Nucleic acid play an important role in transmission of hereditary characteristics and biosynthesis of proteins. DNA and RNA * CONTENTS  Introduction to Nucleic acids History of Nucleic acids Structure of Nucleic acids Description of Nucleic acids Chemical structure of DNA and RNA Classifications of Bases Sites of Nucleic acids Names of Nucleosides and Nucleotides Conclusion References * Structure of Nucleic acids  NA structure is often divided into four different levels: Primary structure Secondary structure Tertiary structure Quaternary structure * Primary structure: consists of a linear sequence of nucleotides that are linked together by phosphodiester bond. Nucleotides consists of 3 components: Nitrogenous base 5-carbon sugar One or more phosphate groups * Secondary structure This is the set of interactions between bases. In DNA double helix, the two strands of DNA are held together by hydrogen bonds. The nucleotides on one strand base pairs with the nucleotide on the other strand. The secondary structure is responsible for the shape that the nucleic acid assumes. * Tertiary structure This is the locations of atoms in three-dimensional space, taking into consideration geometrical and steric constraits. A higher order than the secondary structure in which large scale folding in a linear polymer occurs and the entire chain is folded into a specific 3-dimensional shape. * Quaternary structure This is similar to that of protein quaternary structure. Although some of the concepts are not exactly the same. QS refers to a higher level of organization of nucleic acids moreover, it refers to the interactions of the nucleic acids with other molecules. * NNuucclleeiicc AAcciiddss Nucleic acids are molecules that store information for cellular growth and reproduction * There are two types of nucleic acids: - deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) * These are polymers consisting of long chains of monomers called nucleotides A nucleotide consists of a nitrogenous base, pentose sugar and a phosphate group. * DNA and RNA are nucleic acids, long, thread-like polymers made up of a linear array of monomers called nucleotides All nucleotides contain three components: 1. A nitrogen heterocyclic base 2. A pentose sugar 3. A phosphate residue * Ribonucleotides have a 2’-OH Deoxyribonucleotides have a 2’-H * Bases are classified as Pyrimidines or Purines * Nucleus Cytoplasm replication DNA transcription RNA (mRNA) translation Proteins * reverse transcription messenger RNA (mRNA) transfer RNA (tRNA) ribosomal RNA (rRNA) * Names of Nucleosides and Nucleotides * X-ray diffraction patterns produced by DNA fibers Rosalind Franklin and Maurice Wilkins * 1962 Nobel Prize in Physiology or Medicine for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material" James Watson Francis Crick Maurice Wilkins

1. Nucleic Acids
BY-Jay
Parekh

2. Nucleic Acids
• Nucleic acid are long chain polymers of
nucleotides present in nuclei of cell, so they are
also called polynucleotide. They play an
important role in transmission of hereditary
characteristics and biosynthesis of proteins.

3. Two Types of Nucleic Acids
DNA RNA
• The sugar present in DNA
is β-D-2 Deoxyribose.
• DNA contains cytosine and
thymine as pyrimidine
bases.
• DNA has a double stranded
-helix structure.
• DNA molecular mass may
vary from 6x106-16x106 u.
• The sugar present in RNA
is β-D Ribose.
• RNA contains cytosine and
uracil as pyrimidine bases.
• RNA has a single stranded
-helix structure.
• RNA molecular mass
ranging from 20,000to
40,000 u.

4. The Chemical Composition of
Nucleic Acids
I. Pentose sugar
-Phosphoric acid
-Nitrogenous bases
II. Deoxyribonucleic Acid (DNA)
III. Ribonucleic Acid (RNA)

5. Hydrolysis of DNA and RNA
• Complete hydrolysis of DNA (or RNA) yields a
pentose sugar, phosphoric acid and nitrogen
containing heterocyclic compounds.

6. • DNA contains four bases viz. adenine (A),
guanine (G), cytosine (C) and thymine (T).
Adenine
Thymine
Guanine Cytosine

7. • RNA also contains four bases are adenine (A),
guanine (G), cytosine (C) and uracil (U).
Adenine
Guanine Cytosine

8. Structure of Nucleic Acid
• A unit formed by the attachment of a base to 1′ position
of sugar is known as nucleoside.
• When nucleoside is linked to phosphoric acid at 5′-
position of sugar moiety, we get a nucleotide.

9. • Nucleotides are joined together by phosphodiester
linkage between 5′ and 3′ carbon atoms of the pentose
sugar.

10. • A simplified version of nucleic acid chain.
• Information regarding the sequence of nucleotides in the
chain of a nucleic acid is called its primary structure.

11. DNA
• James Watson and Francis
Crick gave a double strand
helix structure for DNA.
Two nucleic acid chains are
wound about each other and
held together by hydrogen
bonds between pairs of
bases.
• Adenine forms hydrogen
bonds with thymine whereas
cytosine forms hydrogen
bonds with guanine.

12. DNA Fingerprinting
• It is known that every individual has unique
fingerprints. These occur at the tips of the fingers
and have been used for identification for a long time
but these can be altered by surgery.
• A sequence of bases on DNA is also unique for a
person and information regarding this is called DNA
fingerprinting. It is same for every cell and cannot be
altered by any known treatment.

13. DNA fingerprinting is now used :
• In forensic laboratories for identification of criminals.
• To determine paternity of an individual.
• To identify the dead bodies in any accident by comparing
the DNA’s of parents or children.
• To identify racial groups to rewrite biological evolution.

14. RNA
• In secondary structure of RNA, helices are present
which are only single stranded. Sometimes they fold
back on themselves to form a double helix structure.
RNA molecules are of three types and they perform
different functions. They are named as messenger
RNA (m-RNA), ribosomal RNA (r-RNA) and
transfer RNA (t-RNA).

15. Biological Functions of Nucleic Acid
• DNA is the chemical basis of heredity and may be
regarded as the reserve of genetic information.
• The proteins are synthesized by various RNA molecules
in the cell but the message for the synthesis of a
particular protein is present in DNA.
• DNA is exclusively responsible for maintaining the
identity of different species of organisms over millions of
years.

16. Thank You!