Micro Lecture Final Homeworks

What structure can the viral genome take?

*ss-DNA *ds-DNA *ds-RNA

Clostridium tetani is an obligate anaerobe that can cause tetanus. When it enters the human body, it can produce tetanus toxin. Considering that C. tetani is an obligate anaerobe, which of the following explains how it can survive and cause disease in the human body?

Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow.

Which of the following pairs is mismatched?

Ergot - gangrene Salmonella endotoxin - coagulates blood* Vibrio enterotoxin - massive fluid loss Shiga toxin - tissue destruction Aflatoxin - liver cancer

The most common cause of traveler's diarrhea is probably

Escherichia coli.

There are several different virus-specific treatments and vaccines available to treat or prevent hantavirus infections. (T/F)

False

Recurring vesicles are symptoms of

Genital herpes.

Which infection is NOT caused by Staphylococcus aureus?

Glomerulonephritis

Infection by which of the following results in the formation of Ghon complexes?

Mycobacterium tuberculosis

What is apoptosis?

The process of programmed cell death.

Most gastrointestinal infections are treated with

Water and electrolytes.

As a consequence of infection by a temperate bacteriophage such as lambda, the host cell

may lyse or may continue to divide and replicate both itself and the prophage.

Controlling most rickettsial diseases involves managing

the vector.

Retroviruses are medically important viruses because

they include some viruses that cause cancer and HIV.

The causative agent of Hansen's disease is

Mycobacterium leprae.

Which of the following pathogens is spread by infected fleas?

Rickettsia typhi

The DTaP vaccine contains

diphtheria toxoid.

The common methods to control the spread of West Nile virus include __________.

using insect repellents

Epidemiology is defined as the study of

where and when a disease occurs, and how it is transmitted.

Animal diseases transmissible to humans are known as

zoonoses.

Since the majority of human papillomavirus (HPV) infections are asymptomatic, screening for this infection is __________.

necessary because chronic infection can lead to cervical cancer

Which disease test will show a false positive when immunized with the BCG attenuated virus?

tuberculosis

The HIV genome consists of

two identical ssRNA molecules.

Example of a vector?

A fly carrying disease from fecal matter to food

Which of the following would be considered a fomite?

A toy

Which of the following is evidence that the arthritis afflicting children in Lyme, Connecticut, was transmitted by a vector?

Accompanied by a rash Not contagious* Treatable with penicillin Affected mostly children

What is the primary benefit of vaccination?

An immune response will occur quicker upon future exposure to the pathogen.

Why are antibiotics often ineffective in treating food poisoning (food intoxication)?

Antibiotics target bacteria; they do not damage toxins.

On October 5, a pet store sold a kitten that subsequently died. On October 22, rabies was diagnosed in the kitten. Between September 19 and October 23, the pet store had sold 34 kittens. Approximately 1000 people responded to health care providers following local media alerts. These people were given

Antirabies immunoglobulin and rabies vaccination.

The majority of cases of human plague in the United States occur in the northeastern states. (T/F)

False

The organisms that cause pneumococcal pneumonia are rarely found as a part of the normal flora of healthy adults. (T/F)

False

The toxic lipopolysaccharides produced by most gram-negative bacteria are called exotoxins. (T/F)

False

Bacterial intoxications differ from bacterial infections of the digestive system in that intoxications

Have shorter incubation times.

Which of the following is NOT transmitted by the respiratory route?

Helicobacter pylori

Which of the following is the causal agent of gastric ulcers?

Helicobacter pylori

What are leukocidins?

Molecules that are capable of destroying phagocytes

Tuberculoid Hansen's disease is caused by the pathogen

Mycobacterium leprae.

A meningitis with a purple spotted rash that does NOT blanch (whiten) when pressed is characteristic of an infection by

Neisseria meningitidis.

Which of the following statements about rabies is false?

The RIG vaccine is a pre-exposure vaccine.

Mass-processed ground meat is a particularly common source of infection with EHEC. (T/F)

True

Which of the following microorganisms actually grows inside the macrophage?

Tuberculosis bacterium

In bubonic plague, buboes are swellings formed in the lymph nodes and filled with

Yersinia pestis.

What does a vaccine contain?

