DNA Structure

3. • Classified as a Nucleic Acid.Nucleic Acid.
• Long, double stranded molecule made
up of monomers know as nucleotides.nucleotides.
• DNA

4. • Basic unit of DNA.
• Three Parts
Deoxyribose sugar
Phosphate group
Nitrogen base

5. Many nucleotides
are joined together
to make a DNA
molecule.

6. There are four different bases found in DNA.
Because each base contains at least two nitrogen
atoms, they are called nitrogenous bases.nitrogenous bases.

7. There are two
classes of bases:

8. DNA consists of two polynucleotidepolynucleotide chains
wound around each other to form a double
helix. The two chains are held together by
complementary base pairing;complementary base pairing; that is, hydrogenhydrogen
bonding between A and T bases, and betweenbonding between A and T bases, and between
G and C bases on the two strandsG and C bases on the two strands..

9. 1) a double-stranded helix
2) of uniform diameter
3) twisting to the right

10. 4) the two strands
running in opposite
directions

11. 5′
5′
3′
3′
Covalent sugar
phosphate/
phospho diester
bonds
hydrogen
bonds

12. A DNA chain consists of
nucleotides joined by
covalent sugar phosphate/covalent sugar phosphate/
phospho diesterphospho diester bonds,
between phosphate and
sugar.
This makes up the sides of the
DNA “ladder”.

13. Complementary baseComplementary base
pairingpairing involves specific
hydrogen bonding
between A and T bases
(two bonds), and between
G and C bases (three
bonds).
These paired bases
form the rungs of
the DNA “ladder”.

14. DNA is the Master Molecule of
diversity. Its simple structure holds
the key to millions of different genetic
codes for all of the species of life on
The Earth.