Nucleic Acid
A nucleic acid is a macromolecule composed of polynucleotide chains. These polynucleotide chains are made up of several monomers which are called nucleotides. These nucleotides carry genetic information or form structures within cells. Ncleic acids are found in every living organism including viruses as well. Nucleic acids were first discovered in 1871 by Friedrich Miescher.
Composition of Nucleic Acid
Each nucleotide comprises three components; Pentose Sugar, Phosphase Group and nitrogenous bases. Nitrogenous bases are of two types; purine and pyrimidine. Purines are based on Adenine (A) and Guanine (G) while Pyrimidine are based on Cytosine (C), Thymine (T) and Uracil (U). Nitrogenous bases found in the two nucleic acid types are different: adenini, cytosine and guanine found in both RNA and DNA, while thymine only occurs in DNA and uracil only occurs in RNA. Some other types of nucleic acid also occur, for example inosine found in strands of mature tRNA.
Pentose Sugar in ribonucleotide is ribose and in deoxyribonucloetides is deoxyribose. Phosphate linkage with pentose sugar is called Phosphodiester Linkage. Phosphoric acid has ability to develop ester linkage with hydro oxyle(OH) groups of pentose sugar.
Types of Nucleic Acid
There are two types of nucleic acids.
1- RNA
2- DNA
1- RNA
RNA stands for Ribonucleic acid, is a single polynucleotide chain comprising nucleotide monomers. These monomers plays significant role during transcription. It transcribed genetic information from deoxyribonucleic acid (DNA) into proteins during protein synthesis. In this way RNA acts as a messenger between DNA and ribosomes which are protein synthesis complexes present in cell. RNA forms vital portions of ribosomes and serves as an essential carrier of amino acids during protein synthesis. RNA exists in three types which include:
1- tRNA (transfer RNA)
2- mRNA (messenger RNA)
3- rRNA (ribosomal RNA)
2- DNA
DNA stands for Deoxyribonucleic acid, comprises two polynucleotide chains linked together by weak hydrogen bonds. There are two hydrogen bonds between A and T and three hydrogen bonds between C and G. DNA is heredity material contain genetic information passed from generation to generation. Evidence from the study of bacterium (Pneumococcus) that DNA is heredity material. This genetic information plays essential role in the development and functioning of all known living organisms.
The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes or are involved in regulating the use of this genetic information. The amount of DNA depends upon the number of chromosomes present.
DNA comprises four types of nitrogenous bases i-e cytosine, thymine, guanine and adenine. These bases are linked together to form a polynucleotide chain. Two polynucleotide chains coil around each other to form the double helical sucture of DNA molecule.
A nucleic acid is a macromolecule composed of polynucleotide chains. These polynucleotide chains are made up of several monomers which are called nucleotides. These nucleotides carry genetic information or form structures within cells. Ncleic acids are found in every living organism including viruses as well. Nucleic acids were first discovered in 1871 by Friedrich Miescher.
Composition of Nucleic Acid
Each nucleotide comprises three components; Pentose Sugar, Phosphase Group and nitrogenous bases. Nitrogenous bases are of two types; purine and pyrimidine. Purines are based on Adenine (A) and Guanine (G) while Pyrimidine are based on Cytosine (C), Thymine (T) and Uracil (U). Nitrogenous bases found in the two nucleic acid types are different: adenini, cytosine and guanine found in both RNA and DNA, while thymine only occurs in DNA and uracil only occurs in RNA. Some other types of nucleic acid also occur, for example inosine found in strands of mature tRNA.
Pentose Sugar in ribonucleotide is ribose and in deoxyribonucloetides is deoxyribose. Phosphate linkage with pentose sugar is called Phosphodiester Linkage. Phosphoric acid has ability to develop ester linkage with hydro oxyle(OH) groups of pentose sugar.
Types of Nucleic Acid
There are two types of nucleic acids.
1- RNA
2- DNA
1- RNA
RNA stands for Ribonucleic acid, is a single polynucleotide chain comprising nucleotide monomers. These monomers plays significant role during transcription. It transcribed genetic information from deoxyribonucleic acid (DNA) into proteins during protein synthesis. In this way RNA acts as a messenger between DNA and ribosomes which are protein synthesis complexes present in cell. RNA forms vital portions of ribosomes and serves as an essential carrier of amino acids during protein synthesis. RNA exists in three types which include:
1- tRNA (transfer RNA)
2- mRNA (messenger RNA)
3- rRNA (ribosomal RNA)
2- DNA
DNA stands for Deoxyribonucleic acid, comprises two polynucleotide chains linked together by weak hydrogen bonds. There are two hydrogen bonds between A and T and three hydrogen bonds between C and G. DNA is heredity material contain genetic information passed from generation to generation. Evidence from the study of bacterium (Pneumococcus) that DNA is heredity material. This genetic information plays essential role in the development and functioning of all known living organisms.
The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes or are involved in regulating the use of this genetic information. The amount of DNA depends upon the number of chromosomes present.
DNA comprises four types of nitrogenous bases i-e cytosine, thymine, guanine and adenine. These bases are linked together to form a polynucleotide chain. Two polynucleotide chains coil around each other to form the double helical sucture of DNA molecule.
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