Weakened or killed pathogen or parts of a pathogen

Which of the following was an emerging mosquito-borne disease in the early 2000s but has now decreased in frequency?

West Nile fever

Vibrio cholerae is a human pathogen that causes cholera. It has an unusual shape distinctive of its genus. Considering that it does not have one of the most common bacterial shapes, what is the shape of this species?

a curved rod

Restriction is

a general host mechanism to prevent the invasion of foreign nucleic acid.

Which insect functions in the host-to-host transmission of epidemic typhus?

body louse

Which of the following are viable methods of release of newly assembled viral particles?

budding or lysis of host cell

A person is MOST likely to contract diseases such as Rocky Mountain spotted fever if he or she visits/participates in

camping and hiking in the backcountry.

The degree of susceptibility a food has to microbial activity is determined by its

chemical characteristics, physical characteristics, and water content.

Cellular receptors may be composed of

combinations of proteins, carbohydrates, and/or lipids.

All viral particles

are metabollicaly inert

Which molecule triggers apoptosis?

Granzyme

Which of the following organisms is likely to be transmitted via contaminated shrimp?

Vibrio

Which of the following pairs is mismatched?

-Acute bacterial endocarditis - Staphylococcus aureus -Lyme disease- Borrelia burgdorferii -Subacute bacterial endocarditis - Enterococcus -Plague - Yersinia pestis -Glomerulonephritis - Staphylococcus aureus*

How are typhoid fever and salmonellosis different?

-Typhoid fever is seen in humans only. Salmonellosis is seen in many animals. -Organisms that cause typhoid fever are found in the gallbladder. No organisms in the gallbladder in salmonellosis.

How can capsules enable bacteria to evade the immune system?

Capsules block the complement biding sites on the surface of the pathogen.

In what year did Stanley Prusiner discover prions?

1982

Which type of vaccine could possibly cause a person to develop the disease?

Attenuated live vaccine

Which of the following explains why treatment of symptomatic tetanus requires an antitoxin and an antibiotic?

Because C. tetani bacteria excrete tetanus toxin, it is important to neutralize the toxin while also killing the bacteria that are producing more.

What is the function of boosters?

Boosters are injections that are given periodically to maintain immunity.

A patient has a paroxysmal cough, mucus accumulationand is gasping for air. What is the etiology of the symptoms?

Bordetella

Microscopic examination of a patient's fecal culture shows spiral bacteria. The bacteria probably belong to the genus

Campylobacter.

Which of the pairs below are matched correctly for these clostridial pathogens involved in food poisoning?

C. perfringens: produces enterotoxin* C. botulinum: produces endotoxin C. botulinum: must grow in the body to produce toxin C. perfringens: requires only a small number of cells to produce toxin

"Rice water stools" are characteristic of

Cholera.

Which of the following prion diseases is found in deer and elk?

Chronic wasting disease

Which of the following would you likely see on the surface of a human dendritic cell following phagocytosis of a bacterium?

Class I MHC with dendritic cell antigens and Class II MHC with engulfed bacteria

What would a virally infected skin epithelial cell have on its cell surface?

Class I MHC with skin cell antigens

Which of the following viral genomes could be directly translated to make proteins?

Class IV ssRNA (+) viruses

Which of the following is considered a major category of transmission of disease?

Contact, vehicle, and vector transmission

The most common mode of hepatitis A transmission is

Contamination of food during preparation.

The packaging mechanism of T4 DNA involves cutting of DNA from

DNA concatemers.

Which of the following are likely to be found on an MHC-I protein?

Damaged mitochondrial fragment

When an individual has severe diarrhea, as can occur with cholera, rehydration solution with glucose, salt, sodium bicarbonate, and potassium chloride can be administered. Why is it important to use a solution like this rather than simply giving the individual water?

Diarrhea causes the loss of electrolytes, not just fluids, and it is important to replace the electrolytes as well. Glucose is transported into intestinal epithelial cells, along with sodium, by symporters. It is included as well because glucose is not sufficiently absorbed while sodium is lacking.

A naked virus lacks a capsid.

False

An RNA genome itself serves as mRNA in negative-stranded RNA viruses.

