Microbiology Ch.13- 16

Which of the following statements about the classical pathway of complement activation is FALSE?

C3 is not involved in the classical pathway.

The complement protein cascade is the same for the classical pathway, alternative pathway, and lectin pathway beginning with the activation of

C3.

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

Chronic wasting disease

All of the following bacteria release endotoxin EXCEPT

Clostridium botulinum.

Which of the following statements is FALSE?

Coagulase destroys blood clots.

Which of the following statements is TRUE?

Gamma interferon causes bactericidal activity by macrophages.

Which of the following statements about nosocomial infections is FALSE?

The patient was infected before hospitalization

Aspirin alleviates pain, inflammation, and fever by inhibiting prostaglandins.

True

Histamine and kinins cause increased blood flow and capillary permeability.

True

Activation of C3a results in

acute inflammation.

Margination refers to

adherence of phagocytes to the lining of blood vessels.

The fimbriae of Neisseria gonorrhea and enteropathogenic E. coli are examples of

adhesins and ligands.

DNA made from an RNA template will be incorporated into the virus capsid of

Hepadnaviridae

Viruses that utilize reverse transcriptase belong to the virus families

Hepadnaviridae and Retroviridae.

Which of the following statements about innate immunity is true?

Innate immunity is present at birth

What is the fate of the prophage during the lysogenic stage?

It is copied every time the host DNA replicates.

Which of the following statements about staphylococcal enterotoxin is FALSE?

It is produced by Staphylococcus aureus growing in the host's intestines.

Which of the following statements about M protein is FALSE?

It is readily digested by phagocytes.

The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the hosts antibodies is called

antigenic variation.

Which of the following are best described as short chains of amino acids that are very stable and can have a variety of different antimicrobial activities, such as forming pores in bacterial plasma membranes and inhibiting cell wall synthesis?

antimicrobial peptides

Symptoms of disease differ from signs of disease in that symptoms

are changes felt by the patient.

Transient microbiota differ from normal microbiota in that transient microbiota

are present for a relatively short time.

The normal function of the PrP protein in mammals is believed to be assisting proteins in forming beta-pleated sheets. assisting in normal synaptic development and function. assisting in normal membrane development and function. assisting proteins in forming alpha-helices

assisting in normal synaptic development and function.

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

Kuru

Which of the following statements regarding latent viral infections is true?

Latent infections can persist for years in an individual without causing any symptoms

Which statement regarding the lymphatic system is true?

Lymphatic capillaries possess one-way valves. These valves permit the uptake of fluid from the body but do not allow the fluid to flow back out of the capillaries into the intracellular spaces.

Which of the following is NOT a predisposing factor of disease?

None of the answers are correct; all of these are predisposing factors of disease.

Which one of the following is NOT a zoonosis?

None of the answers is correct; all of these are zoonoses.

Which of the following is NOT a reservoir of infection?

None of the answers is correct; all of these can be reservoirs of infection.

From which phrase is the term "prions" derived?

Proteinaceous infectious particles

How is the lytic cycle different from the lysogenic cycle with respect to the infected host cell?

The host cell dies during the lytic stage.

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

+RNA

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

+RNA viruses

Which of the following places these items in the correct order for DNA-virus replication? 1. Maturation 2. DNA synthesis 3. Transcription 4. Translation

2; 3; 4; 1

Oncogenic viruses

cause tumors to develop.

Lysozyme and the antibiotic penicillin have similar mechanisms of action in that they both cause damage to the bacterial

cell wall.

Which of the following is mismatched?

chemotaxis chemical degradation inside a phagolysosome

Which disease would be potentially propagated in an environment without functional plumbing and in which drinking water is contaminated with sewage?

cholera

An example of a latent viral infection is

cold sores

Which of the following is found normally in serum?

complement

After ingesting a pathogen, lysosomal enzymes produce all of the following EXCEPT

complement.

Continuous cell lines differ from primary cell lines in that

continuous cell lines can be maintained through an indefinite number of generations

Which of the following is NOT utilized to culture viruses?

culture media

Superantigens produce intense immune responses by stimulating lymphocytes to produce

cytokines.

