CELL BIOLOGY, GENETICS, MOLECULAR BIOLOGY, EVOLUTION AND ECOLOGY (BY P.S. VERMA AND V.K AGARWAL) SARA’S PUBLICATION

2.  DNA – a polymer of deoxyribonucleotides.
 The double helix shape is sometimes
called a twisted ladder.
 It carries the genetic information.
 A double stranded combination of sugars,
phosphates, and nitrogen bases.

4.  A nucleoside consists of a nitrogenous base covalently attached to a sugar but without the phosphate group.
 A nucleotide consists of a nitrogenous base, a sugar and one to three phosphate groups.

5. STRUCTUR OF DNA
 The secondary structure of DNA is
the double helix.
 Two anti-parallel polynucleotide chains
wound around the same axis.
 Sugar-phosphate chains wrap around
the periphery.
 Bases (A, T, C, and G) occupy the
core, forming complementary A . T and
G . C Watson-Crick base pairs.
 The DNA double helix is held together
mainly by- Hydrogen bonds.

6. Structural forms of DNA

7.  Helical sense: right handed
 Base pairs: almost perpendicular to
the helix axis; 3.4 Å
 One turn of the helix: 36 Å;~10.4
base pairs
 Minor groove: 12 Å across
 Major groove: 22 Å across
 In eukaryotic calls, DNA is folded
into chrometin.
Normally hydrated DNA: B-form DNA

8. DNA Tertiary structure
 DNA double helical structure coils round
histones.
 DNA bound to histones forms
nucleosomes(10nm Fibres).
 Nucleosomes contain 146 nucleotides.
Nucleosomes
 Any of the repeating globular subunit of
chromatin that consist of a complex of DNA
and histone.
Compaction of DNA in
eukaryotic chromosome

9. Supercoiling
=
Coli over coli

13. CELL BIOLOGY, GENETICS, MOLECULAR BIOLOGY,
EVOLUTION AND ECOLOGY (BY P.S. VERMA AND V.K
AGARWAL)
SARA’S PUBLICATION
NET SOURCE- SLIDE SHARE

14. ACKNOWLEDGEMENT:
I Would Like To Acknowledge Our Department Faculties:
Mr. SHAILESH DIHORA
Miss. BANSRI
Miss. DRASHTI
For Providing Their Precious Guidance And Time