False

Which of the following is the correct progression of a herpes simplex infection?

Direct contact with infected tissue occurs; lesions develop; virus goes dormant in nerve cells; virus is reactivated to cause lesions.

When does MHC-II loading occur?

During the fusion of vesicles containing MHC-II proteins with vesicles containing digested pathogens

What makes agglutination by antibodies possible?

Each antibody has at least two antigen-binding sites.

How can a sufficient humoral immune response occur if a plasma cell only lives for a few days?

Each plasma cell can produce up to 2000 antibodies every second.

Unsanitary and crowded conditions increase the incidence of all of the following diseases EXCEPT

Endemic murine typhus. Plague. Rocky Mountain spotted fever.* Epidemic typhus

Gram-positive bacteria produce endotoxins. (T/F)

False

Rabies infection in humans leads to symptoms a few days after exposure. (T/F)

False

Rod-shaped viruses have icosahedral symmetry while spherical viruses have helical symmetry.

False

Tetanus is highly contagious through person-to-person contact. (T/F)

False

Some viruses, especially animal viruses, have an envelope surrounding their nucleocapsid. This envelope may have viral proteins embedded in it. Why are the viral proteins more readily recognized and targeted by the immune system than the envelope?

Enveloped viruses are often coated with animal cell membrane as they leave the cell. The viral proteins are more readily recognized by the immune system, as they are more distinct from the materials normally found in and on the cells.

Which U.S. government agency monitors water utility reports?

Environmental Protection Agency

Which of the following pairs is NOT correctly matched for Gram reaction?

Epidemic typhus- gram-positive

Food that is heavily salted or candied does not need to be refrigerated. Why not?

Extremely concentrated solutions are very hypertonic and therefore desiccate microorganisms. As a result, there is no need for lower temperatures through refrigeration to slow growth.

A 1-year-old boy was listless, irritable, and sleepy. Capsulated gram-negative pleomorphic bacilli were cultured from his cerebrospinal fluid. His symptoms were caused by

Haemophilus influenzae.

The organism that can cause severe mental retardation in children is

Haemophilus influenzae.

Vaccination for rubella

Has reduced incidence of rubella.

Antibodies are a part of which type of immunity?

Humoral

Which part of the adaptive immune response involves B cells?

Humoral

Which of the following enzymes breaks down the "glue" that holds cells together?

Hyaluronidase

West Nile Virus is an arbovirus that can be transmitted by birds because they develop viremia when infected. In contrast, infected humans cannot spread the disease because they do not develop viremia. Why is viremia associated with the ability to transmit the disease?

If there are no (or only very few) viral particles in the blood, then they are not picked up by vectors feeding on the blood in sufficient amounts to cause infection.

Reheating food to a temperature sufficient to kill bacteria is helpful in making food safer. However, is there a way that one can get food poisoning from food despite its having been heated in this way?

In some cases, toxins may be heat-stable above temperatures that kill bacteria.

Which of the following statements about staphylococcal food poisoning is false?

It can be prevented by boiling foods for 5 minutes before eating.

How does the protozoan Trypanosoma evade detection by the immune system?

It can change the surface antigens frequently, preventing the immune system from tracking it.

Infants born to asymptomatic mothers with recurrent herpes are less likely to acquire herpesvirus at birth than infants born to newly infected mothers because

Maternal antibodies offer protection.

Which of the following statements about Haemophilus influenzae is false?

It has no vaccine.

How is the perishable class determined for food products?

It is determined by water activity: the more water, the more perishable.

Retroviruses become proviruses integrated into the host chromosome soon after infecting the host cell, and can remain there indefinitely. The provirus DNA can then be transcribed and translated by the host cell, making new retroviral RNA genomes, enzymes, and structural proteins. New retroviral virions can then assemble and bud through the host cell membrane continuously over long periods of time. What is one implication of this retroviral life cycle?

It is difficult to completely cure an animal host of the virus, since anti-retroviral drugs will only eliminate circulating virions, not proviruses.

Which of the following statements about rheumatic fever is FALSE?

It is transmitted by the bite of bite of a flea.

Which of the following pairs is mismatched?

