Microbiology Exam III

The initial/first effect of ionizing radiation on a cell is that it causes

the formation of highly reactive ions

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

as naked DNA in a 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

Which of the following 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 most accurately be called a(n)

disinfectant

Which of the following pairs of terms is mismatched?

bacteriostatic – kills vegetative bacterial cells

Which of the following regarding antimicrobial control agents is FALSE?

most chemical agents can achieve sterility

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

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?

pressure cooker at 121°C for 15 minutes

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

desiccation

Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?

gamma radiation

Which of the following treatments 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

Which of the following does NOT achieve sterilization?

pasteurization

Which of the following is the best method to sterilize heat-labile solutions?

membrane filtration

Ethylene oxide is a

sterilizing agent

Which of the following results in lethal damage to nucleic acids?

heat, radiation, and some chemicals

Which of the following is mismatched?

Florey and Chain – identification of Penicillium as the producer of penicillin

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

Which of the following does NOT affect eukaryotic cells?

semisynthetic penicillins

Which of the following organisms would MOST likely be sensitive to natural penicillin?

Streptococcus pyogenes

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

fungi

Drug resistance occurs

when antibiotics are used indiscriminately

Which of the following statements about drug resistance is FALSE?

it is found only in gram-negative bacteria

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

The enzyme that is responsible for synthesizing RNA is

Transcriptase

DNA DIRECTLY participates in which of the following?

replication and transcription

Genetics and metabolism are tied together by the fact that

the genes code for enzymes that catalyze reactions that result in characteristics

A silent mutation is

always a change in base sequence and sometimes a change in amino acid sequence

The codon, UGA, would function as a stop codon on

mRNA

Which would be a product of translation?

a protein (polypeptide)

Which require(s) living donor and recipient cells?

conjugation only

Erectile dysfunction can be caused by

cigarette smoke

The following use(s) sex pheromones

gram positive conjugation

Which of the following is due to a mistake in packaging of DNA?

transduction

Chemicals in cigarette smoke that selectively cause cells with a mutation to replicate more than cells without a mutation are called

promoters

Restriction enzymes are important because they

generate overlapping sticky ends on DNA

A method of one-way gene transfer that requires cell-to-cell contact is

conjugation

Which are not Methods of Sterilization?

pasteurization and lyophilization

Endospores have resistance to some levels of ionizing radiation because they are

desiccated

If you were asked to sterilize a heat-sensitive item (and not cause damage to the item), which of the following would be most suitable?

ethylene oxide (carboxide)

Membrane filtration

does not necessarily remove viruses

Major targets for disinfectant action include

cell proteins and cell membranes

The most practical and efficient method of physical control is

heat

Which term refers to a chemical that is used at safe levels in accordance with public health requirements?

sanitizer

The chemical that is the active ingredient in Lysol is

cresol

The difference between an antiseptic and a disinfectant is

antiseptics are typically used on the skin

Criteria for usefulness of an antimicrobial agent does NOT include

destruction of a normal flora

A chemical that is not used much anymore because it is carcinogenic is

formaldehyde

The most famous antibiotic, the first one discovered, one that inhibits bacterial cell wall synthesis, is

penicillin

An example of a chemically-synthesized chemotherapeutic agent is

sulfonamide

An antibiotic (by definition) is

a chemical agent that is the product of some organism’s metabolism

For a non-growing (stationary-phase) bacterial culture, which should be most effective as an antimicrobial agent?

polymyxin B

What is the drug of choice to treat anthrax

cipro

Measures to minimize drug resistance include

discriminate use, drug dose high and combination of drugs

Conceivably, the most common mechanism of microbial resistance is

alteration of target molecule

Many cases of the flu on a college campus would be referred to as an

epidemic

Which of the following is a factor in the development of disease?

number of pathogens, vectors, ability to flourish outside of the body

Cholera, a very serious disease in many areas of the world, is normally transmitted via the

gastrointestinal tract

An example of a disease normally transmitted via that blood is

hepatitis

A disease organism that is present in high numbers in a specific geographical location is referred to as an

endemic

Which organism requires fimbriae to stick to the lining of the genitourinary tract?

E. coli

What has been shown to remain active and infectious for hour on a toilet seat?

herpes virus

Which of the following diseases requires a tick vector for transmission?

rocky mountain spotted fever

A key discovery that contributed to the development of genetic engineering was

restriction enzymes

Genetic engineering very often uses what to move hybrid plasmids into cells?

transformation

Cigarette smoke contains ______ mutagenic agents while ultraviolet
radiation is a ______ mutagenic agent.

chemical, physical

Restriction enzymes are important because they

generate overlapping sticky ends on DNA

Genetic modification procedures can be used to

clone genes for pest resistance, produce human growth hormone, and clone genes for toxic waste clean up

An autoclave utilizes

moist heat under pressure

Membrane filtration

is a method of sterilization

Lyophilization

is a method of preservation

A common method for sterilizing laboratory glassware is

dry heat (oven)

Adding salt to ham or sugar to canned fruit is an example of what type of control?

osmotic pressure

The major effect of using ionizing radiation on living organisms is

the production of hydroxyl radicals from the water

Which is not a method of sterilization?

ultraviolet radiation

Factors that normally affect disinfection include

time, temperature, concentration, surrounding medium

One of the best disinfectants to use for a biological spill is

bleach

If you were asked to a sterilize a heat-sensitive item (and not cause damage to the item), which of the following would be most suitable?

ethylene oxide (carboxide)

Which of the following is FALSE?

Isopropyl alcohol is used the sterilize the skin

The difference between an antiseptic and a disinfectant is

antiseptics are normally used on the skin

A chemical that would be used to inhibit, but not necessarily kill fungi, would be called

fungistatic

An example of a mild antiseptic is

hydrogen peroxide

The primary targets in a cell for disinfectant action are

cell membrane and cellular proteins

Antimicrobial agents

hopefully do not result in the disease-causing organism becoming resistant

Ciprofloxacin, the drug of choice for anthrax, inhibits the synthesis of

DNA

The presence of non-multiplying bacteria in the blood is

bacteremia

Tuberculosis and leprosy are usually examples of

chronic infection

Examples of a pandemic include

AIDS and swine flu

Invasive mechanisms of bacteria include

capsules, enzymes, fimbriae and exotoxins

Swine flu virus can enter and leave the body by means of

respiratory route

So far the swine flu has been a relatively mild disease in those without health issues. This is due to its

virulence

The term that is used for a hospital-acquired infection is

nosocomial infection

When disease symptoms develop rapidly, typically with a high fever, the person has

an acute infection

E. coli and Neisseria gonorrhoeae (the organism that causes gonorrhea) use what to stick to the lining of the genitourinary tract?

Fimbriae