1. mRNA
Transcription
Introduction
The Central Dogma
of Molecular Biology
Cell
Polypeptide
(protein)
Translation Ribosome
Reverse
tanscription DNA

2. DNA STRUCTURE
chemical structure of the 4 nucleotides in DNA

3. DNA STRUCTURE
 hydrogen bonded nucleotides
on opposite helices
 DNA helices are antiparallel
 carbons on sugar define
ends... 5' and 3'
 pyrimidines bond with purines
 T  A
 C  G

4. DNA STRUCTURE
 bonding is specific: pyrimidines bond with purines
 implication: means for accurate replication

5. DNA STRUCTURE
 helical structure of DNA
 major & minor groves
 10Å radius & 20Å diameter
 3.4Å between nucleotide
base pairs
 34Å / 360° turn
 10 nucleotide base pairs /
360° turn

6. A
T
T
A
G
C
C
G
G
C
TA
T
A
G
C
C
G
G
C
T
A
A
T
Packaging DNA
Histone proteins
Histone
octomer
B DNA Helix 2 nm

7. A
T
T
A
G
C
C
G
G
C
TA
T
A
G
C
C
G
G
C
T
A
A
T
Packaging DNA
Histone proteins
B DNA Helix
Histone
octomer
2 nm

8. A
T
T
A
G
C
C
G
G
C
TA
T
A
G
C
C
G
G
C
T
A
A
T
Packaging DNA
Histone proteins
Histone
octomer
Nucleosome
11 nm
B DNA Helix 2 nm

9. Packaging DNA
A
TA
C
G
C
G
G
C
T
A
A
T

10. Packaging DNA
A
TA
C
G
C
G
G
C
T
A
A
T

11. Packaging DNA
A
TA
C
G
C
G
G
C
T
A
A
T
Protein scaffold
11 nm“Beads on
a string”
30 nm
Tight helical
fiber
Looped
Domains200 nm

12. Packaging DNA
G
C
A
T
Protein scaffold
Metaphase
Chromosome
700 nm
11 nm
30 nm
200 nm
2 nm
Looped Domains
Nucleosomes
B DNA Helix
Tight helical fiber

13. Replication
Chromosomes, Chromatids
and Centromeres
Centromere
Chromosome
arm
Chromosome
arm
Identical
chromatid
Chromatid
Anaphase
A packaged
chromosome
Two identical
chromosomes

14. Chromosome Morphology
Chromosome
arm
Chromosome
arm
Centromere
Submetacentric Acrocentric TelocentricMetacentric
q arm
p arm
petite
Chromosomes can be distinguished on the basis
of size and the relative location of centromeres.

15. Human karyotype
(of a man with a normal 46,XY constitution)