Lyme Disease- dog tick* Endemic murine typhus- rat flea West Nile - mosquito Epidemic typhus - louse Rocky Mountain spotted fever - wood tick

Which of the following diseases will antibiotics prevent spread but other treatments are required?

Lyme disease plague typhus anthrax gangrene*

Which cells are involved in a secondary response?

Memory B cells and plasma cells

Which of the following prion diseases was also known as laughing disease?

Kuru

Which of the following bacterial pathogens is found in aquatic environments and is commonly present in air conditioning systems?

Legionella pneumophila

Which of the cells listed below can present antigens on Class II MHC proteins?

Macrophages

From which phrase is the term "prions" derived?

Proteinaceous infectious particles

Why would a body cell that is not a phagocyte need to present antigens?

Non-phagocytic body cells can become infected with a virus.

How do normal prion proteins (PrP) differ from the infectious prion proteins?

Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets.

Where are MHC molecules located on a cell?

On the surface of the cell

Which structure do antigen presenting cells utilize to directly help them present bacterial antigens?

Phagolysosome

Why does the structure of plant and bacterial cells illustrate the reason for having few enveloped viruses that infect these cells?

Plant and bacterial cells contain cell walls that limit the virus from budding out and obtaining the envelope

What is produced by the process of clonal expansion?

Plasma cells and memory B cells

What is the role of plasma cells in humoral immunity?

Plasma cells produce antibodies.

How does the number of infectious prions increase?

Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion.

Which of the following is NOT a characteristic of Bacillus anthracis?

Produces endotoxins* Gram-positive Found in soil Forms endospores

Reverse transcriptase is a(n)

RNA-dependent DNA polymerase.

On July 5, an 11-year-old girl complained of pain in the knuckles of her left hand. During July 6-7, she had increasing pain that extended up to the left shoulder. A throat culture was obtained, and amoxicillin was prescribed. On July 9, she had difficulty swallowing and walking and hallucinations. The throat culture was positive for Streptococcus pyogenes. She was treated with ceftriaxone. On July 11, she was hospitalized with a temperature of 40.7°C, and she could not drink. She developed respiratory distress and tachycardia; she died from cardiac arrest. Fluorescent-antibody testing of brain tissue revealed inclusions in the brain stem. The disease described in the situation is

Rabies.

A fetus died in utero after 4 months' gestation. The probable cause of the fetus's death was

Rubella.

Autoimmune diseases sometimes develop shortly after an infection. This is the case with rheumatic fever. Which of the following is the most likely reason that there is often a relationship between autoimmune disorders and infection?

Some pathogens, like the rheumatogenic strains of S. pyogenes, contain antigens that resemble normal cell surface proteins. As the immune system responds to them, it attacks the cells with similar antigens as well.

Which bacterial microorganism has resistance to heat and high osmotic pressures, and produces a toxin that is heat stable, enabling it to survive up to 30 minutes of boiling?

Staphylococcus aureus

Which of the following virulence factors would be found in Staphylococcus aureus?

Staphylokinase

The DTaP is a vaccine that protects against all but one of the bacteria below. Which bacteria does not belong?

Streptococcal pharyngitis

Which of the following is sensitive to penicillin, an antibiotic that breaks down peptidoglycan?

Streptococcus

The presence of gram-positive diplococci in CSF most likely indicates an infection of

Streptococcus pneumoniae.

The causative agent of streptococcal pharyngitis, also known as "strep throat," is

Streptococcus pyogenes.

A possible complication of measles is

Subacute sclerosing panencephalitis.

The Hepatitis B vaccine that is given to babies is which type of vaccine?

Subunit vaccine

How are superantigens different from other types of exotoxins?

Superantigens cause an overstimulation of the host immune system.

What would be the consequence of deleting the late T4 genes?

T4 capsid proteins would not be made.

Which receptor on the helper T-cell recognizes the specific antigen from an antigen-presenting cell?

TCR

Which of the following pairs is mismatched?

Tetanus - blocks relaxation nerve impulse Gangrene- necrotizing toxin Rabies virus - grows in brain cells Botulism - stimulates transmission of nerve impulse* all of the above are correctly matched.

How might a pathogenic bacterium be affected by antibodies?

The antibodies may block proteins necessary for binding the pathogen to the host, may opsonize the bacterium, or may agglutinate bacteria.

