Topic 2 Molecular Genetics: Molecular Genetics of Bacteria Flashcards
1
Q
- Bacteria are prokaryotes with no nucleus or organelles, consist of a single, circular, double stranded DNA molecule (that is tightly condensed and called a nucleoid), and have no histones or other associated proteins. Let’s briefly cover some important terms:
A
Note
2
Q
- Bacteria reproduce via this method in which the chromosome replicates, the cell divides into two cells, and each cell now holds the exact same copy of the original chromosome
A
- Binary Fission
3
Q
- Because bacteria lack a nucleus, they also lack microtubules, spindles, and centrioles
A
Note
4
Q
- Short, circular DNA outside of chromosomes that carry genes that are beneficial, but not essential for survival
a. Episomes - plasmids that can incorporate into bacterial chromosomes
b. Plasmids are what help bacteria gain characteristics like antibiotic resistance
A
- Plasmids
5
Q
- There are three main ways bacteria can exchange information with each other or their surroundings
A
- Genetic Exchanges
6
Q
a. Conjugation
b. Transduction
c. Transformation
A
Types of Genetic Exchanges
7
Q
- Donor bacteria produces a bridge (pilus) and connects to the recipient bacteria; this allows the donor to send a chromosome or plasmid to the recipient, thus allowing recombination to occur
a. An F plasmid allows a pilus to form, and a once the recipient receives the F plasmid, it is now F+ and can donate this plasmid as well
b. Pili are also used for cell adhesion!
A
a. Conjugation
8
Q
- DNA is introduced into a genome via virus. When the virus is assembled during the lytic cycle, some bacterial DNA is incorporated in the place of viral DNA. When the virus infects another host, the bacterial DNA part that it delivers can recombine with the resident DNA.
A
b. Transduction
9
Q
- Bacteria take in DNA from surroundings and incorporate it into the genome
A
c. Transformation
