Forms of DNA and RNA in Genetic Specifications

Mar 2, 2013

DNA ( Deoxyribonucleic acid ) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. 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 genetic information.

DNA consists of two long polymers simple units called nucleotides, with backbones made ​​of sugars and phosphate groups joined by ester bonds. These two strands run in opposite directions to each other and are therefore anti-parallel. Attached to each sugar is one of four types of molecules called bases. This is the sequence of the four bases along the backbone that encodes information. This information is read using the genetic code, which determines the order of amino acids in proteins. The code is read by copying stretches of DNA into RNA nucleic acid related, in a process called transcription.

RNA ( RiboNucleicAcid ) compound which is the genetic material, and plays a major role in genetic expression. In the dogma principal ( central dogma ) molecular genetics, RNA mediates between DNA and the information carried phenotypic expression embodied in the form of protein.

The basic structure of RNA is similar to DNA. RNA is a polymer composed of a number of nucleotides. Each nucleotide has a phosphate group, a pentose group, and a group of nitrogen bases ( base N ). Polymer composed of alternating bond between the phosphate group of one nucleotide pentose group of another nucleotide.

DNA does not usually exist as a single molecule, but instead as a tightly-associated pair of molecules. These two long strands entwine like vines, in the shape of a double helix. This arrangement of DNA strands is called antiparallel. The asymmetric ends of DNA strands are referred to as the 5′ ( five prime ) and 3′ ( three prime ) ends. One of the major differences between DNA and RNA is the sugar, with 2-deoxyribose being replaced by the alternative pentose sugar ribose in RNA. The four bases found in DNA are adenine ( abbreviated A ), cytosine ( C ), guanine ( G ) and thymine ( T ). A fifth pyrimidine base, called uracil ( U ), usually takes the place of thymine in RNA and differs from thymine by lacking a methyl group on its ring.

Comparison chart
DeoxyriboNucleicAcid RiboNucleicAcid
A nucleic acid that contains the genetic instructions used in the development and functioning of all modern living organisms(scientists believe that RNA may have been the main genetic material in primitive life forms). A single-stranded chain of alternating phosphate and ribose units with the bases Adenine, Guanine, Cytosine, and Uracil bonded to the ribose. RNA molecules are involved in protein synthesis and sometimes in the transmission of genetic information.
Medium of long-term storage and transmission of genetic information Transfer the genetic code needed for the creation of proteins from the nucleus to the ribosome.
The helix geometry of DNA is of B-Form. DNA is completely protected by the body, i.e., the body destroys enzymes that cleave DNA. DNA can be damaged by exposure to Ultra-violet rays The helix geometry of RNA is of A-Form. RNA strands are continually made, broken down and reused. RNA is more resistant to damage by Ultra-violet rays.
Double- stranded molecule with a long chain of nucleotides A single-stranded molecule in most of its biological roles and has a shorter chain of nucleotides
Deoxyribose sugar; phosphate backbone; Four bases: adenine, guanine, cytosine and thymine Ribose sugar; phosphate backbone. Four bases: adenine, guanine, cytosine, and uracil
A-T (Adenine-Thymine ), G-C( Guanine-Cytosine ) A-U ( Adenine-Uraci l), G-C ( Guanine-Cytosine )
Deoxyribose sugar in DNA is less reactive because of C-H bonds. Stable in alkaline conditions. DNA has smaller grooves, which makes it harder for enzymes to "attack" DNA. Ribose sugar is more reactive because of C-OH ( hydroxyl ) bonds. Not stable in alkaline conditions. RNA has larger grooves, which makes it easier to be attacked by enzymes.
DNA is self-replicating. RNA is synthesized from DNA when needed.

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