2. Nucleoside, Nucleotide & Nucleic acid
p h o s p h a te
su g a r base
p h o s p h a te p h o s p h a te
su g a r base
su g a r base su g a r base
p h o sp h a te
nucleoside nucleotides
sugar b a se
nucleic acids
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4. • Deoxyribonucleotide; monomeric building
block of DNA; a phosphate group and a
nitrogenous base both bonded to deoxyribose
• Ribonucleotide; monomeric building block of
RNA; a phosphate group and a nitrogenous
base both bonded to ribose sugar
• Duplex; two complementary strands of DNA
• Mutant; genetically altered species or cell
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5. • Nucleoside; nitrogenous base bonded to ribose
or deoxyribose
• Nucleotide; monomeric building block of
RNA and DNA; a phosphate group and a
nitrogenous base both bonded to ribose or
deoxyribose
• Nucleic Acids are Polynucleotides
• Phosphodiester; two different alcohols
forming ester linkages with one phosphate ion
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6. • Replication; DNA synthesis
• Template; a section of DNA which is being
replicated or transcribed; mRNA which is
being translated
• Transcription; synthesis of RNA from DNA
• Translation; synthesis of proteins from an
RNA template
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7. Nucleotides and Nucleic Acids
• Introduction;
• Nucleic acids are macromolecules present in
all living cells in combination with protein
with high concentration of basic amino acids
to form nucleoproteins. (protamines and
histones)
• Nucleic acids compounds carrying information
-- the genetic molecules (DNA and RNA) .
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8. • The nucleic acids are of two types
• -1-deoxyribonucleic acid DNA
• -2-ribonucleic acid RNA
• DNA is present in the nuclei small amounts
present in the mitochondria
• RNA is present in the cell cytoplasm (90%)
about 10% present in the nucleolus
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9. Nucleotides
Nucleoside phosphates
• Nucleotides are monomers of nucleic acids
• The nucleotides found in cells are derivatives
of the heterocyclic highly basic, compounds,
purine and pyrimidine present in DNA and
RNA (nitrogenous bases)
Heterocyclic are ring compounds that contain
both carbon atom and non-carbon atoms --
mainly nitrogen atom.
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10. Nucleotide Structures of purine and pyrimidine
Heterocyclic ring compounds
Nitrogenous Bases
Single six-sided ring Double ring purines
pyrimidinesC4H4N2 (six- and five-sided)
C5H4N4
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11. Types of nucleotide bases
• There are five major bases found in cells.
• The derivatives of purine are called adenine
and guanine (found in both DNA & RNA) ,
• the derivatives of pyrimidine are called
thymine, cytosine and uracil.
•
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12. The derivatives of purine ; adenine and guanine (found in both
DNA & RNA) 1-Adenine 6-aminopurine, 2-Guanine 2-amino-
6-oxypurine
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13. the derivatives of pyrimidine are thymine, cytosine and uracil.
Cytosine- 2-oxy-4-aminopyrimidine, Uracil-n2,4-
dioxypyrimidineThymine-2,4-dioxy-, 5-methyl
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14. • The common abbreviations used for these five
bases are, A, G, T, C and U.
• Cytosine & Uracil in RNA
• Cytosine and thymine in DNA
• The nucleotide uridine is never found in DNA
• thymine is almost exclusively found in DNA.
• Thymine is found in tRNAs but not rRNAs nor
mRNAs
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15. Nucleotides mainly;
Pentose sugar+ β-N-glycosidic bond+
phosphoryl group
• Derivative of purines and pyrimidines are
nucleotides----contain mainly cyclyized sugar
Pentose linked to nitrogen hetroatom by β-N-
glycosidic bond additional to phosphoryl
group esterified to hydroxy group of the sugar
(β-D-ribose or β-D-2-deoxyribose)
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16. Nucleotides mainly;
1-pentose sugar. 2-phosphate groups. 3-a
nitrogeous base
• 1-5–carbon sugar component
• Ribose
• Deoxyribose
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18. • 2-Phosphate group Attached to the sugar's
5' carbon with a phosphodiester bond
• 3-Nitrogen Base component attached to the
sugar's 1'carbon.
