Nucleic acids, and DNA in particular, are key macromolecules for the continuity of This progression from DNA to RNA to protein is called the “central dogma” of. Nucleic acids are the biopolymers, or small biomolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. If the sugar is a compound ribose, the polymer is RNA (ribonucleic acid); if The term nucleic acid is the overall name for DNA and RNA, members  ‎Nucleic acid structure · ‎Nucleic acids · ‎Nucleic acid sequence · ‎Locked nucleic acid. Read this article to learn about Composition and Structure of the Nucleic Acids: DNA & RNA! There are two major classes of nucleic acids: DNA and RNA.


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The chemical methods also enable the generation of altered nucleic acids that are not found in nature, [15] for example peptide nucleic acids dna and rna acids. Molecular composition and size[ edit ] Nucleic acids are generally very large molecules. Indeed, DNA molecules are probably the largest individual molecules known.

Well-studied biological nucleic acid molecules range in size from 21 nucleotides small interfering RNA to large chromosomes human chromosome 1 is a single molecule that contains million base pairs [16]. Each nucleotide consists of three components: The Sanger method has now been automated using fluorescent dyes to label the DNA, and a single machine can produce tens of thousands of DNA base sequences in a single nucleic acids dna and rna.

It is the first intermediate in converting the information from DNA into proteins essential for the working of a cell.

Nucleic acid - Wikipedia

Some RNAs also serve direct roles in cellular metabolism. RNA is made by copying the base sequence of a section of double-stranded DNA, called a gene, into a piece of single-stranded nucleic acid.

Chemical structure Whereas DNA provides the genetic information for the cell and is inherently quite stable, RNA has many roles and is much more reactive chemically.

In general, this instability is not a significant problem for the cell, because RNA is nucleic acids dna and rna being synthesized and degraded.

Introduction to nucleic acid (DNA and RNA) structure - Chemistry LibreTexts

In DNA, which is usually double-stranded, the bases in one strand pair with complementary bases in a second DNA strand. In RNA, which is usually single-stranded, the bases pair with other bases within the same molecule, leading to complex three-dimensional structures.

Depending on the amount of salt present, either 11 or 12 base pairs are found nucleic acids dna and rna each turn of the helix.

Single-stranded RNAs are flexible molecules that form a variety of structures through internal base pairing and additional non-base pair interactions.

They can form hairpin loops such as those found in transfer RNA tRNAas well as longer-range interactions involving both the bases and the phosphate residues of two or more nucleotides.

This leads to compact three-dimensional structures. Most of these structures nucleic acids dna and rna been inferred from biochemical data, since few crystallographic images are available for RNA molecules.

More than 90 different modifications have been documented, including extensive methylations and a wide variety of substitutions around the ring.

Introduction to nucleic acid (DNA and RNA) structure

In some cases these modifications are known to affect structure and are essential for function. In eukaryotes the mRNA molecules are more elaborate. Eukaryotic mRNA molecules are usually composed of small segments of the original gene and are nucleic acids dna and rna by a process of cleavage and rejoining from an original precursor RNA pre-mRNA molecule, which is an exact copy of the gene as described in the section Splicing.


In general, prokaryotic mRNAs are degraded very rapidly, whereas nucleic acids dna and rna cap structure and the polyA tail of eukaryotic mRNAs greatly enhance their stability. They also assist with the catalysis of protein synthesis. In the prokaryote E. In eukaryotes the numbers are much larger.

Anywhere from 50 to 5, sets of rRNA genes and as many as 10 million ribosomes may be present in a single cell.

Nucleic acid

In eukaryotes these rRNA genes are looped out of the main chromosomal fibres and nucleic acids dna and rna in the presence of proteins to form an organelle called the nucleolus. The nucleolus is where the rRNA genes are transcribed and the early assembly of ribosomes takes place. The tRNA molecules contain 70 to 80 nucleotides and fold into a characteristic cloverleaf structure.


Specialized tRNAs exist for each of the 20 amino acids needed for protein synthesis, and in many cases more than one tRNA for each amino acid is present.

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