Micro - Exam 4 - Mastering

The human parasitic infection caused by a protozoan that enters through the nose is caused by __________. Naegleria fowleri Entoamoeba histolytica Giardia intestinalis Ballantidium coli

Naegleria fowleri

Azole medications inhibit the production of ergosterols. Which infection would they be most effective against? -a tapeworm -a ringworm infection of the scalp -a bacterial infection -malaria

a ringworm infection of the scalp

Which of the following is an example of a secondary systemic mycosis? -a Staphylococcus aureus infection on the surface of the skin -cryptococcosis that develops in the lungs of a patient with HIV/AIDS -a ringworm infection of the scalp -amoebic dystentery, a gastrointestinal illness

cryptococcosis that develops in the lungs of a patient with HIV/AIDS

The ideal bioweapon would be __________. -one with low morbidity -one that is cheap to produce, even if it is difficult to disseminate -one that is easily spread in aerosol form -one that requires safety equipment to handle

one that is easily spread in aerosol form

Changes in the human microbiome have been associated with __________. arthritis obesity esophageal cancer type 1 diabetes

obesity

A major cause of helminthic infectious blindness is __________. Bancroft's filariasis onchocerciasis schistosomiasis trichinosis

onchocerciasis

Leishmania parasites live within leukocytes. Which type of cell is most likely to harbor them? plasma B cells memory B cells natural killer cells macrophages

macrophages

During the 2002-2004 emergence and epidemic of Severe Acute Respiratory Syndrome corona virus (SARS-coV) the virus was found to be highly contagious, with an observed reproductive number (R) of 3.6. For this reason many rigorous means of infection control were instituted by the countries experiencing SARS outbreaks, including__________. culling of chickens. vaccination. quarantine and isolation. application of DDT to kill mosquitoes.

quarantine and isolation

An antimicrobial compound that targets a pathway or structure that is present in a pathogen but not in the host exhibits __________. narrow spectrum activity antibiotic resistance complete toxicity selective toxicity

selective toxicity

Karen stepped on a rusty nail while walking her dog barefoot. She needs to be treated to prevent damage by which exotoxin? cholera exotoxin hemolysin tetanus exotoxin botulinum exotoxin

tetanus exotoxin

Which of these organisms has hyphae? a bread mold an amoeboid protozoan rotifers a Staphylococcus aureus bacterium

a bread mold

Mutualisms may become prolonged, intimate and obligate symbioses through the process of __________. -coevolution -endocytic colonization -horizontal gene transfer -parasitism

coevolution

Pathogenic strains of Escherichia coli usually express -colonization factor antigens (CFA). -capsules. -plaques. -slime layers.

colonization factor antigens (CFA)

Microbes that have a mutualistic relationship with their host are beneficial to their host, while __________. -parasites cause disease -symbionts benefit at the expense of the host -pathogens kill the host -commensals have little or no effect on the host

commensals have little or no effect on the host

All students that ate in the school dining hall on Monday developed stomach cramps and diarrhea. The student clinic was overwhelmed with patients. However, by Thursday the number of patients seen in the clinic was back to normal. This could have been caused by a __________. common-source epidemic vector-borne disease host-to-host epidemic infectious disease

common-source epidemic

The Plasmodium life cycle is very complex, involving two hosts. Which of the choices shows the correct sequence of events in this cycle? 1. Red blood cells are infected. 2. Mosquito bite occurs. 3. Plasmodium enters the liver. 4. Red blood cells are destroyed. 5. Plasmodium grows and develops sporozoites. 3, 5, 1, 4, 2 2, 5, 3, 1, 4, 2 2, 3, 1, 5, 4, 2 1, 5, 4, 3, 2, 1

2, 5, 3, 1, 4, 2

A disease that is transferred by direct intimate contact with a mortality rate over 90% would be an effective biological weapon. True False

False

Emerging infectious disease will likely affect only developing countries in the near future. True False

False

Antibiotic resistance is a major concern as microbes can rapidly develop resistance when antibiotics are not used appropriately. Which of the following examples best describes how this occurs? -Antibiotics are mutagenic. They cause mutations, like other mutagenic chemicals. -Exposure to too much of an antibiotic causes resistance. -Microbes respond to the presence of antibiotics by deliberately developing resistance mechanisms. -In any population of microbes, some individuals may have resistance genes. When exposed to an antibiotic, there is selection for the microbes that have these genes.