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19. Functions of Nucleotides
• Components of nucleic acids (which are long
chains of nucleotides)
• ATP (Adonosine TriPhosphate) is central to
energy metabolism
• GTP (Guanosine TriPhosphate) drives protein
synthesis
• CTP (Cytidine Triphosphate) drives lipid
synthesis
• UTP (Uridine Triphosphate) drives carbohydrate
metabolism
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20. • Energy transport coenzymes (NAD+, NADP+,
FAD+)
• Chemical intracellular messengers (e.g., Cyclic
AMP, a cyclic nucleotide that carries messages
from the cell membrane to molecules within
the cell, to stimulate essential reactions.
regulators of cellular metabolism and
reproduction )
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21. Nucleosides
• Nucleoside consist of purine and pyrimidine
bases and a sugar β-D-ribose or β-D-2-
deoxyribose linked through a covalent β-N-
glycosidic bond
• Therefore Nucleosides are Formed by Joining
a Nitrogenous Base to a Sugar
• Base is linked via a β-N-glycosidic bond
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22. β-N-glycosidic bond linked nitrogen-9 of the purine
base or nitrogen-1 of the pyrinidine base with
carbon1 of pentose sugar
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23. • The nucleosides of A, G, C,T, U are named
• Adenine ---Adenosine
• Guanine ----Guanisine
• Cytosine ----Cytidine
• Thymine ----Thymidine
• Uracil -----Uridine
• Purine nucleosides end “osine”
• Pyrinidine ends in “idine”
• Ribose sugar produced; ribonucleoside
• 2-deoxyribose sugar produced;
deoxyribonucleosides
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24. • The nucleosides in DNA are called;
deoxyadenosine,
• deoxyguanosine,
• deoxycytidine, and thymidine,
• the nucleosides in RNA are called;
• adenosine, guanosine, cytidine, and uridine.
• If the base is a purine, then the N-9 (nitrogen) is
bonded to the C-1' (carbon) of the sugar.
• If the base is a pyrimidine, then the N-1 is
bonded to the C-1' of the sugar.
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27. The base can exist in 2 distinct orientations about the
N-glycosidic bond. These conformations are identified
as, syn and anti. It is the anti conformation that
predominates in naturally occurring nucleotides
Syn- adenosine anti-adenosine
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28. Nucleotides and nucleosides that are not part of
DNA or RNA
the importance of free nucleotide
• Some nucleotides are not part of DNA or RNA
but still play important roles in a cell.
• cyclic adenosine monophosphate (cAMP) is an
intracellular signal: it communicates
information from one part of the cell to
another.
• Other nucleotides are coenzymes, which are
molecules that help enzymes work properly
(FAD, NAD).
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29. Adenosine triphosphate (ATP)
Adenosine triphosphate (ATP) is a common
and critical energy transfer molecule. The
bonds that hold three phosphate groups to
adenosine store energy. They form when
energy is released and transfer that energy to
other places in a cell.
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31. Nucleic acid
polynucletide
• the nucleic acids are polymers of subunits of
monomers nucleotides.
• Nucleic acid; important substance that all
cellular organisms use to store their genetic
information.
• The most common nucleic acids are
deoxyribonucleic acid and ribonucleic acids
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32. The chemical linkage between nucleotide units in nucleic acids is a
phosphodiester, which connects the 5’-hydroxyl group of one nucleotide to
the 3’-hydroxyl group of the next nucleotide.
• Phosphodiester bonds are essential to all life, as
they make up the backbone of each helical strand
of DNA.
• In DNA and RNA, the phosphodiester bond is the
linkage between the 3’ carbon atom of one sugar
molecule and the 5’ catbon atom of another;
• the sugar molecules deoxyribose in DNA
• and ribose in RNA.
• Hydrolysis of phosphodiester bonds can be
catalyzed by the action of phosphodiesterases
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33. Sequences of RNA and DNA structures
The chemical linkage between monomer units in
nucleic acids is a phosphodiester
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34. phosphodiester, connects the 5’-hydroxyl group of one
nucleotide to the 3’-hydroxyl group of the next
nucleotide.
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36. classes of nucleic acids
1-Deoxyribonucleic acid DNA
• Deoxyribonucleic acid (DNA) is a
nucleic acid containing the genetic
instructions used in the development
and functioning of all known living organisms
(with the exception of RNA viruses).
• The DNA segments carrying this genetic
information are called genes .
• Genes (specific regions of DNA molecules)
contain the hereditary information of an
organism.
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37. • When organisms reproduce The code is read by
copying stretches of DNA into the related nucleic acid
RNA in a process called transcription.
• Within cells DNA is organized into long structures
called chromosomes, (packaged form of the DNA).
• During cell division these chromosomes are duplicated
in the process of DNA replication, providing each cell
its own complete set of chromosomes (46).
• Within the chromosomes, chromatin proteins such as
histones compact and organize DNA.
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38. DNA structure and function
• DNA structure is the well-known double helix
formed by Watson-Crick base-pairing of C
with G and A with T.
• This is known as B-form DNA, and is the
most favorable and common state of DNA;
• its highly specific and stable base-pairing is
the basis of reliable genetic information
storage.
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39. Structure of DNA
naturally occurring DNA molecules are double-
stranded
Watson-Crick model for the structure of DNA
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40. Tertiary Structure of DNA: Supercoils. Each cell
contains about two meters of DNA. DNA is “packaged”
by coiling around a core of proteins known as histones.
