GENETIC MATERIAL
1. GENERAL INTRODUCTION
(i) Nucleic acid was first isolated from nucleus of the pus cells by a swiss physician Friedrich.
Meischer in 1868-69 Meise called it nucleain.
(ii) In 1884 Oskar, Hartwing described that nuclein is the substance responsible for transmission
of hereditary character.
(iii) Nuclein was named nucleic acid by Altman in 1889.
(iv) Behrens in 1938 showed that most of the DNA is found in nucleus and most of the RNA in
cytoplasm.
2.Location
Nucleic acid is mainly found in nucleus . It occurs in cytoplasm, mile chondria, plastids, as well
as in centrioles.
3.Composition
(i) Nucleic acid is composed of large number of nucleotides.
(ii) So the nucleic acid are polymer of nucleotides or polynucleotide
(iii) Nucleotide is composed of nitrogenous base + pentose sugar phosphate.
(iv) Nitrogenous bases are of two types double ringed punine and single ringed pyrimidine.
(v) Pentose sugar is of two types ribose and deoxyribose.
4.Types
There are two types of nucleic acids deoxyribonucleic acid or DNA ano, ribonucleic acid or
RNA.
(i) Deoxy Ribonucleic Acid (D.N.A.)
(a) Introduction
(i) Found in Nucleus
(ii) AveryMcleoid and Mccarty told that hereditary characters are stored in DNA
(iii) They performed their experiment on pneumococcus bacteria.
(iv) Double helical structure of DNA was given by Watson and Crick
(v) Synthesis of DNA was done by Rich.
(vi) Chargaff told that ratio of A or T and G or C = 1
(b) Location
(i) In prokaryotic cells DNA occurs in the cytoplasm.
(ii) In eukaryotic cells DNA is found in nucleus.
(iii) DNA also occurs in small quantity in some cytoplasmic organelles such as mitochondria and
plastids,
This is called extranuclear of organeller DNA.
, (c) Quantity
(i). In a particular species DNA content is constant in all the cells.
(ii) Just before the cell division DNA content get doubled.
(iii) In gametes number of DNA is just half.
(d) Chemical Composition
(i) Chemical structure of DNA was explained by P.A. Levene
(ii) DNA is the largest macromolecule is an organism.
(iii) It is a long double chain of deoxyribonucleotide.
(iv) Each deoxyribonucleotide composed of 3 molecules of PO4,5 carbon deoxyribose surgar
(C5H10O4) and a nitrogen base
(e) Nitrogenous base
(i) The nitrogenous base includes purine and pyrimidine.
(ii) Nitrogenous bases was discovered by Kossel.
(f)Purine
(i) Purine is 9 membered double ringed structure.
(ii) It includes adenine (A) and Guanine (G)
(g) Pyrimidine
(i) Pyrimidine is 6 membered, single ringed structure.
(ii) It includes thymine (T) or Cytosine (C)
(h) Nucleoside
(i) When nitrogen base combined with deoxyribose sugar it constitute a nucleoside.
(ii) Nucleosides are of 4 types which are as follows:
S.No. Deoxyribonucleoside
1 Adenine + Deoxyribose - Deoxyadenosine
2 Guanine + Deoxyribose - Deoxyguanosine
3 Gytosine + Deoxyribose - Deoxycytidine
4 Thymine + Deoxyribose - Deoxythymidine
(i) Nucleotide
(i) Nucleotide is combination of nitrogenous base, sugar and phos
(ii) Nucleotide are of 4 types which are as follows
S.No. Deoxyribonucleotide phosphate.
1. Deoxyadenosine mono, di, tri, phosphate dAMP, dADP, dATP
2 Deoxycytidine mono, di, tri, phosphate dGMP, dGDP, dGTP
3 Deoxycytidine mono, di, tri, phosphate dCMP, dCDP, dCTP
4. (i) Deoxy thymidine mono, di,phosphate dTMP, dTDP, dTTP
1. GENERAL INTRODUCTION
(i) Nucleic acid was first isolated from nucleus of the pus cells by a swiss physician Friedrich.