A researcher has performed a prospective study on the disease tetanus. To which specific kind of epidemiological study is this referring?

descriptive

All of the following are components of the inflammatory process EXCEPT

diapedesis.

Patients developed inflammation a few hours following eye surgery. Instruments and solutions were sterile, and the Limulus assay was positive. The patients inflammation was due to

endotoxin.

Bacteria such as E. coli and Salmonella produce invasins that bind host cells, thus causing the cells to

engulf the bacteria.

If one is examining a blood smear from a patient with a parasitic worm infection, which of the following leukocytes would be found in increased numbers (as opposed to a blood smear from a normal patient NOT infected with worms)?

eosinophils

Which of the following is involved in resistance to parasitic helminths?

eosinophils

Which of the following definitions is INCORRECT?

epidemic: a disease that is endemic across the world

The science that deals with when diseases occur and how they are transmitted is called

epidemiology.

All of the following are affects of histamine EXCEPT

fever.

Which type of bacterial enzyme helps spread Streptococcus pyogenes by digesting blood clots?

fibrinolysin

A needlestick is an example of

fomite.

Each of the following provides protection from phagocytic digestion EXCEPT

formation of phagolysosomes.

Lysogenic bacteriophages contribute to bacterial virulence because bacteriophages

give new gene sequences to the host bacteria.

The swelling associated with inflammation decreases when the fluid

goes into lymph capillaries.

Antibiotics can lead to septic shock if used to treat

gram-negative bacterial infections.

Which one of the following does NOT contribute to the incidence of nosocomial infections?

gram-negative cell walls

If a prodromal period exists for a certain disease, it should occur prior to

illness.

Which of the following is an effect of opsonization?

increased adherence of phagocytes to microorganisms

A viroid is a(n)

infectious piece of RNA without a capsid.

The antimicrobial effects of AMPs include all of the following EXCEPT

inhibition of phagocytosis.

Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves

injection of naked nucleic acid into the host cell.

Which of the following is an event that ultimately results in activation of complement C3 by splitting it into C3a and C3b?

interaction of mannose-binding lectin with mannose molecules on a bacterium

Siderophores are bacterial proteins that compete with the host's

iron-transport proteins.

All of the following increase blood vessel permeability EXCEPT

lysozymes.

Which of the following exhibits the highest phagocytic activity?

macrophages

The lectin pathway for complement action is initiated by

mannose on the surface of microbes.

A commensal bacterium

may also be an opportunistic pathogen.

All of the following are methods of avoiding host antibodies EXCEPT

membrane-disrupting toxins

Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a

nosocomial infection.

Which of the following contributes to the virulence of a pathogen?

numbers of microorganisms that gain access to a host, evasion of host defenses, and toxin production

Endotoxins are

part of the gram-negative cell wall.

The definition of lysogeny is

phage DNA is incorporated into host cell DNA

A clear area against a confluent "lawn" of bacteria is called a

plaque.

A viruss ability to infect an animal cell depends primarily upon the

presence of receptor sites on the cell membrane

An infectious protein is a

prion.

Neutrophils with defective lysosomes are unable to

produce toxic oxygen products.

All of the following are effects of histamine EXCEPT

production of antibodies.

Innate immunity includes all of the following EXCEPT

production of antibody.

Enveloped viruses have a layer of lipids surrounding their capsid. This envelope is made mostly of host cell membrane. In which step does the virus acquire this envelope? assembly release synthesis attachment

release During budding release, the virus "steals" some of the host membrane to use for itself.

Which of the following cytopathic effects is cytocidal?

release of enzymes from lysosomes

Which of the following is a fungal zoonosis that can be transmitted by direct contact?

ringworm

Which of the following definitions is INCORRECT?

secondary infection: a long-lasting illness

Endotoxins in sterile injectable drugs could cause

septic shock symptoms.

Koch observed Bacillus anthracis multiplying in the blood of cattle. What is this condition called?

septicemia

Which of the following is classified as a latent disease?

shingles

All of the following are iron-binding proteins found in humans EXCEPT

siderophorin.

Symptoms of intense inflammation and shock occur in some gram-positive bacterial infections due to

superantigens.