The DNA-histone assembly is called a nucleosome.
Histones are rich is lysine and arginine residues
Dr Siham Gritly 40
41. the Watson-Crick model
• James Watson and Francis Crick proposed a
model for the structure of DNA.
• This model predicted that DNA would exist as
a helix of two complementary antiparallel
strands, wound around each other in a
rightward direction and stabilized by H-
bonding between bases in adjacent strands.
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42. • They proposed that in any given molecule of
DNA,;-
• the concentration of adenine (A) is equal to
thymine (T)
• and the concentration of cytidine (C) is equal
to guanine (G).
• This means that A will only base-pair with T, and
C with G. According to this pattern, known as
Watson-Crick base-pairing, the base-pairs
composed of G and C contain three H-bonds,
whereas those of A and T contain two H-bonds.
This makes G-C base-pairs more stable than A-T
base-pairs.
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47. Complementarity of strands
in the DNA double helix
-Adenine (A) and thymine (T)
always pair together (A–T),
-cytosine (C) and guanine (G)
always pair together (C–G).
In other words, A and T are
complementary bases, as are C
and G.
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48. Replication of DNA as
suggested by
Watson and Crick
Replication: process
by which DNA is
copied itself
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49. Two polynucleotide strands, running in opposite directions
(anti-parallel) and coiled around each other in a double helix.
The strands are held together by complementary hydrogen-
bonding between specific pairs of bases
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51. Function of DNA
• 1-store of genetic information;
• genetic information is the source of
information for the synthesis of all protein
molecules. The information is copied or
transcribed into RNA molecules
• Proteins are then synthesized in the process
involving the translation of the RNA
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52. • 2-DNA provides the inherited information by
the daughter cell. DNA provide template for
the replication of information into daughter
DNA molecule
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53. 2-Ribonucleic acid RNA
• Ribonucleic acid RNA is a long unbranched
macromolecules consisting of nucleotides
joined by 3’ to 5’ phosphodiester bonds. It is
the same as DNA but it possesses different
characteristic
• RNA differ from DNA in that it is a single
strand do not contain regions of double helical
structure
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54. • RNA contain ribose sugar instead of 2-
deoxyribose that present in DNA
• contain four major bases
• 1-purine bases;-Adenine and Guanine
• 2-pyrimidin bases;- Cytosine and Uracil
• RNA contain Uracil instead of thymine
• RNA pairs Adenine with Uracil and Cytosine
with Guanine
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55. Structure of RNA
RNA molecules are single-stranded
RNA contain Uracil instead of thymine
RNA pairs Adenine with Uracil and
Cytosine with Guanine
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56. Ribonucleic acid (RNA) functions
• Ribonucleic acid (RNA) functions in
converting genetic information from genes into
the amino acid sequences of proteins.
RNA translates the DNA message to a format
that can be read by ribosomes, or the cellular
organelles that assemble proteins (process
known as translation).
RNA also plays a role in engage the correct
amino acids to the protein meeting sites.
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57. types of RNA
• The three universal types of RNA include
• 1-transfer RNA (tRNA), transfer RNA serves as the
carrier molecule for amino acids to be used in
protein synthesis, and is responsible for decoding
the mRNA.
• 2-messenger RNA (mRNA), messenger RNA acts
to carry genetic sequence information between
DNA and ribosomes, directing protein synthesis
• 3-ribosomal RNA (rRNA). ribosomal RNA is a
major component of the ribosome, and catalyzes
peptide bond formation.
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60. references
Murry K. Robert, Granner K. daryl, Mayes A.
peter, Rodwell W. Victor (1999). Harpers
Biochemistry. Appleton and Lange , twent fifth
edition
• A. Burtis, Edward R. Ashwood, Norbert W. Tietz
(2000), Tietz fundamentals of clinical chemistry
• Maton, Anthea; Jean Hopkins, Charles William
McLaughlin, Susan Johnson, Maryanna Quon
Warner, David LaHart, Jill D. Wright (1993).
Human Biology and Health. Englewood
Cliffs, New Jersey, USA: Prentice Hall. pp. 52–59
Dr Siham Gritly 60
61. references
• Nelson DL, Cox MM (2005). Lehninger's Principles of
Biochemistry (4th ed.). New York, New York: W. H.
Freeman and Company.
• Matthews, C. E.; K. E. Van Holde; K. G. Ahern (1999)
Biochemistry. 3rd edition. Benjamin Cummings.
• Naik Pankaja (2010). Biochemistry. 3ed edition, JAYPEE
• Maitland, Jr Jones (1998). Organic Chemistry. W
W Norton & Co Inc (Np). p. 139. ISBN 0-393-
97378-6.
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