1. Subject :
PRESENTATION OF
MOLECULAR CELL
BIOLOGY
Submitted To: Dr. Ahsan Anjum
Submitted by: Azhar Manzoor
Roll no:2022-uam-5213
Topic : DNA & Its Replication
2. TOPIC: DNA & REPLIACTION
DNA :
DNA is a group of molecules t h a t is responsible for
carrying and transmitting the hereditary materials or
the genetic instructions from parents t o offsprings.
FUNCTION:
DNA is the information molecule. It stores
instructions for making other large molecules, called
proteins. These instructions are stored inside each of
your cells, distributed among 46 long structures
called chromosomes. These chromosomes are made
up of thousands of shorter segments of DNA, called
genes
3. FORMS OF DNA:
desiccation. Protein binding
during ex t rem e c ondit ions suc h as
also
rem oves t he solvent from DNA, and t he
DNA takes an A form.
There are Three major forms of DNA
A- Form DNA
B- Form DNA
Z-Form DNA
A-Form DNA
It is a right-handed double helix similar
to the B-DNA form. Dehydrated DNA
takes an A form that protects the DNA
4. FORMS OF DNA:
There are Three major forms of DNA
A- Form DNA
B- Form DNA
Z-Form DNA
B-Form DNA
This is the most common DNA
conformation and is a right-handed helix.
The majority of DNA has a B type
conformation under normal physiological
conditions.
5. FORMS OF DNA:
There are Three major forms of DNA
A- Form DNA
B- Form DNA
Z-Form DNA
Z-Form DNA
Z-DNA is a left-handed DNA where the
double helix winds to the left in a zig-zag
pattern.It is found ahead of the start site
of a gene and hence, is believed to play
some role in gene regulation.
7. DNA REPLICATION:
DNA replic at ion is an im port ant
proc ess t hat oc c urs during
division. It is also known as
c ell
sem i-
conservative replication, during which
DNA makes a copy of itself.
8. DIFFERANCE BETWEEN LEADING & LAGGING STRAND
LEADING STRAND:
The leading strand is a single DNA strand
that, during DNA replication, is replicated in
the 3' – 5' direction (same direction as the
replication fork). DNA is added t o the leading
strand continuously, one complementary base
at a time.
LAGGING STRAND:
The lagging strand is a single DNA strand
that, during DNA replication, is replicated in
the 5′ – 3′ direction (opposite direction t o
the replication fork)