In any population of microbes, some individuals may have resistance genes. When exposed to an antibiotic, there is selection for the microbes that have these genes.

Eosin-methylene blue agar inhibits the growth of gram-positive organisms while allowing gram-negative organisms to grow. Colonies of lactose fermenters turn a blackish color while nonfermenters are colorless. How would you classify EMB? Is EMB a differential medium or a selective medium? Think about the meaning of the terms differential and selective to choose your answer. -It is neither differential nor selective. -It is a differential medium and a selective medium. -It is a selective medium only. -It is a differential medium only.

It is a differential medium and a selective medium.

Why is a special polymerase, such as Taq polymerase, used for PCR? -It is able to add DNA nucleotides without requiring an existing strand to add on to. -It works at relatively high temperatures. -It can add both DNA and RNA nucleotides. -It has exceptionally good proofreading ability.

It works at relatively high temperatures

Why is there such a difference between the flora in the duodenum and that in the ileum? -There is a large difference in the pH between these regions of the large intestine. -There is a large difference in the nutrients available in these regions of the large intestines. -There is a large difference in the nutrients available in these regions of the small intestine. -There is a large pH difference between these regions of the small intestine.

There is a large pH difference between these regions of the small intestine.

Virulence factors that enhance invasiveness of a pathogen can include __________. exotoxins collagenase coagulase all of the listed responses

all of the listed responses

An unknown bacterium was isolated from a patient with pneumonia. To determine the minimum inhibitory concentration of the chosen drug to use to treat the respiratory infection, the doctor must take into account __________. -time of incubation -pH of growth medium -all of the listed responses are correct -concentration of amino acids in the medium

all of the listed responses are correct

Malaria is caused by a protist that is transmitted by mosquitoes. During its life cycle, the protist goes through cycles of destroying erythrocytes. Which of the following medical consequences is most directly related to this cell damage? fever headache chills anemia

anemia

Organisms that colonize skin __________. -are mostly gram-positive bacteria -do not include eukaryotes -are always aerobes -are never pathogenic

are mostly gram-positive bacteria

Symbionts can be acquired by an individual host organism horizontally (from the environment) or vertically (from a parent). In humans, there is evidence that family members living in the same household have microbiomes that are more similar than those of individuals living nearby in the same town but not in the same house. However, no two humans have identical microbiota. This indicates that humans may be colonized by__________. -vertical transmission -neither vertical nor horizontal transmission -both vertical and horizontal transmission -horizontal transmission

both vertical and horizontal transmission

The emergent H5N1 strain of avian influenza can occasionally be transmitted from birds to humans with a resulting 60% mortality rate (compared with a 2.5% mortality rate for the 1918 pandemic influenza). In 2012, after a single dead chicken in a wholesale market in Hong Kong tested positive for H5N1, all 17,000 chickens in the market and surrounding area were culled. This was an attempt to__________. prevent migration. eliminate a vector. quarantine . eliminate a reservoir.

eliminate a reservoir

A disease that is constantly present in a population at low numbers is a(n) __________. endemic outbreak epidemic pandemic

endemic

Factors that enhance an organism's ability to adhere to host tissues include __________. adherence enzymes fimbriae peptidoglycan lipopolysaccharide

fimbriae

A person would be most at risk of infections if he or she __________. -is an active 30-year-old going through a divorce -is a 70-year-old alcoholic whose spouse just died -eats fast food every day of the work week and sleeps 9 hours a night -is a breast-feeding infant with a vegetarian mother who runs 5 miles a day

is a 70-year-old alcoholic whose spouse just died

Decalcification of the tooth enamel due to the production of high concentrations of organic acids in the mouth is known as -degenerative plaque. -dental plaque. -dental caries. -microbial enamel decalcification.

