DNA and RNA types and functions

1. DNA &RNA TYPES AND
FUNCTION
Subhananthini Jeyamurugan,
18py17, M.Sc., microbiology.
Ayyanadar Janaki ammal
college Sivakasi.

2. • There are two kinds of nucleic acids in cells:
1) ribonucleic acids (RNA)
2) deoxyribonucleic acids (DNA)
• Both RNA and DNA are polymers built from monomers
called nucleotides.
• A nucleotide is composed of: – a base, a
monosaccharide, and a phosphate.
NUCLEIC ACIDS

3. Nucleic Acids
• made up of nucleotides
• found in all living cells
except RBC
• deoxyribonucleic acid
(DNA) and ribonucleic acid
(RNA)
• DNA is in the nucleus
• RNA is in the cytoplasm
• function in the storage
and transmission of
genetic material •And
control and direct all
protein synthesis

4. -each nucleotide contains
1) a sugar 2) a base 3) phosphoric acid
unit

5. BASES IN NUCLEIC ACIDS
There are two types of bases such as
Purines and Pyrimidines. Purines are
Adenine and Guanine. Pyrimidine is are
cytosine, thymine and uracil.
Bases for DNA:
A- Adenine, G- Guanine,
C-Cytosine and T - Thymine
Bases for RNA:
A- Adenine, G- Guanine,
C-Cytosine and U- Uracil

6. PURINE AND PYRIMIDINE
STRUCTURE
Purines Pyrimidine

7. FORMULATION OF NUCLEICACID
1. Altering phosphate, sugar molecules form the backbone.
2. Phosphate and sugar forms an ester bond with the removal of water.
3. The sugar bonds with a base, forming tertiary amine, with the removal
of water.

8. DNA AND RNA
STRAND
The sequence of the
bases in DNA or RNA
form the Primary
Structure.

9. STRUCTURE
OF DNA

10. THE
NUCLEOTID
E BASES
ALIGN THE
DNA

11. DNA STRUCTURE
Secondary structure: The ordered arrangement of
nucleic acid strands.
 the double helix model of DNA secondary structure was
proposed by James Watson and Francis Crick in 1953.
Double helix:
 A type of secondary structure of DNA in which two
polynucleotide strands are coiled around each other in a
screw- like fashion.

12. WATSON AND CRICK

13. THE DNA DOUBLE HELIX
3D structure of a DNA
double helix.

14. DNA DOUBLE HELIX
Like a spiral stair case: the
phosphate sugar backbone
represents the hand rail. The
bases represent the steps.
Hydrogen bonding presents
between the bases
For DNA:
A bonds with T
C bonds with G
For RNA:
A bonds with U
C bonds with G

15. BASE PAIRING

16. WHAT IS HISTONES?
DNA is coiled around proteins is called as Histones.
Histones are rich in the basic amino acids Lys and Arg,
whose side chains have a positive charge.
The negatively- charged DNA molecules and positively
charged histones attract each other and form units called
nucleosomes.

17. WHAT IS NUCLEOSOME?
 A core of eight histone molecules around which the
DNA helix is wrapped.
 Nucleosomes are further condensed into chromatin.
Chromatin fibers are organized into loops, and the
loops into the bands that provide the super structure
of chromosomes.

18. CHROMOSOMES

21. To accommodate the
large amount of genetic
material, DNA in the
nuclei cells is coiled
around proteins called
Histones.

22. DNA and RNA
• The three differences in structure
between DNA and RNA are:
– DNA bases are A, G, C, and T; the RNA
bases are A, G, C, and U.
– The sugar in DNA is Deoxy ribose; in
RNA it is ribose. – DNA is always double
stranded; there are several kinds of RNA,
most of which are single-stranded.

23. RNA
RNA molecules are classified according to their structure and function.

24. WHAT IS GENES?
 A Gene is a segment of DNA that carries a
base sequences that directs the synthesis of a
particular protein, tRNA or mRNA.
There are many genes in one DNA molecule.

25. WHAT IS INTRONS AND EXONS?
Exons
A section of DNA that,
when transcribed,
codes for a protein or
RNA.
Introns
A section of DNA that
does not code for
anytihng functional.

26. STRUCTURE OF TRANSFER RNA

28. TRANSFER RNA
 Each tRNA is specific for only one amino acid.
 an amino acid binds to an OH group of the Suitable tRNA by an Ester
bond.
 At the opposite end of the tRNA molecule is a codon recognition
site.
 The codon recognition site is a sequence of three bases called an
anticodon.
 This triplet of bases aligns it self in a complementary style to the
codon triplet on mRNA

29. RNA IN TRANSLATION
 mRNA, rRNA, and tRNA all participate in translation.
Protein synthesis takes place on ribosomes.
A ribosomes dissociates into larger and a smaller body.
In higher organisms, the larger body is called a 60S ribosomes:
the smaller body is called a 40S ribosome.
 together the 40S and 60S ribosomes form a unit on which mRNA
is stretched out.
 Triplets of bases on mRNA are called codons.
 The 20 amino acids are then brought to the mRNA ribosome
complex, each amino acid by its own particular tRNA.

30. TRANSLATION
 Process whereby a base sequences of mRNA
is used to create a protein
 The m RNA leaves the nucleus and binds
with ribosomes in the cytoplasm.
 Transfer RNA (tRNA) contains and
anticodon, which is a 3 bases sequence that
is complementary to the codon on the mRNA
 tRNA also carries an amino acid
 The codon of the mRNA determines the
amino acid sequence.

31. 3D STRUCTURE
OF THE
TRANSFER RNA

32. PROTEIN SYNTHESIS

33. THANK YOU