Medical Microbiology Test 3

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Which of the following types of organisms uses hydrogen sulfide for reducing power?

purple sulfur bacteria

In which organism would you likely find a chlorosome?

green sulfur bacteria

Which of the following is a bacterium that performs oxygenic photosynthesis?

cyanobacteria

What is the key difference between photoheterotrophs and photoautotrophs?

Photoheterotrophs use organic compounds as their carbon source; photoautotrophs use carbon dioxide as their carbon source.

Which of the following is a trait unique to photosynthetic eukaryotes?

The presence of chloroplasts.

Which of the following would best inhibit the growth of a hyperthermophilic archaeon?

extremely low pH

Pyrodictium is one example of an archaeon. It lives in deep sea vents where the temperatures can be over 300°C! Which of the following best describes this archaeon?

hyperthermophile

Which of the following types of archaea is most likely to grow best at human body temperature (37°C)?

methanogens

T or F: When an endospore germinates, it gives rise to two daughter cells called vegetative cells.

False

What bacterial structure is responsible for separating the daughter DNA molecules after replication?

cytoplasmic membrane

Pleomorphic bacteria

vary in size and shape

A flexible, spiral-shaped bacterium is called a

spirochete

The anaerobic Clostridium species are troublesome pathogens largely due to their capacity for

endospore production

T or F: Cocci can be spherical as well as kidney-shaped.

True

Endospores

can be produced when nutrients are scarce

T or F: Halophiles grow equally well in the presence or absence of high salt concentrations.

False

Microbes growing in boiling hot mineral springs are generally

hyperthermophiles

T or F: The majority of archaea are extremophiles.

False

Which of the following types of microbes might be found in the Dead Sea?

halophiles

The archaea known as halophiles

are members of the Euryarchaeota and require salt concentrations above 9%.

T or F: Some strains of Staphylococcus aureus can invade the body and cause diseases such as pneumonia and bacteremia.

True

Members of which of the following genera are the most common sexually transmitted bacteria in the United States?

chlamydia

T or F: Most of the methane produced by methanogens is oxidized by other types of bacteria before it affects the Earth's climate.

True

T or F: Cyanobacteria contain chlorophyll a and carry out anoxygenic photosynthesis.

False

The genus Helicobacter is responsible for

gastric ulcers

One species of the genus Streptococcus is the leading cause of

"flesh eating" bacterial infections

Bacteria that require hydrogen sulfide are generally members of the

green phototrophic bacteria

Classification of bacteria into different phyla is based on comparisons involving which of the following?

both DNA and protein sequences

Bergey's Manual contains

classification schemes for prokaryotes.

Which of the following bacterial genera includes species that protect areas of the body such as the intestinal tract and the vagina from invasion by pathogens?

lactobacillus

Which of the following bacterial genera produce(s) endospores?

both bacillus and clostridium

Mycoplasmas are pleomorphic because

they have no cell walls.

Which of the following diseases is NOT associated with clostridia?

DIPHTHERIA botulism gangrene diarrhea tetanus

Which of the following bacterial genera is useful for sewage treatment?

zoogloea

Which of the following bacterial genera is used for the degradation of environmental pollutants?

nocardia

Pseudomonas species are occasional causes of

urinary tract infections.

How do naked viruses differ from enveloped viruses in their attachment/penetration phase?

Their nucleic acids are injected into the cell.

Which virus employs the use of an RNA-dependent RNA polymerase?

+RNA viruses

Which of the following viruses is transcribed from RNA to DNA to RNA during the replication cycle?

retroviruses

Which type of virus would produce viral glycoproteins to be expressed on the host cell membrane?

enveloped viruses

Which of the following can be used directly as messenger RNA?

+RNA

T or F: Which of the following can be used directly as messenger RNA?

True

T or F: Protozoa are susceptible to viral attack.

True

The outermost layer of a virion fulfills which of the following functions of the virus?

protection and recognition

Which of the following would NOT be found as a component of a bacteriophage?

tail fibers, dna, ENVELOPE, icosahedral capsid, base plate

Cytoplasm is a characteristic of

cells only

Double-stranded RNA genomes can be found in

only viruses

Host specificity of a virus is due to

interactions between viral and cellular surface molecules.

Which of the following statements comparing virus classification and taxonomy of organisms is true?

Genus and specific epithet are used in both classification systems.

Put the following stages of a lytic replication cycle in order, from earliest to latest stages:
I. Synthesis
II. Assembly
III. Attachment
IV. Release
V. Entry

III, V, I, II, IV

T or F:Transcription of RNA from RNA does not occur in uninfected cells.

True

T or F: Bacteriophage release is a gradual process in which small numbers are released at a time.

False

T or F: Bacteriophages are cheaper and easier to culture than animal viruses.

True

____ is a mechanism of release for enveloped viruses.

Budding

Why is lysogeny advantageous to a bacteriophage?

the genetic material of the bacteriophage can be passed on to future generations of cells.

Which of the following agents is capable of inducing conversion of a prophage back to a lytic phage?

