Each nucleotide in RNA contains a ribose sugar with carbons numbered 1′ through 5′. A base is attached to the First position generally adenine (A), cytosine (C), guanine (G) or uracil (U).
Adenine and guanine are purines, cytosine and uracil are pyrimidines. A phosphate group is attached to the 3rd position of one ribose and the 5th position of the next.
The phosphate groups have a negative charge each at physiological pH, making RNA a charged molecule (polyanion).
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The bases may form hydrogen bonds between cytosine and guanine, between adenine and uracil and between guanine and uracil.
However other interactions are possible, such as a group of adenine bases binding to each other in a bulge, or the GNRA tetra-loop that has a guanine-adenine base-pair.
An important structural feature of RNA that distinguishes it from DNA is the presence of a hydroxyl group at the 2′ position of the ribose sugar.
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The presence of this functional group causes the helix to adopt the A-form geometry rather than the B- form most commonly observed in DNA.
This results in a very deep and narrow major groove and a shallow and wide minor groove. A second consequence of the presence of the 2′- hydroxyl group is that in conformationally flexible regions of an RNA molecule (that is, not involved in formation of a double helix) it can chemically attack the adjacent phosphodiester bond to cleave the backbone.
Components of RNA:
1. Acid: Ribonucleic acid
2. Sugar: Ribose
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3. Organic bases
a) Purines: a) Adenine
b) Guanine
b) Pyrimidines: a) Cytosine
b) Uracil
4. Nucleoside: Ribonucleoside(Sugar + base)
5. Nucleotide: Ribonucleotide (Sugar + base + Phosphate)
6. Structure: Single stranded
7. Occurrence: Cytoplasm
8. Duplication: Depends on DNA.