Meischer in 1868-69 Meise called it nucleain.
(ii) In 1884 Oskar, Hartwing described that nuclein is the substance responsible for transmission
of hereditary character.
(iii) Nuclein was named nucleic acid by Altman in 1889.
(iv) Behrens in 1938 showed that most of the DNA is found in nucleus and most of the RNA in
cytoplasm.
2.Location
Nucleic acid is mainly found in nucleus . It occurs in cytoplasm, mile chondria, plastids, as well
as in centrioles.
3.Composition
(i) Nucleic acid is composed of large number of nucleotides.
(ii) So the nucleic acid are polymer of nucleotides or polynucleotide
(iii) Nucleotide is composed of nitrogenous base + pentose sugar phosphate.
(iv) Nitrogenous bases are of two types double ringed punine and single ringed pyrimidine.
(v) Pentose sugar is of two types ribose and deoxyribose.
4.Types
There are two types of nucleic acids deoxyribonucleic acid or DNA ano, ribonucleic acid or
RNA.
(i) Deoxy Ribonucleic Acid (D.N.A.)
(a) Introduction
(i) Found in Nucleus
(ii) AveryMcleoid and Mccarty told that hereditary characters are stored in DNA
(iii) They performed their experiment on pneumococcus bacteria.
(iv) Double helical structure of DNA was given by Watson and Crick
(v) Synthesis of DNA was done by Rich.
(vi) Chargaff told that ratio of A or T and G or C = 1
(b) Location
(i) In prokaryotic cells DNA occurs in the cytoplasm.
(ii) In eukaryotic cells DNA is found in nucleus.
(iii) DNA also occurs in small quantity in some cytoplasmic organelles such as mitochondria and
plastids,
This is called extranuclear of organeller DNA.
, (c) Quantity
(i). In a particular species DNA content is constant in all the cells.
(ii) Just before the cell division DNA content get doubled.
(iii) In gametes number of DNA is just half.
(d) Chemical Composition
(i) Chemical structure of DNA was explained by P.A. Levene
(ii) DNA is the largest macromolecule is an organism.
(iii) It is a long double chain of deoxyribonucleotide.
(iv) Each deoxyribonucleotide composed of 3 molecules of PO4,5 carbon deoxyribose surgar
(C5H10O4) and a nitrogen base
(e) Nitrogenous base
(i) The nitrogenous base includes purine and pyrimidine.
(ii) Nitrogenous bases was discovered by Kossel.
(f)Purine
(i) Purine is 9 membered double ringed structure.
(ii) It includes adenine (A) and Guanine (G)
(g) Pyrimidine
(i) Pyrimidine is 6 membered, single ringed structure.
(ii) It includes thymine (T) or Cytosine (C)
(h) Nucleoside
(i) When nitrogen base combined with deoxyribose sugar it constitute a nucleoside.
(ii) Nucleosides are of 4 types which are as follows:
S.No. Deoxyribonucleoside
1 Adenine + Deoxyribose - Deoxyadenosine
2 Guanine + Deoxyribose - Deoxyguanosine
3 Gytosine + Deoxyribose - Deoxycytidine
4 Thymine + Deoxyribose - Deoxythymidine
(i) Nucleotide
(i) Nucleotide is combination of nitrogenous base, sugar and phos
(ii) Nucleotide are of 4 types which are as follows
S.No. Deoxyribonucleotide phosphate.
1. Deoxyadenosine mono, di, tri, phosphate dAMP, dADP, dATP
2 Deoxycytidine mono, di, tri, phosphate dGMP, dGDP, dGTP
3 Deoxycytidine mono, di, tri, phosphate dCMP, dCDP, dCTP
4. (i) Deoxy thymidine mono, di,phosphate dTMP, dTDP, dTTP
