Microbial Genetics
A. The concept of the gene
B. Molecular Structure
DNA - macromolecule composed of a chain
of nucleotides.
Deoxyribose - each nucleotide is composed
of a pentose sugar.
Erwin Chargaff
Charfgaff’s Rule
There should be the same number of
adenine and thymine and the same guanine
and cytosine.
C. Organization of DNA in prokaryotic and
eukaryotic chromosomes
Prokaryotic Chromosomes
- prokaryotic nucleoids are always known to
segregate continuously, as they replicate, and
without additional condensation.
Nitrogenous bases:
Purines (A: adenine, G: guanine)
- most bacterial genomes are negatively
- double ring structure.
supercoiled during normal growth. Once the
Pyrimidines (C: cytosine, T: thymine)
genome has been condensed, DNA
- single ring structure.
topoisomerase I, DNA gyrase, and other
proteins help maintain the supercoils.
A. The concept of the gene
B. Molecular Structure
DNA - macromolecule composed of a chain
of nucleotides.
Deoxyribose - each nucleotide is composed
of a pentose sugar.
Erwin Chargaff
Charfgaff’s Rule
There should be the same number of
adenine and thymine and the same guanine
and cytosine.
C. Organization of DNA in prokaryotic and
eukaryotic chromosomes
Prokaryotic Chromosomes
- prokaryotic nucleoids are always known to
segregate continuously, as they replicate, and
without additional condensation.
Nitrogenous bases:
Purines (A: adenine, G: guanine)
- most bacterial genomes are negatively
- double ring structure.
supercoiled during normal growth. Once the
Pyrimidines (C: cytosine, T: thymine)
genome has been condensed, DNA
- single ring structure.
topoisomerase I, DNA gyrase, and other
proteins help maintain the supercoils.
