DNA Structure

(This slideshare is being made for practice only - do not use this for educational purposes. Original Source, FCPS ESOL department.)

1. DNA

2. DNA Structure
•DNA: Deoxyribonucleic acid
•Each chromosome is made of one
piece of DNA
46 chromosomes = 46 pieces of DNA
•DNA:
– 2 strands connected
– Shape of a twisted ladder
– The twisted ladder is called a
DOUBLE HELIX

3. Function of DNA:
-Stores genetic information: genetic
information makes you what you are
- Controls all cell and body activities

4. Chromosome Structure
Section 12-2

5. Nucleotides:
Basic building blocks of DNA
Nucleotides are made up of:
•Deoxyribose: a sugar
•Phosphate
•Nitrogen Base:
– Adenine = A
– Guanine = G
– Cytosine = C
– Thymine = T

6. Nucleotides and Pairing: A-T C-G
The sugar and
phosphate make the
sides or rails of the
double helix (ladder)

7. Structure of DNA
Section 12-1

8. DNA complementary strands
•The 2 strands of DNA are represented by the
sequence of nitrogen bases
A T C G A A C G T T A
T A G C T T G C A A T
•Write the complementary DNA strand:
A T C G G G T T A A C G T A T C C

9. The People Behind
1. 1949: Erwin Chargaff
discovers the rules of
base pairing
A-T C-G

10. • 1952: Rosalind Franklin determined
that the DNA molecule was a coiled
spiral.
They used a technique called X-ray diffraction

11. 3. 1953: James
Watson (USA)
and Francis
Crick (UK)
determine the
exact structure
of DNA.
•Received the
Nobel Prize in
1962

12. Nucleic Acids
•Are made of: C (carbon), H (hydrogen),
O (oxygen), N (nitrogen), P (phosphates).