microbial enamel decalcification

The ability to cause disease is __________. pathogenicity colonization virulence infection

pathogenicity

H5N1 avian influenza is widely considered to be the most serious global pandemic threat today, and is the target of much worldwide surveillance. Currently, the virus is not readily passed person-to-person, but reports that the virus may have recently entered (or re-entered) the swine population are of concern because of__________. -possible reassortment of the influenza genome with swine and human strains. -possible antigenic drift. -humans typically come into more frequent contact with swine than with birds. -influenza more easily passing from pig-to-human than from human-to-human.

possible reassortment of the influenza genome with swine and human strains.

During the early 20th century, pandemics typically took months to years to span the globe, while the 2009 H1N1 swine flu spread globally within weeks and had affected most countries within 6 months. This difference in the rate of spread is mainly due to__________. -the emergence of antibiotic resistance. -the increased volume and speed of global transportation. -more human contact with wild and domestic animals worldwide. -the increased virulence of the pathogens.

the increased volume and speed of global transportation

Among the recommendations from the Centers for Disease Control and Prevention to limit the development of antibiotic resistance are __________. -to treat with broad spectrum drugs -to treat with the oldest, effective antimicrobial -to treat with the newest, effective antimicrobial -to stop taking the antimicrobial as soon as symptoms disappear

to treat with the oldest, effective antimicrobial

Bacterial fermenters themselves are a significant source of nutrition for ruminants, but not for hindgut fermenters, because __________. -in ruminants the bacteria mostly leave the rumen to be digested, while in hindgut animals the bacteria are retained in the cecum -they pass through an acidic chamber and are digested -ruminants have more nutritious species of bacteria than hindgut fermenters -the bacteria are attached to plant particles in ruminants

they pass through an acidic chamber and are digested

All AB toxins have which of the following? two subunits hemolytic activity immunogenic properties lipid A

two subunits

A higher number of methanogenic Archaea are found in the guts of mice and humans who are obese. It is thought that the methanogens help to foster obesity by__________. -using H2, thus allowing further fermentation of substrates -preventing the production of methane, thus enhancing nutrient absorption by the host -creating a more oxidative environment, thus allowing respiration to occur. -preventing further fermentation of substrates, thus allowing them to be used by the host

using H2, thus allowing further fermentation of substrates

All of the following are typical gram-positive organisms found on the skin EXCEPT __________. Propionibacterium Staphylococcus Bacteroides Corynebacterium

Bacteroides

The visceral parasites that are of great concern to people with compromised immune systems include __________. Trichomonas Cryptosporidium Cyclospora Giardia

Cryptosporidium

The incidence of HIV among hemophiliacs and transfusion recipients has remained constant since 1994. True False

False

To control a disease in a population, 100% immunization is necessary. True False

False

Amphotericin B is an antifungal medication. What might its mechanism of action be? -It prevents synthesis of peptidoglycan cell walls -It binds to ergosterol. -It binds to ribosomes. -It binds to phospholipids in fungal membranes.

It binds to ergosterol

Entamoeba histolytica, transmitted by contaminated food, grows on and in the cells lining the intestine and later within the intestinal wall. This results in dysentery. What best describes the relationship between E. histolytica and its host? It is a mutualistic relationship. It is a parasitic relationship. It is amensalism. It is a commensalism.

It is a parasitic relationship

You are examining a sample to determine whether there is a pathogen present that might explain symptoms in a patient. You find a unicellular organism that lacks mitochondria, having mitosomes instead. It has a flagellum and a nucleus. What is it? -It could be a protist or an animal cell because it has a nucleus. -It must be a bacterium because it has no mitochondria. -It must be a bacterium because it has a flagellum. -It must be a eukaryotic protist because it has a nucleus.