Which one of the following steps does NOT occur during multiplication of a picornavirus?

synthesis of DNA

Which of the following would be the first step in biosynthesis of a virus with a - (minus) strand of RNA?

synthesis of double-stranded RNA from an RNA template

Which of the following is NOT a communicable diseases?

tetanus

Injectable drugs are tested for endotoxins by

the Limulus amoebocyte lysate test.

A persistent infection is one in which

the disease process occurs gradually over a long period

The ID50 is

the dose that will cause an infection in 50 percent of the test population.

Which of the following is an example of direct damage due to bacterial infection?

the invasion and lysis of intestinal cells by E. coli

The yeast Candida albicans does not normally cause disease because of

the normal microbiota

All of the following are part of the mechanism of action of alpha and beta interferons EXCEPT

they are effective for long periods.

All of the following are true regarding NK cells EXCEPT

they destroy infected body cells by phagocytosis.

Normal microbiota provide protection from infection in each of the following ways EXCEPT

they produce lysozyme.

In which of the following cases would the Limulus amebocyte lysate (LAL) assay be used?

to ensure that a sterilized medical device is free of endotoxin

Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by

transduction.

The basic mechanism of viral multiplication is similar for all viruses.

true

The following steps occur during multiplication of herpesviruses. Which is the third step?

uncoating

The rise in herd immunity amongst a population can directly attributed to

vaccinations.

All of the following occur during inflammation. What is the first step?

vasodilation

A lytic virus has infected a patient. Which of the following would best describe what is happening inside the patient?

The virus is causing the death of the infected cells in the patient.

What would be the fate of a lytic bacteriophage if the host cell died prior to the assembly stage?

The virus would not be able to infect new hosts

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

Their nucleic acids are injected into the cell.

Which of the following statements is TRUE?

There are at least thirty complement proteins.

hich of the following statements about viral spikes is FALSE?

They are found only on nonenveloped viruses.

Which of the following statements about exotoxins is generally FALSE?

They are resistant to heat.

Which of the following statements provides the most significant support for the idea that viruses are nonliving chemicals?

They cannot reproduce themselves outside a host

Which of the following statements about fixed macrophages is FALSE?

They develop from neutrophils.

How are prions different from other infectious agents? They cause neurological disease. They lack nucleic acid. They lack protein. They cannot replicate.

They lack nucleic acid

How are viruses different from cells? They do not contain protein. They require a host in order to reproduce. They do not contain genetic material. They do not contain enzymes.

They require a host in order to reproduce.

What is the function1 of the structural elements of a virus? To use all of the cell proteins To provide a source of energy for the virus To package and protect the viral genome

To package and protect the viral genome

All of the following pertain to fever EXCEPT that it

accelerates microbial growth by increasing iron absorption from the digestive tract.

The classical pathway for complement activation is initiated by

antigen-antibody reactions.

We sometimes are able to generate antibodies (immune system proteins) that bind to and cover up some of the proteins on the outermost portion of a virus while it is in the bloodstream. This renders the virus unable to reproduce. Which step of viral replication are antibodies directly preventing? assembly uncoating synthesis attachment

attachment

Botulism is caused by ingestion of a proteinaceous exotoxin; therefore, it can easily be prevented by

boiling food prior to consumption

Which of the following diseases is NOT spread by droplet infection?

botulism

The mechanism whereby an enveloped virus leaves a host cell is called

budding.

The most conclusive evidence that viruses cause cancers is provided by

cancer following injection of cell-free filtrates

Which of the following does NOT contribute to the symptoms of a fungal disease?

cell walls

Several inherited deficiencies in the complement system occur in humans. Which of the following would be the MOST severe?

deficiency of C3

You note that the body temperature of one of your patients is starting to increase. As a result, you can infer that all of the following may be occurring in this patient EXCEPT __________.

dilation of blood vessels

The following choices list several types of diseases, along with factors that may contribute to their emergence. Which disease and associated factor do NOT match?

emergence of avian influenza A (H5N1): use of antibiotics

Malaria is an infectious disease caused by infection with a protozoan. In certain tropical regions, malaria is constantly present. We would say that malaria is a(n) _________ disease in these regions.

endemic

Most pathogens that gain access through the skin

enter through hair follicles and sweat ducts.

