1.
DNA
Structure

2.
DNA - Deoxyribonucleic Acid
•Found in nucleoid of prokaryotic cells
•Found in the nucleus of all eukaryotic cells
•In mitochondria (mtDNA)
•In chloroplasts (ctDNA)
•Different segments along the DNA are
genes
• Genes - determine body function and
physical characteristics
• Genes are located on chromosomes.
• Chromosomes are made of DNA & proteins

3.
Simplified Nucleotide Model
S
P
B
Draw & Label

4.
Nitrogenous Bases of DNA

5.
Nitrogen Bases
•Adenine
•Guanine
•Thymine
•Cytosine
Purines
Pyrimidines

6.
STRUCTURE OF DNA
• Double stranded
– helix (twisted, curved)
– Right-handed twist

7.
DNA - Double Helix Structure
1) Sides of the ladder are made up
of sugar and phosphates
2) Nitrogen bases stick out from the
sides of the ladder (rungs)
3) When the two sides (chains) of the
ladder are connected, it’s a complete
DNA molecule

8.
DNA - Double Helix
4) Adenine bonds with Thymine*
5) Guanine bonds with Cytosine*
6) Hydrogen bonds connect the bases
*see next slide

9.
Edwin Chargaff – 1947
Studied DNA in various species
Nitrogen bases are proportionate within a species
Ratio of bases are various between species
•Adenine and Thymine were found in proportionate amounts
•Cytosine and Guanine were found in proportionate amounts
Chargaff’s Rules

10.
S
P
P
P
PP
P
S
S
S
S
S
T
T
C
Draw DNA

11.
Bases
Side/backbone

12.
Nucleotide

13.
DNA Structure

14.
DNA Structure

15.
3.4

16.
0.34

17.
1

18.
Base pair

19.
deoxyribose
deoxyribose

20.
phosphate

21.
hydrogen
bonds

22.
5’
5’

23.
3’
3’