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(ii)Frenkel defect  : Frenkel defect is shown be ionic solids. The smaller ion (usually cation) is dislocated from its normal site to an interstitial site as shown in the figure . It creates a vacancy defect at its original site and an interstitial defect at its new site. Frenkel defect is also called a dislocation defect. Frenkel defect does not affect the density of the solid. Frenkel defect...
(i) Schottky defect The Schottky defect is basically a vacancy defect in ionic solids. To maintain electrical neutrality, the number of missing cations and anions are equal as shown in the figure. Schottky defect decreases the density of the substance. The number of such defects in ionic solids is quite significant. For example, in NaCl, there are approximately 106 Schottky pairs per cm3 at...
Conductor: A conductor may conduct electricity through the movement of electrons or ions. The conductivity of metals depends upon the number of valence electrons available per atom. The atomic orbitals of metal atoms form molecular orbitals which are so close in energy to each other as to form a band. If this band is partially filled or it overlaps with a higher energy unoccupied conduction...
Conductor: A conductor may conduct electricity through the movement of electrons or ions. The conductivity of metals depends upon the number of valence electrons available per atom. The atomic orbitals of metal atoms form molecular orbitals which are so close in energy to each other as to form a band. If this band is partially filled or it overlaps with a higher energy unoccupied conduction...
Atomic radius = 0.144 nm  for  a face-centred unit cell the length of a side of the cell is 0.407.
Orthoboric acid on heating gives metaboric acid with the removal of 4 molecules of water and on further heating, metaboric acid converts to tetraboric acid and later on Boron trioxide (boric anhydride)
The three types of RNA found in the cell are:-  (i) messenger RNA    (m - RNA) (ii) ribosomal RNA     (r - RNA) (iii) transfer RNA       (t - RNA)
Structural differences between DNA and RNA:-  (i) The sugar moiety in DNA is D-2-deoxyribose whereas sugar moiety in RNA is D-ribose. (ii) DNA contains thymine but it is absent in RNA. (iii) The helical structure of DNA is double-stranded whereas it is single-stranded in case of RNA. Functional differences between DNA and RNA:-  The main function of DNA is to provide heredity but the main...
The two strands in DNA are not identical but they held together because they form hydrogen bonds with each other. So they are not identical but complementary to each other. Cytosine forms a hydrogen bond with guanine and adenine forms a hydrogen bond with thymine. SO, that's why the two strands act as a complementary for each other.
Nucleoside                            Nucleotide 1.  It has base and sugar. 1. It has base, sugar and phosphoric acid. 2. The base is attached to 1' position of sugar. 2. In this, the base is attached to 1' positon and phosphoric acid to 5' position of sugar moiety.
Nucleic acids are biomolecules found in nuclei of a cell. They are of two types (i)  DNA - Deoxyribonucleic acid    (ii)  RNA -  Ribonucleic acid. The two important functions of nucleic acid are:-  (i) DNA present in chromosomes is responsible for heredity by transferring genes. (ii) Both the nucleic acids are responsible for the protein synthesis in a cell.
Vitamin A:-   Sources of this vitamin are carrots, butter and milk. Its deficiency causes Xerophthalmia (hardening of the cornea of the eye). Vitamin C:-   Sources of this vitamin are citrus fruits, amla and green vegetables. Its deficiency causes Scurvy (bleeding gums).
On the basis of their solubility in water vitamins are classified as:-  Water-soluble vitamins:-   Water soluble vitamins such as Vitamin C need to taken through diet regularly as they are excreted in the form of urine. water-insoluble and fat-soluble vitamin:-  Since these vitamins are not soluble in water so we don't need to take them regularly through diet. They are stored in liver and...
In denaturation of protein, globules get unfolded and helix gets uncoiled and also globular protein converts into fibrous protein. The primary structure remains the same but secondary and tertiary structure of the protein are destroyed so its biological activity changes.
Enzymes are the biocatalysts i.e., they catalyse biological reactions. Enzymes are very specific in nature and a particular enzyme can be used for a particular substrate. They are generally named after the name of a compound on which they act. For e.g conversion of maltose to glucose requires enzyme maltase.
Amino acid has both acidic group    and basic group . Thus in aqueous solution, the carboxyl group can lose a proton and the basic group (amine group) can accept a proton. In this way, it forms zwitter ion which can act in both ways i.e., acidic as well as basic. Hence amino acids are amphoteric in nature.
The difference between fibrous protein and globular protein is given below :-                 Fibrous Protein                            Globular Protein When the polypeptide chains run parallel and are held together with the help of hydrogen and disulphide bonds. In case of a globular protein, the chains of polypeptides coil around and give a spherical shape These proteins are...
Hydrogen bonding is the intermolecular bonding which helps in stabilising the -helix structure of proteins. Hydrogen bonds are formed between -NH- of amino acid and  of the adjacent turn of helix.
Secondary structures of proteins are found to exist in two types of structure:- (i)   Helix structure:-  α-Helix is a way in which a polypeptide chain forms all possible hydrogen bonds by twisting into a right-handed screw or helix with the –NH group of each amino acid and residue hydrogen bonded to the of an adjacent turn of the helix. (ii)  pleated sheet:-  In this structure, all peptide...
When a protein in its raw form, is subjected to change like change in temperature e.g boiling in hot water or chemical change like a variation in pH, the hydrogen bonds are disturbed. This results in unfolding of globules and uncoiling of the helix and thus protein loses its biological activity. This is called denaturation of the protein.
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