How does a capsule help certain bacteria evade detection by the immune system?

The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign.

Which organelle assists directly with the presentation of MHC-I antigens?

The endoplasmic reticulum

The general steps of the viral lifecycle are similar in most viruses. One major exception, however, is entry into the host cell. How does this step differ between an animal cell and E coli?

The entire virion is taken into an animal cell, but only the viral genome enters E coli.

Plaque assays are often used to estimate the number of virions in a sample of a particular volume (the titer). The count is given as plaque-forming units. Which of the following is NOT generally a concern that must be considered in evaluating the results of plaque assays?

The largest problem is that single viruses may create multiple plaques, resulting in overestimates of the number of viruses present.

Why are the beta-pleated multimers of PrP potentially pathogenic?

The multimers are more stable and resistant to protease.

An individual presents with a pinkish red rash and a red sore throat. Gram-positive cocci are cultured from a throat swab. The cocci are growing in chains. Which of the following is the most likely conclusion?

The patient has scarlet fever.

An example of vehicle disease transmission?

The presence of Listeria on undercooked chicken served for dinner

Where does the name "scrapie" come from?

The prion disorder causes infected sheep to scrape against objects until their skin is raw.

If a human is bitten by an animal that has rabies, then it is recommended that the human receive immune globin (human rabies antibodies) and a rabies vaccination (with inactive virus) as well. Which of the following is the best (and most specific) explanation for why both are recommended in this case?

The rabies antibodies provide a rapid response but short-lived response while the vaccination provides slower but longer-lasting protection.

How is the secondary response different from the primary response in terms of antibody concentration in the blood?

The secondary response is faster and produces more antibodies than the primary response.

What is the hallmark of a conjugated vaccine?

These vaccines contain weakly antigenic elements plus a more potent antigenic protein.

How are immune cells able to detect foreign pathogens?

They are able to detect structures on the surfaces of foreign cells that are not found in the host.

What is a feature of the small fragments presented by MHC-I proteins?

They are small peptides, roughly 8-10 amino acids long.

How do fibrinolysins enhance a pathogen's virulence?

They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.

Cholera can be transmitted by water or food. (T/F)

True

How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system?

They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen.

How are prions different from other infectious agents?

They lack nucleic acid.

How do phagocytes communicate to other cells what they have captured?

They present antigens from engulfed foreign cells.

What is the fate of activated cytotoxic T-cells?

They proliferate into a clone of cells specific to the same antigen; some of these cells then differentiate into long-lived memory T-cells, while others mature to attack infected cells.

What is the role of epidemiology?

To learn how to treat and prevent various diseases.

Tom has a genetic disorder in which he does not synthesize class I MHC proteins or functional NK cells. Which of the following statements would be true for Tom?

Tom would not be able to destroy virally-infected cells.

Which of the following conditions in humans is linked to bovine spongiform encephalopathy?

Variant Creutzfeldt-Jakob disease

Once a person has been infected with Neisseria gonorrhoeae, the individual

acquires no immunity, and thus could be reinfected immediately.

A prophage replicates

along with its host while the lytic genes are not expressed.

Which of the following are the hosts for most enveloped viruses?

animals

An anamnestic response is

another name for secondary response.

If untreated, lyme disease and syphilis are similar in that they __________.

are both caused by spirochetes and are chronic infections that involve the nervous systems

The normal function of the PrP protein in mammals is believed to be:

assisting in normal synaptic development and function.

For bacteriophages and animal viruses ________ is the step in the viral life cycle that determines host cell specificity.

attachment

The term phage is generally reserved for the viruses that infect

bacteria

When determining the number of virus particles in a suspension, why is the number obtained always less than the actual viral titer?

because all of the virus particles do not infect with 100% efficiency

The ingestion of a large number of Vibrio cholerae cells is necessary for infection. Why is such a large concentration of bacteria needed?

because of the low pH in the stomach

Rolling circle replication of the lambda genome differs from replication of a bacterial chromosome in that

bidirectional replication forks are not formed.

When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered

contact transmission.

Legionella pneumophila is generally transmitted by

contaminated water in coolers, pools, and domestic water systems.