It must be a eukaryotic protist because it has a nucleus.

Lactose-fermenting bacteria turn eosin-methylene blue medium from colorless to black or red. What causes this change? -Lactose fermentation generates lactate, making the medium more alkaline and causing the color change. -Lactose fermentation allows pyruvate to build up. This excess of pyruvate causes the color change. -Lactose fermentation generates alcohol. The alcohol reacts with chemicals in the medium to cause the color change. -Lactose fermentation generates lactic acid. Lactic acid lowers the pH of the medium, causing the medium to change colors.

Lactose fermentation generates lactic acid. Lactic acid lowers the pH of the medium, causing the medium to change colors.

________ in saliva cleaves glycosidic linkages in peptidoglycan present in bacterial cell walls, weakening the wall and causing cell lysis. Fibrin Lysozyme Mucus Lipid A

Lysozyme

What benefit does the fungal partner get from the lichen relationship? -The alga produces lichen acids that help provide inorganic nutrients from the substrate. -The alga anchors the fungus to the substrate. -The alga facilitates water uptake. -The alga provides organic compounds for food to the fungus.

The alga provides organic compounds for food to the fungus.

A researcher wanted to determine the LD50 (lethal dose50) for a newly-isolated bacterial pathogen. Mice were inoculated with diluted cultures containing between 101 and 107 cells. After two days, all of the mice had died, EXCEPT for the uninoculated controls. Which of the following is the most likely explanation? -This pathogen is highly virulent in mice. -Mice are not good model animals for this pathogen. -The pathogen has a very high LD50 -The pathogen has become attenuated.

This pathogen is highly virulent in mice

A disease transferred by indirect contact with a high basic reproduction number and mortality would be an effective biological weapon. True False

True

Changes in food processing and distribution can increase the incidence of new and emerging diseases. True False

True

Chitin is found ONLY in fungi and insects. True False

True

Gram stain smears of urethral exudates for the detection of Neisseria gonorrhoeae are highly specific. True False

True

In 2011, the CDC reported a 28-state outbreak of Listeria monocytogenes that killed 33 people in the U.S. The victims were found to have eaten portions of whole cantaloupe melons originating from a single farm in Colorado. The FDA traced the source of bacterial contamination to a piece of recently-purchased used equipment that was used to wash the melons, as well as nearby puddles of water and a truck that hauled spoiled melons to a field to be fed to cattle. This would be an example of__________. zoonotic reservoir. common-source transmission. person-to-person transmission. water-borne transmission.

common-source transmission

When the human papillomavirus (HPV) vaccine was first introduced to help prevent cervical cancer and anal warts and cancers, it was only recommended for 11- or 12-year old girls. However, the CDC later expanded their HPV vaccination recommendations to include 11- and 12-year old boys. By including males, the public health officials hoped to do all but one of the following: -increase herd immunity to HPV -protect men from anal warts and cancer -decrease the incidence of cervical cancer -decrease the basic reproductive number (R0) of HPV

decrease the basic reproductive number (R0) of HPV

Superficial mycoses are caused by a group of fungal pathogens called __________. dimorphic dermatophytes dermatologic dematiaceous

dermatophytes

During the Jurassic Period, several different mammalian lineages independently evolved an herbivorous lifestyle for obtaining energy. This has resulted in -different digestive patterns in herbivorous animals, some that depend on gut microbiota to digest plant material and some that do not. -horizontal gene transfer of genes for glycoside hydrolases and polysaccharide lyases from bacteria to mammals. -different digestive patterns in herbivorous animals that all depend on gut microbiota to digest plant material. -the evolution of foregut fermentation, as seen in ruminants, as the only digestive pattern that depends on fermentative gut microbiota.

different digestive patterns in herbivorous animals that all depend on gut microbiota to digest plant material.