Twenty-five people developed symptoms of nausea, vomiting, and diarrhea three to six hours after attending a church picnic where they ate a ham and green bean casserole with cream sauce. The most likely cause of this case of food intoxication is

erythrogenic toxin.

All of the following are examples of entry via the parenteral route EXCEPT

hair follicle.

A viral species is a group of viruses that

has the same genetic information and ecological niche

Lysogeny can result in all of the following EXCEPT

immunity to reinfection by any phage.

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

increased susceptibility to disease.

In which of the following patterns of disease does the patient experience no signs or symptoms?

incubation and convalescence

Which of the following mechanisms is used by gram-negative bacteria to cross the blood-brain barrier?

inducing TNF

Each of the following is an effect of complement activation EXCEPT

interference with viral replication.

Biological transmission differs from mechanical transmission in that biological transmission

involves specific diseases.

Innate immunity

is nonspecific and present at birth.

Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called

latent viruses

A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as

latent.

The alternative pathway for complement activation is initiated by

lipid-carbohydrate complexes and C3.

Focal infections initially start out as

local infections.

Activation of C5-C9 results in

lysis of microbial cells.

Bacteriophages derive all of the following from the host cell EXCEPT

lysozyme

Phagocytes utilize all of the following to optimize interaction with microorganisms EXCEPT

lysozyme.

The major significance of Robert Koch's work is that

microorganisms cause disease.

Macrophages arise from which of the following?

monocytes

Which non-specific defense mechanism is mismatched with its associated body structure or body fluid?

mucociliary escalator intestines

The most frequently used portal of entry for pathogens is the

mucous membranes of the respiratory tract

Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use?

mucous membranes only

A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes?

phagocytosis in the inflammatory response

Cholera toxin polypeptide A binds to surface gangliosides on target cells. If the gangliosides were removed,

polypeptide B would not be able to enter the cells.

An envelope is acquired during which of the following steps?

release

Bacteria that cause periodontal disease have adhesins for receptors on streptococci that colonize on teeth. This indicates that

streptococcal colonization is necessary for periodontal disease.

The following steps occur during multiplication of retroviruses. Which is the fourth step?

synthesis of double-stranded DNA

A differential cell count is used to determine each of the following EXCEPT

the number of red blood cells.

Symptoms of protozoan and helminthic diseases are due to

tissue damage due to growth of the parasite on the tissues, waste products excreted by the parasite, and products released from damaged tissues.

Assume you have isolated an unknown virus. This virus has a single, positive sense strand of RNA, and possesses an envelope. To which group does it most likely belong?

togavirus

Which of the following is NOT a cytopathic effect of viruses?

toxin production

All of the following contribute to a pathogens invasiveness EXCEPT

toxins.

The function of the "ciliary escalator" is to

trap inhaled dust and microorganisms in mucous and propel it away from the lower respiratory tract.

In which of the following diseases can gender be considered a viable predisposing factor?

urinary tract infections

Cytopathic effects are changes in host cells due to

viral infections.

A nosocomial infection is

acquired during the course of hospitalization.

Which of the following would be an example of disease transmission via INDIRECT contact?

A student sneezes on her test booklet. The instructor grades it and catches her cold.

Which of the following is NOT a membrane-disrupting toxin?

A-B toxin

All of the following are used by bacteria to attach to host cells EXCEPT

A-B toxins.

TLRs attach to all of the following EXCEPT

AMPs.

Which of the following is NOT a cytopathic effect (CPE) of viruses?

All of the above are possible CPE.

Which of the following can contribute to postoperative infections?

All of the answers are correct.

Which of the following would be an example of an infection initiated via the parenteral route?

An individual contracts hepatitis B from an accidental stick with a contaminated needle.

In which stage does formation of mature viruses occur?

Assembly

Which of the following statements is TRUE?

At least one member must benefit in a symbiotic relationship.

The CDC is located in

Atlanta, GA.

Which of the following statements concerning phagocytosis is true?

Bacteria are digested when the phagosome fuses with a lysosome

The host DNA is usually degraded during which stage?

Biosynthesis

Generally, in an infection caused by a DNA-containing virus, the host animal cell supplies all of the following EXCEPT

DNA polymerase

Which of the following is an example of the symbiotic relationship known as mutualism?

