ribonuclic Acid

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2. Structure & Types of RNA
Presented by :-
Ribonucleic Acid
Syed Dawood Shah
 Mirpur University Of Science And Technology Azaad Kashmir Pakistan
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3. Contents
1. Discovery of RNA
3. Structure of RNA
4. The Nucleotide: RNA
2. What is RNA?
5. Shapes of RNA
6. Types of RNA?
7. Difference between DNA & RNA?
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4. Discovery of RNA
 Swiss biochemist Friedrich Miescher (1844–
1895) in 1869 separated the nucleus from the
other parts of the cell and isolated phosphorus–
containing nucleic acid.
 It was later found that there were two kinds of
nucleic acids
 One type of nucleic acid was obtained from
animal glands and later called DNA
 the other type, obtained from yeast cells, was
called RNA.
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5. Discovery of RNA
 In the 1940s biochemists realized that both DNA
and RNA are present in all living cells.
 DNA is present only in the nucleus of the cell,
RNA is found in both the nucleus as well as the
cytoplasm.
 American chemist Marshall Nirenberg (1927–)
was later credited with translating the code of life
and was awarded the Nobel Prize in 1968.
 He demonstrated that RNA could be
translated into protein.
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6. What is RNA?
 RNA-stands for ribonucleic acid
 is a polymeric molecule made up of one or more nucleotides.
 A strand of RNA can be thought of as a chain with a nucleotide at
each chain link.
 Each nucleotide is made up of a base (adenine, cytosine,
guanine, and uracil, typically abbreviated as A, C, G and U), a
ribose sugar, and a phosphate.
 DNA and RNA form the fundamental building blocks of the universal
genetic code.
 They can form complex structures which interact with proteins, other
nucleic acids, and even small regulatory molecules.
 RNA can even play a role as an enzyme (so-called ribozymes) which
can directly catalyse chemical reactions and regulate genetic
expression.
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7. Structure of RNA
 Ribonucleic acid (RNA) is a biologically important
type of molecule that consists of a long chain of
nucleotide units. Each nucleotide consists of a
nitrogenous base, a ribose sugar, and a phosphate.
 SUGAR
• Ribose
 Phosphate group
 Nitrogen containing base
• Adenine
• Guanine
• Cytosine
• Uracil
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8. Structure of RNA
 The structure of RNA nucleotides is
very similar to that of DNA nucleotides
 DNA and RNA play very different roles
from one another in modern cells.
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9. THE NUCLEOTIDE: RNA
OH
O=P-O-5
CH2 BASE
OH O
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C 1
C
H H H H
3
C 2
C
OH 0H
Adenine
Guanine
Cytosine
Uracil
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10. Shapes of RNA
RNA comes in a variety of different shapes as displayed below:
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11. Types of RNA
Messenger RNA (mRNA)
carries information from
DNA to the ribosome
Transfer RNA (tRNA)
involved in the process of translation
Ribosomal RNA (rRNA)
RNA TypesRNA Types
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12. Messenger RNA (mRNA)
 Messenger RNA (mRNA) carries
information about a protein sequence
to the ribosomes, the protein synthesis
factories in the cell
 It is coded so that every three
nucleotides (a codon) correspond to
one amino acid
 In eukaryotic cells, once precursor
mRNA (pre-mRNA) has been
transcribed from DNA, it is processed
to mature mRNA.
 This removes its introns—non-
coding sections of the pre-mRNA
 The mRNA is then exported from
the nucleus to the cytoplasm, where
it is bound to ribosomes
and translated into its
corresponding protein form with the
help of tRNA
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13. Ribosomal RNA (rRNA)
 Ribosomal RNA (rRNA) is the catalytic
component of the ribosomes
 Eukaryotic ribosomes contain four
different rRNA molecules: 18S, 5.8S,
28S and 5S rRNA
 Three of the rRNA molecules are
synthesized in the nucleolus, and one
is synthesized elsewher
 . In the cytoplasm, ribosomal RNA and
protein combine to form a
nucleoprotein called a ribosome
 The ribosome binds mRNA and
carries out protein synthesis
 Several ribosomes may be attached to
a single mRNA at any time.
 Nearly all the RNA found in a typical
eukaryotic cell is rRNA.
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14. TransferRNA (tRNA)
 Transfer RNA (tRNA) is a small
RNA chain of about 80 nucleotides
 It transfers a specific amino acid
to a growing polypeptide chain at
the ribosomal site of protein
synthesis during translation
 It has sites for amino acid
attachment and
an anticodon region
for codon recognition that binds to
a specific sequence on the
messenger RNA chain through
hydrogen bonding
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15. Difference Between DNA
and RNA
 ribose sugar backbone in RNA has a hydroxyl (-
OH) group that DNA does not.
 DNA uses the base thymine (T) in place of uracil
(U).
 DNA is double-stranded, RNA is a single-
stranded molecule in most of its biological roles
and has a much shorter chain of nucleotides.
 DNA contains ''deoxyribose'', RNA contains
''ribose'' (there is no hydroxyl group attached to
the pentose ring in the 2' position in DNA).
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