Chapter 7 Micro
A recombinant cell
is a cell that receives DNA from an outside source and incorporates it into its own.
What is the hallmark of all horizontal gene transfers?
Transfer of DNA between organisms of the same generation
Which of the following is an example of horizontal gene transfer in bacteria?
Transduction, conjugation, and transformation
What is unique about transduction compared to normal bacteriophage infection?
Transduction transfers DNA from the chromosome of one cell to another.
How is generalized transduction different from specialized transduction?
Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.
A transducing phage
contains fragments of the host chromosome instead of the viral genome
When a transducing phage interacts with a new host cell,
the DNA from the previous host can recombine with the new host chromosome
Bacterial conjugation is often referred to as bacterial sex. Why is this term inaccurate?
Conjugation does not result in the formation of new offspring.
What must occur for bacterial conjugation to take place?
The cells must come into contact with each other.
Which statement about conjugation is false?
Conjugation is a process of bacterial reproduction.
Based on the animation, what is transferred during bacterial conjugation?
A bacterial plasmid
Competent cells are cells that
can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination.
Mice that are injected with only the R strain of Streptococcus pneumoniae
stay healthy, because their immune systems can kill this strain easily.
What characteristic of the S strain allows it to evade the immune system of the mice?
The cells have a capsule
What most likely explains the recovery of live S strain cells from a mouse injected with heat-killed S strain mixed with live R strain cells?
The R strain picked up the S strain DNA, enabling it to produce a capsule
Which finding is most surprising from Griffith’s experiments?
S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.
What kind of gene transfer between bacterial cells in the same generation utilizes the help of a virus?
What was the scientific result of Frederick Griffith's experiments with Streptococcus pneumoniae?
He showed that the DNA from strain S cells could transform strain R cells
The Ames test demonstrates that a chemical is
mutagenic in Salmonella.
A mutation that causes production of a defective pilus in a bacterium will prevent __________.