E. coli within the large intestine

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

Enveloped viruses

Which of the following statements about lysogenic conversion is true?

Exotoxin production by bacteria is frequently the result of a lysogenic infection.

Which of the following events might trigger induction of a temperate bacteriophage?

Exposure to UV light

How do normal prion proteins (PrP) differ from the infectious prion proteins? Normal PrP are found in all mammals; infectious PrP are found in only cows. Normal PrP lack nucleic acid; infectious PrP have nucleic acid. Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets. Normal PrP are found on mammals; infectious PrP are found on reptiles.

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

Which statement regarding endotoxins is true?

One consequence of endotoxins is the activation of blood-clotting proteins.

Which of the following statements concerning pathology, infection, and disease is true?

Pathology refers to the study of structural and functional changes that occur in the body as a result of a disease.

In which stage is the viral DNA introduced into the cell?

Penetration

Which of the following is necessary for replication of a prion?

PrPSc

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

Retroviruses

All of the following organisms produce exotoxins EXCEPT

Salmonella typhi.

Which disease did Stanley Prusiner first identify as being caused by prions? Fatal familial insomnia Scrapie Mad cow disease Kuru

Scrapie

In mice, the LD50 for staphylococcal enterotoxin is 1350 ng/kg, and the LD50 for Shiga toxin is 250 ng/kg. Which of the following statements is true?

Shiga toxin is more lethal than staphylococcal enterotoxin.

Which of the following is NOT a verified exception in the use of Kochs postulates?

Some diseases are noncommunicable.

Which statement concerning viral structure is true? All viruses contain an envelope, which is made of lipid, carbohydrate, and protein. Animal viruses usually contain a tail sheath and spikes. The proteins in the envelope are capsomeres. Spikes are found on some viruses. They are very consistent in structure and can be used for identification.

Spikes are found on some viruses. They are very consistent in structure and can be used for identification. Some enveloped viruses have spikes, and they can be used for identification, such as the H and N spikes on the influenza virus.

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

Thalamus

Which of the following statements is FALSE?

The M in MRSA stands for mannitol.

What occurs during viral uncoating? The viral proteins are synthesized. The capsid breaks apart, releasing the viral genome. The nucleic acid breaks apart, allowing for translation. The viral envelope is released.

The capsid breaks apart, releasing the viral genome

Which of the following statements is FALSE?

The prophage makes the host cell immune to infection by other phages.

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

Variant Creutzfeldt-Jakob disease

Which of the following toxins and does NOT match the description?

Vibrio enterotoxin: a superantigen that destroys epithelial cells

*********************************************************************************************************************************************************************************Which of the following is true of viroids? Viroids are short pieces of naked RNA. There are similarities between the base sequences of viroids and exons, resulting in the hypothesis that viroids evolved from exons. Viroids are typically extremely long and contain numerous genes. Viroid is the term for a virus that infects plants.

Viroids are short pieces of naked RNA

How do all viruses differ from bacteria?

Viruses are not composed of cells

Which of the following statements about viruses is FALSE?

Viruses use their own catabolic enzymes

As a health care worker, I am keenly aware of how important it is to avoid harming my patients. I worry about inadvertently transmitting an infectious disease to an already compromised individual. According to the CDC, what is the MOST important thing I can do to avoid this?

Wash my hands before interacting with any patient.

In response to the presence of endotoxin, phagocytes secrete tumor necrosis factor. This causes

a decrease in blood pressure.

Which of the following is a fomite?

a hypodermic needle

Lysogenic viral DNA integrating into the host genome is referred to as

a prophage.

What contributes to antigenic shift in influenza viruses?

a segmented genome

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. the situation is an example of

a zoonosis.

Which of the following is NOT an example of microbial antagonism?

bacteria causing disease

Which of the following is NOT used as a criterion to classify viruses?

biochemical tests

Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps?

biosynthesis

A chill is a sign that

body temperature is rising.

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. The method of transmission of the disease in the situation was

vehicle

A cold transmitted by a facial tissue is an example of which form of disease transmission?

vehicle transmission

In what year did Stanley Prusiner discover prions?

1982

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. The etiologic agent of the disease in the situation is

Coxiella burnetii.

