Introduction to Bacteria (2) Genetics Flashcards
How do bacteria replicate?
binary fission
What are the offspring like of bacteria?
identical progeny
How is variation created in bacteria?
spontaneous mutation
transfer of DNA (plasmids)(conjugation)
What is bacterial conjugation?
transfer of genetic material between bacterial cells
What do you term a bacteria with and without an F plasmid?
with = donor cell
without = recipient
What does the F plasmid encode?
F pilus
What is the first stage in plasmid transfer?
contact between donor and recipient
How does the donor cell attach to the recipient cell?
the pilis attaches to receptors on the surface of the recipient cell
What happens when the donor and recipient bacteria are attached?
A specific endonuclease cleaves the plasmid at a specific sequence (origin of transfer).
It is replicated via a rolling circle mechanism
What happens when F plus and F minus cells are mixed together?
all cells eventually become F plus
What is a bacteriophage?
A bacteriophage is a type of virus that infects bacteria. In fact, the word bacteriophage literally means ‘bacteria eater’, because bacteriophages destroy their host cells
Describe the structure of a bacteriophage
composed of a nucleic acid molecule that is surrounded by a protein structure.
What is the mechanism of action of a bacteriophage?
A bacteriophage attaches itself to a susceptible bacterium and infects it.
Following infection, the bacteriophage hijacks the bacterium’s cellular machinery to prevent it from producing bacterial components and instead forces the cell to produce viral components. Eventually, new bacteriophages assemble and burst out of the bacteria in a process called lysis.
What molecule is this?
bacteriophage
What is the treatment associated with bacteriophages?
Bacteriophages are being investigated as treatments for infections –known as ’phage therapy’ –particularly where antibiotics have not been effective.
Name structures A-E
What are the; dark blue, yellow and pink cells?
B. subtilis
non-sporulating cells (dark blue)
cells that have begun spore-formation by dividing asymmetrically (yellow) and small (pink) chambers.
Describe the process of sporulation
Endospore formation (sporulation) is the prime example of a complex bacterial developmental process. Sporulating bacteria undergo an intricate sequence of cell differentiation events leading to the formation of a highly resistant dormant spore that can germinate when conditions improve.