An exotoxin that has the ability to kill or damage host cells is referred to as a(n)

cytotoxin

When solute is added to food products, the water activity (aw)

decreases.

Which of the following diseases has a cutaneous form, especially in individuals over 30 years of age?

diphtheria

Serious acute cases of diphtheria are treated with antibiotics and

diphtheria antitoxin.

Bacteriophages genomes are typically composed of

double-stranded DNA.

For a virus to cause a latent infection, it must possess

ds DNA.

Impetigo is due to an infection caused by

either Staphylococcus aureus or Streptococcus pyogenes.

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

endemic

Tetanus develops from a puncture wound because

endospores germinate in anoxic conditions.

The type of Escherichia coli that produces a verotoxin similar to the one produced by Shigella dysenteriae is ________ E. coli.

enterohemorrhagic

What is the medium used in the membrane filter (MF) procedure to differentiate fecal coliforms and Escherichia coli?

eosin-methylene blue agar

Soldiers or refuges in crowded unsanitary conditions are MOST susceptible to which rickettsial disease?

epidemic typhus

Which of the following is NOT a sign of scarlet fever?

fever rash sore throat impetigo*

Streptococcus pyogenes causes all of the following except________.

folliculitis

The size and shape of viral particles is largely governed by the size and packaging of the viral

genome

Staphylococcus aureus is a common foodborne disease, because it

grows on many foods, is present in some humans that work in food processing, and produces several heat-stable enterotoxins.

A positive tuberculin test means a patient

has active disease, has been previously exposed to Mycobacterium tuberculosis, or has a current inappropriate infection.

Staphylococcus aureus is a particularly dangerous organism when in food due to the enterotoxins some species produce. These toxins are dangerous because they are __________.

heat-stable, acid-tolerant superantigen toxins

Regarding the viral membrane of an enveloped virus, the lipids are derived from the ________, and the proteins are encoded by ________.

hosts cell membrane/ viral genes

Several strains of ________ cause genital warts and cervical cancer.

human papillomavirus

The influenza vaccine is an example of a(n)

inactivated killed vaccine.

The presence of specific ________ signals that a given water source might be contaminated with pathogens.

indicator microorganisms

Hantaviruses are most commonly transmitted by ________ of virus-contaminated rodent ________.

inhalation / excreta

The most severe and fatal form of anthrax is

inhalation anthrax.

Viral replication occurs

intracellularly

Antigen processing and presentation

is a way for a cell to give information about its activities.

Enveloped viral membranes are generally ________ with associated virus-specific ________.

lipid bilayers/ proteins

Some bacteriophage possess an enzyme similar to ________, which makes a small hole in the bacterial cell wall, allowing the viral nucleic acid to enter.

lysozyme

A virus that kills its host is said to be

lytic or virulent.

Flour and sugar are classified as ________ foods.

nonperishable

Nearly 90% of all foodborne illnesses are associated with __________.

norovirus, Salmonella, Clostridium perfringens, and Campylobacter jejuni

When packaged in the virion, the complete complex of nucleic acid and protein is known as the virus

nucleocapsid

Legionella pneumophilia can grow in water and is transmitted in aerosols. Which of these has an infection NOT been linked to?

ocean water

A cell that allows the complete replication cycle of a virus to take place is said to be a

permissive host

When a solution composed of bacteria and infectious virions are mixed and spread on an agar plate, ________ form where viruses lyse the host cells.

plaques

Clostridium botulinum is a gram- ________ rod that produces an ________.

positive endospore-forming / exotoxin

The tetanus exotoxin, produced by Clostridium tetani, __________.

prevents inhibitory signals that allow for muscle relaxation

Viral proteins are categorized as early, middle, and late. Early proteins typically are necessary for

production of viral mRNA and copying the viral genome.

Viruses infecting ________ are typically the easiest to grow in the laboratory.

prokaryotes

The inflammatory response to Corynebacterium diphtheriae infection results in the production of a lesion called a(n)

pseudomembrane.

Which of the following diseases CANNOT easily be controlled by vector elimination?

rabies

The primary disease reservoir for plague is

rats.

Psychrotolerant microorganisms can survive and grow at

refrigeration temperatures.