UV light and X rays

During ___viruses remain dormant in a cell.

latency

T or F: Many diseases of plants are caused by infectious RNA molecules lacking capsids.

True

How are prions different from all other known infectious agents?

They lack nucleic acid.

Viroids infect

plants.

Plaque assays are used for

estimating the number of phages in a culture.

T or F: Virus vaccines are always cultured in embryonated chicken eggs.

False

Virus infection results in cancer in the process of

oncogenesis

Which of the following events occurs in the lytic cycle of bacteriophage T4 infection but not in the lysogenic cycle?

digestion of host DNA

Which of the following types of animal virus requires RNA-dependent RNA transcriptase to be replicated?

-ssRNA viruses

T or F: Assembly of new viruses is a process that usually requires the direction of a variety of viral and cellular enzymes.

False

Tumors invade other organs and tissues in a process called

metastasis

Which of the following is associated with the attachment of a bacteriophage to a bacterial cell?

random collisions, chemical attractions, and receptor specificity

he enzyme lysozyme is critical for which of the stages of a bacteriophage T4 infection cycle?

entry and release

T or F: Viruses cause most human cancers.

False

Spread of pathogens from one host to another by fomites is an example of ________ contact transmission.

indirect

Acne is an example of a

noncommunicable disease.

T or F: A common cold is an example of a chronic disease.

False

Diseases that are induced by modern medical procedures are referred to as

iatrogenic infections.

A nosocomial disease is a disease acquired

in a health care facility.

The study of when and where diseases occur is known as __________ epidemiology.

descriptive

The incidence of tuberculosis in the year 2000 in the United States was 12.43/100,000 cases. This means

there were 12.43 new cases of tuberculosis for every 100,000 people in the United States in the year 2000.

In early spring 2009, the CDC reported several dozen cases of novel H1N1 influenza ("swine flu") in the United States. By the summer, the number of confirmed cases was reported as over 40,000. The pattern of novel H1N1 cases in the United States represents a(n) ________ disease.

epidemic

Which of the following is NOT considered a type of vehicle transmission of a pathogen?

VIA ANIMALS, via body fluid, via air, via food, via drinking water

Fomites are

inanimate objects involved in the indirect contact transmission of pathogens.

In the wake of the cyclone that hit Myanmar (Southeast Asia) in 2008, there were widespread reports of typhoid fever. Which of the following was the most likely mode of transmission?

contaminated water

Aerosols may be involved in ________ transmission of pathogens.

droplet

T or F: A syndrome is a group of symptoms and signs that collectively characterize a particular disease.

True

T or F: Koch's postulates can be applied to every infectious disease to identify its causative pathogen.

False

Which of the following is a sign of disease?

fever

Which of the following is the correct sequence of a disease process?

incubation, prodromal period, illness, decline, convalescence

Which of the following stages of an infectious disease is the most severe?

the illness period

The ________ route is not a portal route of entry of a pathogen per se, but rather a way of circumventing the usual portals.

parenteral

T or F:Infection from a mosquito bite is an example of the parenteral route of transmission.

True

Chagas' disease is transmitted by a bug with mouthparts that penetrate blood vessels. Which type of exposure does this represent?

parenteral route

Which of the following is NOT an example of a zoonosis?

TYPHOID FEVER, rabies, salmonellosis, typhus, anthrax

A reservoir is

a source of microbial contamination.

The condition called parasitism is characterized as

a relationship between two organisms where one member harms the other.

T or F: In commensalism, one member of the relationship harms the other.

False

Mutualism is a relationship

that sometimes provides benefits for both members such that one or both parties cannot live without the other.

A pathogen is best described as

any microorganism that causes disease.

Opportunistic microorganisms are

microorganisms that may cause a disease under certain circumstances.

T or F: Normal microbiota may cause disease if they are introduced into an unusual site in the body.

True

According to the animation, surgical infections account for what percentage of nosocomial infections?

20%

What type of nosocomial infection is likely to arise from intravenous catheterizations?

Bacteremia

How might a patient who is not being treated with an antibiotic still be exposed to an antibiotic?

Antibiotics can be used in aerosols, thereby entering the environment.

Why are invasive procedures likely to increase the risk of nosocomial infections?

These procedures allow microbes from the skin to enter the bloodstream of the patient.

How can health care workers reduce the occurrence of nosocomial infections?

Practice more stringent aseptic techniques

Expected prevalence of a disease is

the expected occurrence of a disease based on past observations.

In the sixth segment of the animation, why is the disease epidemic in North America?

The disease occurs at a higher rate than what would normally be expected in this region.

In the last segment of the animation, how many regions of the world experience the pandemic during April of year four?

Five

In the last segment of the animation, when does the first epidemic occur?

January of year 3

If a disease occurs at a fairly stable rate, it is said to be

endemic.

T or F: An antiphagocytic factor is one that permits pathogens to avoid attack by macrophages.

True

Which of the following is NOT associated with bacteria in the genus Streptomyces?

the "musty" smell of soil, antibiotic production,PROTECTION OF PLANTS AGAINST CATERPILLARS, microbial antagonism, nutrient recycling in soil

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