A short Introduction to DNA and the structure of DNA. It also explains base pairing and Chargaff's rule. It informs you of who built the first model of DNA using wire and tin to show a description of how DNA looks like.

1. A Brief Introduction to
DNA

2. •What is DNA?
• DNA
stands for Deoxyribonucleic acid
(Pagdatoon, R.).
• DNA is the blue print for life (Coulter, B).
• It carries all the genetic material for all
living organisms.
• A DNA molecule is extremely long and
is tightly packed together and
wrapped onto hitsones (Coulter, B).

3. •Who described the structure of DNA?
• Watson and Crick were the first to
identify the structure of
deoxyribonucleic acid (emilydonsisk)
• Watson and Crick were British scientists
that used tin and wire to build the first
model representing the structure of
DNA.
• They illustrated that the DNA structure is
a long double helix structure
(Pagdatoon, R).

4. •A structure of DNA.

5. •Explaining the double helix.
• The
DNA structure is formed in a twisted
ladder with the outside compiled from
the sugar-backbone phosphate.
• It moves in an antiparallel direction
from 5’ to 3’ (Pagdatoon, R).
• The complimentary bases are stabilized
by hydrogen bases (guest83e221c).

6. •DNA
•A
DNA and an RNA molecule is a
polymer of nucleotides.
Each nucleotide consists of:
• Nitrogenous base which are Adenine,
Guanine, Cytosine and Thymine which
is in DNA and Uracil which is in RNA
(pagdatoon, Rizha.).
• Phosphate group
• Sugar – DNA consists of Deoxyribose
sugar and RNA consists of Ribose sugar.

7. (Teama, Hassan, S.).

8. •Understanding the nitrogenous bases.
The nitrogenous bases are grouped
according to their chemical structures
(Teama, Hassan, S.).
• There are two structures that the bases are
grouped under.
• Pyrimidine structure: this is a single ring
structure. Cytosine, thymine or uracil have
a pyrimidine structure (emilydonsisk).
• Purine structure: this is a double ring
structure. Adenine and Guanine have a
double ring (emilydonsisk).
•

9. •Explaining the complimentary bases in
DNA.
• In DNA Chargaff developed a rule
which was:
• Within a structure of DNA, the total
amount of adenine will always be
equal to the total number of thymine.
• And the total number of guanine will
always be equal to the total number of
cytocine.

10. •DNA base pairing.
• In
DNA, Adenine will pair to Thymine
with two hydrogen bonds pairing them.
• Guanine will pair to Cytocine with three
hydrogen bonds pairing them.

11. •Why is DNA important?
• DNA
is important for the following
reasons:
• 1) It carries the genetic information that
gets passed down from one generation
to the next generation.
• 2) It contains the coding for proteins.
• 3) DNA is the genetic instruction guide
for life and life’s processes.
• 4) DNA is very important by being able
to replicate itself.

12. •Where is DNA located in the cell?
• Chromatin
is a comprised of DNA and
protein.
• It is found in the nucleus of a eukaryotic
cell.
• Histones which are proteins found in the
nucleus.
• The DNA strand coils around histones
forming a nucleosome.

13. •Explaining RNA in genetics.
RNA stands for ribonucleic acid
• There are various RNA that are in the cell.
• These include: (Teama, Hassan,S).
• mRNA (messenger RNA)
• tRNA (transfer RNA)
• rRNA (ribosomal RNA)
• cRNA (Catalytic RNA)
• snRNA (small nuclear RNA)
• snoRNA (small nucleolar RNA)
•

14. •Reference
•
•
Salwa Hassan Teama M.D.
Molecular Biology Department / Medical Research Center
Ain ShamsUniversity / Cairo / Egypt
http://www.slideshare.net/salhas/introduction-to-molecular-biology
Pagdatoon, Rizha C. Penamante, Keysean M. AAPD2F.
http://www.slideshare.net/rizhapagdatoon/dna-structure-dnareplication
•
http://www.slideshare.net/emilydonsisk/dna-notes-8673498#
•
http://www.slideshare.net/brucecoulter/unit-2-notes-7346764
•
Biology: Concepts & Connections, sixth Edition Campbell, Reece,
Taylor, Simon, and Dickey http://www.slideshare.net/guest83e221c/10lecture-presentation