Introduction:
The association of nitrogenous bases and pentose sugars provides the compound known as nucleoside which is component of nucleotides (monomeric units of nucleic acids). Based on type of nitrogenous base and types of sugar it is liked to, different kinds of nucleotides are formed each containing its own characteristic and structure.
Definition of nucleosides:
Nucleosides are organic compounds having pentose sugars and nitrogenous base linked together by N-β-gylcosidic bond. Sugar can either be ribose sugar or deoxyribose sugar while nitrogenous bases are: Guanine, Adenine, Cytosine, Thymine or Uracil etc.
Components of nucleoside:
Components of nucleosides are essentially nitrogenous bases and pentose sugars.
Nitrogenous bases and their structures:
Nitrogenous bases present in nucleosides are either purines or pyrimidines and are given below. Purine bases contains purine ring (double ring system) while pyrimidine base contain pyrimidine ring (single ring structure).
The purine bases are:
Adenine denoted by A and has the structure:
Guanine denoted by G and has the following structure:
The pyrimidine bases are cytosine, thymine and uracil
Cytosine denoted by C and has the following structure
Thymine denoted by T and has the structure below
Uracil, denoted by U and has the structure below:
Additionally to purine bases A and G other unusual purine bases do exist and they comprise: hypoxathine, 1 methylguanine, 1 methylhypoxanthine etc. Unusual pyrimidine bases also exist and they are derived from cytosine, thymine and uracil and they comprise: 5-methylcytosine, Thiouracil etc.
Pentose sugars and their structures:
The pentose (5 carbon) sugars of nucleoides are basically ribose or (ribofuranose) 2' deoxyribose (2' deoxyribofuranose). The 2' deoxyribose sugar is found in deoxyribonucleic acid (DNA) while the ribose sugar is found in ribonucleic acid (RNA).
Linkages between pentose sugars and nitrogenous Bases in nucleosides:
In nucleosides, nitrogenous bases are joined to pentose sugar through the hemiacetal hydroxyl group on the C-1 (first carbon atom of the sugar). Generally, the purines are attached to the sugar through the N-9 nitrogen atom while pyrimidine is attached through the N-1 nitrogen atom.
Common purine and pyrimidine nucleosides and their Structures:
Purine Nucleosides:
Pyrimidine Nucleosides:
Nomenclature of nucleosides:
Nucleosides are named based on kind of ribose sugar attached to nitrogenous base and whether base present in nucleoside is the purine or pyrimidine.
All purine nucleoside names end with the suffix (-osine) added to name of purine base irrespective of whether it has ribose or deoxyribose sugar. Examples comprise: Adenosine, guanosine, deoxynadenosine and deoxyguanosine. If purine nucleoside has the deoxyribose sugar then prefix (-deoxy) is added to name of its ribonucleoide counterpart example deoxyadenosine and deoxyguanosine are deoxyribonucleosides of adenosine and guanosine respectively.
For naming of pyrimidine ribonucleoside the suffix (-idine) is added to name of base in nucleoside. Example ribonucleoside of uracil is named uridine, (-acil) of uracil is replaced by (-idine). Cytosine ribonucleoside is named Cytidine while that of Thymine is Thymidine. On other hand pyrimidine deoxyribonucleoside are named by adding the prefix 2' deoxy to name of its pyrimidine ribonucleosides counterpart like 2' deoxythymididine, 2' deoxycytidine, 2'deoxyadenosine, 2'deoxyguanosine and 2'deoxyuridrine.
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with a tutor at www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online biology tutoring. Chat with us or submit request at [email protected]
tutorsglobe.com xenon fluoride compounds assignment help-homework help by online noble gases tutors
theory and lecture notes of dc motors i all along with the key concepts of current carrying conductors in magnetic fields, force, current carrying loop in magnetic field, angle of motion, direction of current. tutorsglobe offers homework help, assignment help and tutor’s assistance on dc motors i.
Taxonomy of invertebrates tutorial all along with the key concepts of Classification of Invertebrates, Protozoa, Echinoderms, Annelids, Mollusks, Arthropods, Crustaceans, Arachnids and Insects
find out the current direction through applying right hand rule of fleming, while the mode of operation is a generator and left hand rule of fleming, while the mode of operation is a motor.
Crystal diffraction-II tutorial all along with the key concepts of Reciprocal Lattice, Ewald's Construction in the reciprocal lattice, Bragg Law in Vector Form, Brillouin Zones
tutorsglobe.com atherosclerosis assignment help-homework help by online lipid metabolism tutors
a wire’s length lying in the magnetic field and where an emf is induced is termed as a coil.
Electronic Instruments tutorial all along with the key concepts of Cathode ray oscilloscope, Cathode Ray Tube, Basic Oscilloscope, Input to Amplifier of Vertical Plate, Input to Amplifier of Horizontal Plate, Signal generators, Function generator, Pulse Generators, Differential-Amplifier type of EVM
tutorsglobe.com complement system assignment help-homework help by online natural immunity tutors
theory and lecture notes of transformers and faraday’s experiments all along with the key concepts of emf induced in a coil, faraday’s experiments, ideal transformer, turn ratio and current ratio. tutorsglobe offers homework help, assignment help and tutor’s assistance on theory of transformers and faraday’s experiments.
tutorsglobe.com proteins assignment help-homework help by online nutrition tutors
tutorsglobe.com laboratory diagnosis assignment help-homework help by online cryptococcus neoformans tutors
tutorsglobe.com comparison of live and killed vaccines assignment help-homework help by online vaccines tutors
tutorsglobe.com externalities-open access and public goods assignment help-homework help by online intermediate microeconomics tutors
tutorsglobe.com biology in human welfare assignment help-homework help by online botany tutors
1943723
Questions Asked
3689
Tutors
1453727
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!