BIOL 1407: Lab #3-8
A bacteriophage is a
a virus that infects a bacterium
The bacterial flagellum moves
by rotation that is powered by the proton motive force.
Above 212 degrees F most bacteria are
destroyed
How is the movement of bacterial cells via flagella different from the movement of eukaryotic cells via flagella?
- Bacteria flagella: proton motive force - eukaryotic flagella: ATP hydrolysis
Bacterial conjugation
- direct contact btwn donor and recipient cells - shortening of the pilus - enzymatic cleavage of one strand at the origin of transfer - recipient cell becomes a donor cell after conjugation
If one donor cell is mixed with 20 recipient cells, eventually ________ cells will become donors.
20
Why do the flagella of gram-negative bacteria have a basal body with four rings, while the flagella of gram-positive bacteria have a basal body with only two rings?
Gram-negative bacteria have two cell-membranes and gram-positive bacteria have a single cell membrane
How is DNA replication during conjugation different from DNA replication preceding binary fission?
In conjugation, DNA replication involves only plasmid DNA, while replication proceeding binary fission involves chromosomal DNA
What is the biggest benefit of transformation to the bacterial cell?
The bacteria might acquire genes that make it better able to survive in its environment
Why do recipient cells become donor cells after conjugation has occurred?
They have received genes that have allowed them to produce a sex pilus
during bacterial conjugation, plasma replication occurs in
both the donor and recipient
The Gram Stain of a bacterial cell is based on the chemical properties of its
cell wall
the proper sequence of reagents in the Gram Stain procedure is
crystal violet, iodine, ethanol, safranin
With ideal environmental factors, the reproduction rate of bacteria is
extremely rapid
Many antibiotics work by preventing the proper synthesis of the peptidoglycan cell wall. These antibiotics are most likely to be effective against what types of bacteria?
gram positive bacteria
When a bacteriophage carrying bacterial DNA infects a new bacterium
it transfers bacterial DNA from the donor bacterium to the recipient bacterium
DNA transformation involves the transfer of DNA via
naked DNA in a solution
When DNA from an ampicillin resistant organism is brought into an ampicillin sensitive organism by transformation and the product is grown on agar containing ampicillin
only the transformed cells will grow
Why is most DNA acquired by transduction from the same species of bacteria?
phages are usually extremely host specific and can only infect a single bacterial species
What initiates the gliding motility in bacteria
specialized cell surface proteins and slimy polysaccharides
At freezing temperatures, most bacteria
stop growing, but are not dead.
The main environmental factors that affect mircroorganism growth include chemical inhibitors, oxygen, pH, nutrients, moisture, and
temperature
If DNA receptors on the cell surface of a bacterial cell were mutated and nonfunctional, how would that effect the bacterial cell?
the cell would be incapable of accepting naked DNA from the environment
When a recipient bacterial cell receives bacterial DNA via transduction
the new DNA is replicated every time the recipient multiplies