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]
Free CLEP Study Guide, CLEP Test Papers, CLEP Practice papers, CLEP Test pattern and general information, Find CLEP exam information and resource, material free at Tutorsglobe.com
The objectives of inter-firm comparison are: Each member-unit can try to enhance its efficiency while on comparison with other member-firms it comes to make out about its weak points.
Filters tutorial all along with the key concepts of Filter topology, Passive topologies, Active filter, Single element filter, L-FILTER, Multiple Element Filters, roles of capacitor and inductor, Single Element Topology
theory and lecture notes of nature of electricity having key concepts of electric field and electromotive force, current, the nature of electricity, electric charge, coulomb’s law, energy bands, potential and voltage. tutorsglobe offers homework help, assignment help and tutor’s assistance on nature of electricity.
www.tutorsglobe.com offers chemical bonding and valence homework help, chemical bonding and valence assignment help, online tutoring assistance, organic chemistry solutions by online qualified tutor's help.
tutorsglobe.com innate immunity assignment help-homework help by online immunology tutors
www.tutorsglobe.com offers aldol reaction homework help, aldol reaction assignment help, online tutoring assistance, organic chemistry solutions by online qualified tutor's help.
Power Amplifiers tutorial all along with the key concepts of Categorization of power amplifiers, Power amplifier specifications, Power Gain, Output Dynamic Range, Practical limitations in power amplifiers, Noise Figure, Linearity, Bandwidth
Flip-Flops tutorial all along with the key concepts of RS Flip-flop, Setting Flip-flop, Resetting or Clearing Flip-flop, Clocked RS Flip-flop, Clocked D Flip-flop, D Latch, Clocked JK Flip-flop
tutorsglobe.com method of computing cost of capital assignment help-homework help by online cost of capital tutors
tutorsglobe.com stages of cell mediated graft refusal assignment help-homework help by online blood group typing tutors
the role of the chairman is to direct the board of directors and the role of the chief executive officer (CEO) is to direct the management team.
tutorsglobe.com interphase assignment help-homework help by online mitotic cell cycle tutors
Operating Point tutorial all along with the key concepts of Biasing circuit, Base-collector junction, base-emitter, forward-biased, reverse-biased, Cut-off-Open Circuit Condition, Saturation-Short Circuit Condition, Active Region, p-region voltage, n-region
Waste Management tutorial all along with the key concepts of Waste disposal, Waste management resources, Methods for dumping off waste, Incineration, Methods for recycling, Biological reprocessing, Recovery of Energy
1936121
Questions Asked
3689
Tutors
1465818
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!