Which of the following is NOT characteristic of a coliform?

resistant to chlorination* facultatively aerobic gram-negative rod shaped

Which of the following enzymes would you expect to find in the virion of a retrovirus, but NOT in a bacteriophage?

reverse transcriptase

Hantavirus pulmonary syndrome is a viral respiratory disease caused by contact with

rodents.

Which of the following is the same for both epidemic typhus and endemic murine typhus?

signs and symptoms

A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n)

superantigen.

Measles viruses are capable of inactivating host defenses by

suppressing the immune system.

The sexually transmitted infection that can lead to infection of the central nervous system if not treated early is __________.

syphilis

The single most important physical sign of primary syphilis is

the chancre.

Expected prevalence of a disease is

the expected occurrence of a disease based on past observations.

Very few preventative measures are taken against anthrax, because

the general population is not exposed to infected materials or animals regularly.

A predisposing factor for infection by Clostridium perfringens is

the presence of dead tissue

Many West Nile virus infections are not properly identified because

the symptoms are often subacute.

The use of ________ is the easiest and most effective way of studying many animal and plant viruses.

tissue or cell culture

The concentration of infectious plaque forming units (pfu) per volume of fluid is known as the

titer

The growth of viruses in a culture is described as a one-step growth curve, because

virion numbers show no increase during intracellular replication and can only be counted after the virions burst from the host cell.

Certain traits that allow pathogens to create infection and cause disease are termed

virulence factors.

Which statement regarding the varicella-zoster virus is FALSE?

-Chickenpox is the result of an initial infection with the herpesvirus varicella-zoster. -Reaction of the latent virus can be caused by stress. -Shingles is a different expression of the virus that causes chickenpox. -Varicella-zoster virus is a herpes virus so its genome is ssRNA*

HIV directly infects T-cells. Why is this problematic for cell-mediated immunity?

Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body.

The causative agent of Lyme disease is ________, which is carried primarily by the ________.

Borrelia burgdorferi / Ixodes sp. (deer tick)

An opportunistic pathogen causes disease ONLY in the presence of normal host resistance. (T/F)

False

Anthrax is an emerging disease for which there is no treatment or vaccine available. (T/F)

False

Which of the following is NOT a gram-negative rod?

Clostridium

Clostridium species that can be associated with gas gangrene include __________.

Clostridium perfringins

Which type of cell directly attacks infected cells?

Cytotoxic T-cells

The Baltimore classification scheme is a useful way to categorize viruses based on their host infectivity. (T/F)

False

Cytokines are produced by which of the following cells?

Helper T-cells

How do helper T-cells and cytotoxic T-cells work together?

Helper T-cells produce cytokines to activate other cells of the immune system.

Meningitis and gonorrhea are caused by

Neisseria species.

What are the possible consequences of viral infection of an animal cell?

Outcomes vary from rapid lysis to persistent infections, latent infections, or cancer.

The etiologic agent of warts is

Papalloma virus.

Which disease did Stanley Prusiner first identify as being caused by prions?

Scrapie

A 45-year-old man has pus-filled vesicles distributed over his back in the upper right quadrant, over his right shoulder, and upper right quadrant of his chest. His symptoms are most likely due to

Shingles

What part of the nervous system is most affected by fatal familial insomnia?

Thalamus

Which of these is NOT caused by herpesvirus?

Smallpox* Cold sores Shingles Chickenpox

Endotoxins are released in large amounts only when cells lyse. (T/F)

True

Escherichia coli is found naturally in the intestines of birds, humans, and animals. (T/F)

True

If a patient is diagnosed with chicken pox, the flat, the fluid filled lesions that appear are known as which of the following?

Vesicles

Which of the following is NOT a way in which viruses are different from living organisms?

Viruses are obligate parasites and no living organisms are obligate parasites.

Which of the following is true about viral infection?

Viruses are very specific in which cells they infect. For a virus to be taken up by a cell, it must find a cell with appropriate receptors on the surface; it cannot be taken up by cells without the appropriate receptors.

For which of the following liver diseases is there currently no vaccine?

Hepatitis C

What component(s) make up the structure of all extracellular virions ?

capsid and genome

A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n)

neurotoxin.