Which of the following is true regarding cultivation and isolation of animal viruses? Viruses can be easily grown in liquid culture without any other organisms present. The preferred and widely used method of viral isolation and growth is via growth in an embryonated egg. Mouse models are available for virtually all human viral infections and can be routinely used for vaccine development. Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host.

Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host. Cell culture produces the most reproducible results.

Which of the following is true concerning a lysogenic viral replication cycle? During lysogeny, the viral DNA is present as a circular plasmid. Lysogenic infections are similar to persistent infections, in that virus is constantly produced. During lysogeny, the viral genome integrates into the host DNA, becoming a physical part of the chromosome. Once the lysogenic portion of the cycle has begun, virus is never produced again.

During lysogeny, the viral genome integrates into the host DNA, becoming a physical part of the chromosome. It is inactive at this time, and virus is not produced.

All of the following protect the skin and mucous membranes from infection EXCEPT

HCl.

Which of the following statements about biological transmission is FALSE?

Houseflies are an important vector.

________________ is/are always present in an individual's blood. However, in the absence of infection, it is in an inactive form.

Kinins

Gram-negative septic shock results from the following events. What is the second step?

LPS is released from gram-negative bacteria

Which of the following statements about adherence is true?

Most bacterial adhesins are glycoproteins or lipoproteins.

Which of the following pairs is mismatched?

None of the pairs is mismatched.

Which of the following statements concerning prion diseases is true? Prion diseases affect humans but not other animals. Prion diseases are always inherited. Prion diseases affect brain function but do not affect the morphology (overall appearance) of brain tissues. Normal host cellular prion proteins (PrPC) are converted into scrapie proteins (PrPSc).

Normal host cellular prion proteins (PrPC) are converted into scrapie proteins (PrPSc).

How does the number of infectious prions increase? Prions reproduce by binary fission. Prions form multimers which can then form more single copies of the prion protein. Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion. Prions reproduce by mitosis.

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

Most RNA viruses carry which of the following enzymes?

RNA-dependent RNA polymerase

Which of the following statements concerning viruses is true? Viruses contain both DNA and RNA, and they undergo binary fusion. The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach. Viruses are usually about the same size as bacteria. Viruses possess enzymes for protein synthesis and ATP generation.

The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach. Attachment of the virus to the host cell (the first step in the viral life cycle) requires binding of complementary molecules on the virus and host cell

Which of the following does NOT contribute to the emergence of infectious diseases?

The emergence of infectious diseases can be attributed to all of these

What happens to the packaged DNA of a specialized transduced phage when it infects a new recipient cell? The DNA begins to replicate without integrating into the host chromosome. The host DNA integrates, with the prophage, into the new recipient chromosome. The DNA is chewed up by enzymes found in the recipient cell.

The host DNA integrates, with the prophage, into the new recipient chromosome.

Why are the beta-pleated multimers of PrP potentially pathogenic? The multimers are more stable and resistant to protease. They are not detected by other organisms. They are found on the surface of immune cells, resulting in damage to the immune system. They repress the immune system.

The multimers are more stable and resistant to protease.

Koch's postulates established criteria for proving that a specific organism causes a specific disease. Which of the following is NOT one of the criteria given by Koch's postulates?

The pathogen must be isolated from inoculated animals and must be different from the original organism.

Which of the following statements about the development of infectious diseases is correct?

The period of convalescence is the time during which the person regains health and fully recovers (back to the pre-disease state).

Where does the name "scrapie" come from?

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

How does specialized transduction differ from regular lysogeny? The resulting bacteriophage from specialized transduction cannot infect a new host cell. The resulting bacteriophage from specialized transduction does not contain any viral DNA. The prophage is not excised during specialized transduction. The prophage in specialized transduction carries with it pieces of the host chromosomal DNA. SubmitMy AnswersGive Up

The prophage in specialized transduction carries with it pieces of the host chromosomal DNA.

How can specialized transduction contribute to the transfer of antibiotic resistance genes in a bacterial population? The phage lyses the bacterium and releases resistance genes into the local environment, which can then be taken up by recipient cells. The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA. The phage causes the destruction of any antibiotic present during the specialized transduction process.

The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA.