Exam 3 True/False
Any process that destroys the non-spore forming contaminants on inanimate objects is sterilization.
F
Desiccation is a reliable form of sterilization.
F
In performing a ten-fold dilutions series from a sample containing 10,000 bacteria per milliliter, the fourth tube in the dilution series will have 10 cells per milliliter.
F
Microorganisms placed in high concentrations of salts and sugars undergo lysis.
F
Most pathogenic bacteria are thermophiles.
F
Nearly all cells, including E. coli and yeast, naturally take up DNA from their surroundings without chemical treatment.
F
Pure cultures can easily be obtained on streak plates, even if the desired bacteria are present in very low concentrations in the initial culture broth.
F
The Ti plasmid isolated from Agrobacterium can be used to insert DNA into any type of plant.
F
The pH of the medium has no effect on the activity of the disinfectant being applied.
F
The practice of breeding plants and animals for desirable traits, such as high crop yield, is called natural selection.
F
The term biotechnology refers exclusively to the use of genetically engineered organisms for the production of desired products.
F
Ultraviolet light (UV) causes irreversible breaks in DNA strands.
F
A shuttle vector is a plasmid that is used to move pieces of DNA among organisms, such as bacterial, fungal, and plant cells.
T
Agar is used as a solidifying agent in microbiological media since few bacteria can degrade it.
T
An isolated colony on a streak plate contains millions (or even billions) of identical cells all arising from one initial cell.
T
Autoclaving is the most effective method of moist heat sterilization.
T
Bacterial growth refers to an increase in the numbers of cells in a bacterial culture.
T
Bioinformatics is the use of computer technology to compare and analyze genome sequence.
T
Filtration methods, followed by growth of the bacteria trapped on the filters in growth media, are used to count bacteria present in very low concentrations, such as in lakes and streams.
T
In recombinant DNA technology, a vector is a self-replicating segment of DNA, such as a plasmid or viral genome.
T
Laboratory cultivation of obligate anaerobes requires reducing media or special growth chambers filled with inert gases.
T
Moist heat destroys organisms by denaturing proteins.
T
Nitrogen-fixing bacteria, such as cyanobacteria, can use atmospheric nitrogen (N2) for their nitrogen source.
T
One of the first commercial successes of recombinant DNA technology was the production of human insulin using genetically engineered E. coli.
T
Pseudomonas has been found growing in quaternary ammonium compounds (quats).
T
Some antimicrobial chemicals are considered to be disinfectants and antiseptics.
T
The Bt toxin derived from Bacillus thuringiensis has been introduced into some crop plants to make them resistant to insect destruction.
T
The disadvantage of genomic libraries over cDNA libraries is that genomic libraries contain gene introns.
T
The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature.
T
Turbidity is an indirect measurement of bacterial growth that can be measured using a spectrophotometer.
T
