Microbiology Exam 3 Question Pool From Assignment 3

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What enzyme copies DNA to make a molecule of RNA?

RNA polymerase

In the figure, if base 4 is adenine, what is base 11' (remember the complimentary configuration of bases in DNA)?

adenine

If base 4 is adenine, what is base 4’?

thymine

What is not a product of transcription?

a new strand of DNA

What is a product of transcription?

tRNA, rRNA, and mRNA

What is DNA constructed of?

two strands of nucleotides running in an antiparallel configuration

A gene is defined as…

a sequence of nucleotides in DNA that codes for a functional product

When UV light strikes DNA, it can cause a specific type of damage. How is this damage best described?

Thymine bases on one strand of DNA, next to each other, are covalently linked together to form a thymine dimer

What is the first/initial effect of ionizing radiation on a cell?

highly reactive ions form

Genetic change in bacteria can be brought about by…

conjugation, mutation, transformation, and transduction

Transformation is the transfer of DNA from a donor to a recipient cell…

as a naked DNA in solution

Biotechnology involves the…

use of microorganisms to make desired products, the use of animal cells to make vaccines, and the development of disease-resistant crop plants

What is an advantage of using E. coli to make a human gene product?

its genes are well known

Restriction enzymes function as…

bacterial enzymes that destroy phage DNA

An agent used to reduce the number of bacteria on a toilet would mosst accurately be called a…

disinfectant

True or False: Most chemical agents can achieve sterility.

false

The most resistant of the bacterial endospores can withstand boiling for up to how long?

20 hours

If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar?

a pressure cooker 121°C for 15 minutes

The preservation of beef jerky from microbial growth relies on which method of microbial control?

dessication

True or False: A microwave is a method of preserving food.

False

What could be used to sterilize plastic petri plates in a plastic wrapper?

gamma radiation

What treatment is the most effective for controlling microbial growth?

140°C for 4 seconds

Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes?

freezing

Which of the following is a limitation of the autoclave?

It cannot be used with heat-labile materials

What method of microbial control does not achieve sterilization?

pasteurization

What is the best method to sterilize heat-labile solutions?

membrane filtration

Ethylene oxide…

is a sterilizing agent

What results in lethal damage to nucleic acids?

heat, radiation, and some chemicals

What concentration of ethanol is the most effective bactericide?

70%

More than half of our antibiotics are…

produced by bacteria

Most of the available antimicrobial agents are effective against…

bacteria

In the presence of penicillin, a cell dies because…

it undergoes lysis

What does not affect eukaryotic cells?

semisynthetic penicillins

What organism would most likely be sensitive to natural penicillin?

streptococcus pyogenes

A drug that inhibits mitosis, such as griseofulvin, would be more effective against…

fungi

When does drug resistance occur?

when antibiotics are used indiscriminately

True or False: Drug resistance is only found in gram-negative bacteria.

false

One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in

increased susceptibility to disease

The major significance of Robert Koch’s work is that…

microorganisms cause disease