CO-NH- linkage.  Peptide bonds are planar and partiall...

What is nitrogen oxides?

  Oxides of nitrogen are a mixture of gases that are composed of nitrogen and oxygen. At high-temperature oxygen and nitrogen undergo an   endothermic   reaction producing various oxides of nitrogen but oxygen and nitrogen cannot react at low temperature. The general term for nitrogen oxide is denoted NOx. The term NOx is common means that molecule containing one nitrogen and one or more oxygen atoms, but actually, it is a mixture of NO (nitric oxide) and NO 2 . Different types of oxides of nitrogen are present in this environment they have a valence state from 1 to 5 for example : Nitrous oxide (N 2 O) Nitric oxide (NO) Dinitrogen dioxide(N 2 O 2 ) Dinitrogen trioxide (N 2 O 3 ) Nitrogen dioxide (NO 2 ) Dinitrogen tetroxide(N 2 O 4 ) Dinitrogen pentoxide(N 2 O 5 ) All NOx gases are harmful to human health and the environment. The environmental pollutants under the oxides of nitrogen include nitrous oxide(N 2 O), nitric oxide (NO) and nitrogen dioxide(NO 2 ).nitric o...

What are Group-15 elements?

  These elements are called the   nitrogen family .  It consists of   nitrogen , phosphorus, arsenic, antimony,  bismuth, and meconium. They are present on the right side of the periodic table.  All the elements are arranged based on their atomic weight. The elements with similar properties reside in a column called the group. Trends in Group 15 Elements 1) Electronic configuration  These group elements have a general electronic configuration which is ns 2 np 3 . As all have the same  valence electronic configuration , they belong to the same family. Their s-orbital always remains occupied by electrons, but the p-orbital is half-filled. That is why they are very stable elements. 2) Atomic radii and ionic radii Atomic radii, as well as ionic radii, increase if we go from the upper elements to the lower elements. It is because of adding an extra electronic orbital. But in the case of arsenic and bismuth, this increment is not that much because ...

CLASSIFICATION OF HALOALKANES & HALOARENES

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  Haloalkanes   Haloalkanes These have hydrocarbons made up with  aliphatic  alkanes and one or more hydrogen atoms replaced by  halogens  (elements such as Chlorine, Bromine, Fluorine, Iodine etc.). Here, the halogen atom is attached to the sp 3  hybridized carbon atom of the alkyl group. Example:  CH 3 Cl (Methyl Chloride)                           CH 3 CH 2 Br (Ethyl Bromide) These are saturated organic compounds where all the chemical bonds are attached to the carbon atom with single bonds and a single carbon atom is attached to the Halogen atom. Haloalkanes are made by aliphatic alkanes by the process of free radical halogenation. They are odourless compounds. These precipitate in SN 2  substitution reactions. Haloarenes Haloarenes are hydrocarbons consisting of  aromatic  ring/rings and one or more  hydrogen  atoms replaced by halogens. The halogen atom...

IDEAL & NON-IDEAL SOLUTION

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  Ideal and Non-Ideal Solution  A homogeneous mixture composed of two or more components is called a Solution. The component which has the highest quantity in a solution is the solvent. The solvent helps determine the physical state of the solution. A solute is a substance, in a solution, found in a smaller amount. The solution that has two components is called a  Binary Solution . The properties of a solution are further defined on basis of the Vapour Pressure, Boiling Point, Freezing Point and other Colligative Properties. The binary liquid in liquid solutions can be further divided into two terms: Ideal Solution Non-ideal Solution Ideal Solution The solutions which follow Raoult's law at all temperatures and concentrations are called  Ideal Solution . During its formation no change in enthalpy or volume takes place. In ideal solutions, the interaction between solute-solute and solvent-solvent molecules same as the interaction between solute and sol...