Fungi that can grow in a yeast or a mold form depending on the conditions are termed __________. pleomorphic morphic dimorphic amphimorphic

dimorphic

The type of mycorrhizae found associated with forest trees like pines would be __________. arbuscular mycorrhizae none; not all plants form mycorrhizal associations endomycorrhizae ectomycorrhizae

ectomycorrhizae

For many years the CDC focused its seasonal influenza vaccination efforts on those groups in the population who suffered the highest influenza mortality rates, including the elderly aged 65 years and older. However, starting in 2008 the CDC shifted their focus to school-aged children and began recommending the vaccine for everyone aged at least 6 months. Research had shown no evidence for any protective effect of the vaccine in the elderly. By changing the recommendations for who should be vaccinated, the CDC planned to better protect the elderly by means of__________. direct contact. vaccination. acquired immunity. herd immunity.

herd immunity

Free flu shots were given at school, but 3 of the 30 students were absent that day. The next week Bob starting showing signs of the flu and was coughing and sneezing in class. None of the other students contracted the virus, even those that missed the shot. This can be explained by __________. immunizations resistance herd immunity vaccinations

herd immunity

Appropriate action to control infectious disease where humans are the reservoir would include __________. immunization eliminate breeding grounds control of the vehicle control of the vector

immunization

Incidence of healthcare associated infections are __________. -increased because hospital personnel are well trained and always follow proper hand washing protocols -increased because there are few pathogen reservoirs -increased because patients are fully immunocompetent -increased because patients are exposed to pathogens that have increased drug resistance

increased because patients are exposed to pathogens that have increased drug resistance

The most common method of contracting a systemic mycosis is through __________. ingestion sexual contact person-to-person contact inhalation

inhalation

A farmer finds that his soybean plants do not look healthy. They appear stunted and the leaves are a yellowish color, indicating possible lack of nitrogen. To have a more successful crop next year, he should consider__________. -fertilizing with ammonia fertilizer -increasing irrigation of his fields. -fertilizing his fields with iron. -inoculating his fields with the appropriate cross-inoculation group of rhizobia

inoculating his fields with the appropriate cross-inoculation group of rhizobia

The incidence of disease in a population is termed the __________. outbreak prevalence morbidity mortality

morbidity

In the first reported epidemiological study in 1854, John Snow attempted to discover the source of a London cholera epidemic by going house-to-house and recording deaths. When he mapped the results, he was able to identify the Broad Street water pump as the likely source of contaminated water. The data collected in this study was__________. mortality. incidence. prevalence. morbidity.

mortality

What is the term used for the filamentous body found in many fungal species? gametophyte mycelium protonema dikaryote

mycelium

The evolution of plants that grow on dry land is thought to have depended in part on their development of symbiotic associations with which group of microorganisms? -lichens -Agrobacterium -rhizobia -mycorrhizae

mycorrhizae

In the search for new antimicrobial drugs, to minimize resistance developing scientists should focus on __________. -new targets of action found only in eukaryotes -combinations of current antimicrobial compounds -modifications of current antimicrobial compounds -new targets of action found only in bacteria

new targets of action found only in bacteria

Some lichen symbionts can survive independently on bare rocks in the absence of any external source of organic matter due to the ability of the phototrophic partner to fix CO2 from the air, and __________. -nitrogen fixation by the cyanobacterial partner -acquisition of water by the algal partner -chemolithotrophy by the bacterial partner. -production of acids by bacterial fermenters to release minerals from the rock.

nitrogen fixation by the cyanobacterial partner

It is difficult to attain good selective toxicity with antiviral drugs because of the fact that __________. -viruses require host cells to replicate themselves -viruses can hide in an envelope from the host cell -viruses are not cells -viruses are not living organisms

viruses require host cells to replicate themselves

What is the primary source of energy for ruminant animals? -methane -volatile fatty acids -cellulose -glucose

volatile fatty acids