DNA stands for Deoxyribose Nucleic Acid while RNA stands for Ribose Nucleic Acid. Compounds of Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorus. Made up of Nucleotide Monomers (Polynucleotides). A nucleotide consists of a Nitrogenous base, a Pentose Sugar & Phosphate Group.
Nucleoside: Nitrogenous Base + Sugar.
5 Nitrogenous Bases are there :
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Cytosine, Uracil, and Thymine are the Pyrimidine Derivatives with a single ring structure.
Adenine and Guanine are the Purine Derivatives with a double ring structure.
The pentose sugars are of 2 types:
Thus, the Nitrogenous bases, combining with Pentose Sugars and a Phosphate Group, form 8 type of Nucleotide Molecules :
- Cytosine + Ribose Sugar + Phosphate
- Cytosine + Deoxyribose Sugar + Phosphate
- Uracil + Ribose Sugar + Phosphate
- Thymine + Deoxyribose Sugar + Phosphate
- Adenine + Ribose Sugar + Phosphate
- Adenine + Deoxyribose Sugar + Phosphate
- Guanine + Ribose Sugar + Phosphate
- Guanine + Deoxyribose Sugar + Phosphate
Deoxyribose Nucleic Acid Molecule
Long and highly complex, spirally twisted, right-handed double helix, Ladder like structure formed by 2 polynucleotides strands. Base thymine is present, but never uracil. Wilkins, Watson and Crick (1953) received Noble Prize for Deoxyribose Nucleic Acid Structure. Adenine links with Thymine by two hydrogen bonds. Guanine with cytosine by three hydrogen bonds. A single Deoxyribose Nucleic Acid molecule has millions of pairs of nucleotide monomers. Deoxyribose Nucleic Acid contains “Blue Print” of life. With RNA’s help, it directs the synthesis of all structural and functional proteins of Protoplasm.
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Difference Table of DNA and RNA
|It usually occurs inside nucleus and some cell organelles.||Very little RNA occurs inside nucleus. Most of it is found in the cytoplasm.|
|DNA is the genetic material.||RNA is not the genetic material except in certain viruses. e.g., TNIV, Reovirus.|
|It is double stranded with the exception of some viruses.||RNA is single stranded with the exception of some viruses (e.g., double stranded in Reovirus).|
|DNA shows regular helical coiling.||There is no regular coiling except in parts of RNA.|
|DNA forms chromosomes of similar structures.||rRNA forms ribosomes.|
|DNA contains several million nucleotides.||Depending upon the type, RNA contains 10-12000 nucleotides.|
|DNA is of only two types, nuclear and extra nuclear.||There are at least three types of RNA-rRNA, mRNA and tRNA|
|It contains deoxyribose sugar.||It contains ribose sugar.|
|Nitrogen base thymine occurs in DNA along with three other-adenine, cytosine and guanine.||Thymine is replaced by uracil in RNA. The other three are adenine, cytosine and guanine.|
|Renaturation after melting is slow.||It is quite fast.|
|Hydrogen bonds tire formed between complementary nitrogen bases of the opposite strands of DNA (A : T, C : G)||Base pairing through hydrogen bonds occurs only in the coiled parts.|
|It replicates to form new DNA molecules.||It cannot replicate itself except in RNA-RNA viruses.|
|DNA transcribes genetic information to RNA.||RNA translates the transcribed message for forming polypeptides.|
|DNA controls heredity, evolution, metabolism, structure and differentiation.||RNA controls only protein synthesis.|
|Its quantity is fixed for cell.||The quantity of RNA of a cell is variable.|
|DNA controls metabolism and genetics including variations.||It only controls metabolism under instructions from DNA.|
|Purine and pyrimidine bases are in equal number.||There is no proportionality between number of purine and pyrimidine bases.|
|It can be hydrolyzed by enzyme DNA-ase.||RNA is hydrolyzed by RNA-ase.|