2. 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. These are the largest
and the most complex organic molecules.
3. Frederic Miesher a swiss scientist in 1869, isolated an
acidic compound from the nuclear material of SALMON sperms, and
named it as NUCLIEN which is now called NUCLEIC ACID.
5. Nucleic acid Nucleotides Phosphoric acid Nucleosides Sugar
Ribose or deoxyribose Purine Guanine and Adenine Pyrimidine base
Cytosine, uracil or thymine
6. The sugar in nucleotide, and so in nucleic acids , is a
PENTOSE. In RNA and its nucleotide the sugar is RIBOSE, whereas in
DNA and its nucleotide it is DEOXYRIBOSE. The prefix deoxy - means
without oxygen . Nucleotides can be hydrolyzed to yield nucleosides
and phosphoric acid.
7. The Sugars
8. 9 Two Kinds of Bases Pyrimidines are single ring bases.
Purines are double ring bases. C C C C N N O N C C C C N N N N N
C
10. 11 C C C C N N O N C C C C N N O N N N C Hydrogen Bonds The
bases attract each other because of hydrogen bonds. Hydrogen bonds
are weak but there are millions and millions of them in a single
molecule of DNA. The bonds between cytosine and guanine are shown
here with dotted lines
11. 12 Hydrogen Bonds, cont. When making hydrogen bonds,
cytosine always pairs up with guanine Adenine always pairs up with
thymine Adenine is bonded to thymine here C C C C N N O O C
12. Nucleosides
13. Nucleosides Pyrimidine Purine Nucleoside: a compound that
consists of D-ribose or 2-deoxy-D- ribose (monosaccharide)
covalently bonded to a nucleobase by a -N-glycosidic bond Covalent
linkage forms between N9 of purines or N1 of pyrimidines to C1
(anomeric carbon of ribose or 2-deoxyribose)
14. Phosphate group Negatively charged at neutral pH Typically
attached to 5 position Nucleic acids contain one phosphate per
nucleotide
15. Monomers nucleotides, are made up of three parts: (a)
Phosphate (phosphoric acid) (b) N-base (Nitrogenous base) (c) Sugar
~ ribose or deoxyribose
16. Nucleotides Phosphat e Pentose Sugar Nitrogeno us Base
17. Polynucleotides
18. Nucleotide monomers are joined by 3-5 phosphodiester
linkages to form nucleic acid (polynucleotide) polymers
19. Two types of nucleic acid are found Deoxyribonucleic acid
(DNA) Ribonucleic acid (RNA) BY:- YOGESH MALANI
20. BY:- YOGESH MALANI
21. BY:- YOGESH MALANI
22. DNA consists of two molecules that are arranged into a
ladder-like structure called a Double Helix. A molecule of DNA is
made up of millions of tiny subunits called Nucleotides.
23. G G A T T A A C T G C A T C
24. 1 structure: the order of bases on the polynucleotide
sequence; the order of bases specifies the genetic code 2
structure: the three-dimensional conformation of the polynucleotide
backbone = double helix structure 3 structure: supercoiling 4
structure: interaction between DNA and proteins
25. DNA - 3 Structure
26. Four stranded form of DNA (quadruplex DNA) Role in
regulating and stabilizing telomeres and in regulation of gene
expression Small molecules such as porphyrins and anthraquinones
present, to stabilize the structure
27. Structural features of A-, B-, and Z- DNA Type A-DNA B-DNA
Z-DNA Helical sensesright handed right handed left handed Diameter
() ~26 ~20 ~18 Base pairs/turn 11 10 12 Major groove narrow/deep
wide/deep Flat Minor groove wide/shallow narrow/deep
narrow/deep
28. Properties of Nucleic Acids: Nucleic acids are insoluble in
alcohol, slightly soluble in cold water, but readily dissolved in
hot water and dilute alkalies, forming alkali salts. They are
precipitated by HCL and by excess of acetic acid. Feulgen Test
differentiates the DNA from RNA, if the deoxyribose sugar is
present, a red color is produced with the dye. Ribose sugar do not
exhibit this reaction. Hydrolysis of nucleic acids gives
nucleotide, which can be considered the units that make up the
polymer.
29. 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.