Deck 23: Eukaryal Microbe Pathogenesis

Question 1

How do trypanosomes evade host defense mechanisms to cause disease?

A) By killing phagocytic cells.
B) By avoiding phagocytosis through capsule production.
C) By replicating inside white-blood cells.
D) By binding the Fc region of immunoglobulins.
E) By an antigenic variation mechanism.

Answer 1

E

Question 2

What do humans ingest in food or water in in order to contact Giardia lamblia?

A) trophozoites
B) gametocytes
C) sporozoites
D) schizonts
E) cysts

Answer 2

E

Question 3

How do many phytopathogenic fungi obtain nutrients from plant host cells?

A) By excreting enzymes to breakdown plant cell walls.
B) By excreting exotoxins to kill plant cells.
C) By stimulating the host cells to excrete sugars.
D) By stimulating the plant to increase photosynthesis.
E) By producing proteins to scavenge nutrients away from the plant.

Answer 3

A

Question 4

The plant pathogen Magnaporthe grisea produces specialized cell structures called ____________ that penetrate the plant cuticle to allow the fungi to invade the plant.

A) hyphae
B) conidia
C) ascospores
D) appressoria
E) cysts

Question 5

What is the causative agent of malaria?

A) a fungus
B) a virus
C) a bacterium
D) a protozoan
E) a helminth

Question 6

The toxin α-amanitin specifically inhibits this.

A) DNA polymerase.
B) RNA polymerase II.
C) cell membrane synthesis.
D) ribosomal function.
E) DNA helicase.

Question 7

Which of these is an example of an opportunistic disease-causing protozoan in AIDS patients?

A) Plasmodium vivax
B) Trypanosoma brucei
C) Giardia lamblia
D) Entamoeba histolytica
E) Toxoplasma gondii

Question 8

Why are trypanosomes not endemic to the United States?

A) Because of an active vaccination program.
B) Because the insect vector is absent.
C) Because the weather is too cold.
D) Because antibiotics keep the disease in check.
E) Because of rigorous water treatment standards.

Question 9

What is the key mechanism in establishing giardial diarrhea?

A) The excretion of an enterotoxin by Giardia.
B) The destruction of intestinal epithelial cells by Giardia.
C) The attachment of Giardia trophozoites to intestinal epithelia.
D) The invasion of Giardia into the intestinal epithelial cells.
E) The production of a cytolytic exotoxin by Giardia.

Question 10

How does the fungus Amanita cause disease?

A) From the ingestion of a potent toxin it produces.
B) Through the invasion of the intestinal mucosa.
C) By inhalation of fungal spores that germinate in the lungs to cause pneumonia.
D) By invading the neuronal tissue and causing disease.
E) Through the invasion of muscle cells.

Question 11

The "definitive host" for Plasmodium falciparum is the host in which it:

A) causes malaria.
B) completes its sexual life cycle.
C) replicates asexually.
D) goes through its complete life cycle.
E) causes a mild form of malaria.

Question 12

AIDS patients are more susceptible to developing pneumonia caused by ___________ than individuals with a normal functioning immune system.

A) Streptococcus pneumoniae
B) Staphylococcus aureus
C) Haemophilus influenza
D) Pneumocystis jiroveci
E) Klebsiella pneumoniae

Question 13

How do spores of the causative agent of Dutch elm disease,Ophiostoma novo-ulmi,spread from a dead infected tree to a non-infected tree?

A) an airborne route of transmission
B) woodpeckers
C) an elm beetle
D) squirrels that live in the dead tree
E) mosquitos

Question 14

Trypanosoma brucei gambiense is the causative agent of what disease?

A) malaria
B) African sleeping sickness
C) yellow fever
D) diarrheal disease
E) dengue fever

Question 15

Candida albicans frequently causes the disease ___________ in AIDS patients,which is characterized by thick white lesions in the mouth.

A) cankers
B) thrush
C) leishmaniasis
D) chancre
E) impetigo

Question 16

Humans typically come into contact with saxitoxin through the ingestion of:

A) contaminated poultry.
B) raw shellfish.
C) contaminated drinking water.
D) raw vegetables.
E) raw beef.

Question 17

Which of these may result in Candida albicans causing disease in immunocompetent people?

A) A change in the microflora because of antibiotic therapy.
B) A change in the antigenicity of the fungus.
C) The production of a potent exotoxin by the fungus.
D) Consumption of contaminated water containing the fungus.
E) Sexual transmission of the fungus.

Question 18

Malaria was eradicated in the United States by 1951.This was primarily accomplished by:

A) successful vaccine development.
B) the use of preventative drugs.
C) successful antibiotic therapy.
D) reduction of the mosquito population.
E) the quarantine of infected individuals.

Question 19

By which route is Giardia lamblia transmitted from infected host to susceptible host?

A) aerosol
B) direct contact
C) vector-borne
D) fecal-oral
E) blood-borne

Question 20

How is Trypanosoma brucei gambiense,transmitted to humans?

A) By a water-borne route.
B) By an aerosol route.
C) Through the bite of a tsetse fly.
D) By direct contact.
E) Through sexual contact.

Question 21

What is the intermediate host in the life cycle of Schistosoma?

A) mosquito
B) tick
C) body louse
D) freshwater snail
E) cat

Question 22

Most of the clinical symptoms observed in an individual with malaria result from this activity.

A) Sporozoite infection of the liver.
B) Sporozoite infection of muscle.
C) Lysis of red blood cells by merozoites.
D) Infection of white-blood cells by merozoites.
E) Parasite infection of the brain cells.

Question 23

Why are individuals who are heterozygous for the sickle cell trait partially protected from developing malaria?

A) They make antibody against the malarial pathogen.
B) Their infected red blood cells become sickled and are destroyed.
C) They develop a strong cell-mediated response against the malarial pathogen.
D) Their red blood cells cannot be infected by the malarial pathogen.
E) Their red blood cells contain very little hemoglobin.

Question 24

The anti-malarial drug chloroquine was used for years to prevent malaria.This drug worked by inhibiting the formation of hemozoin in the parasite,which resulted in:

A) destabilization of the parasitic cytoplasmic membrane.
B) the inhibition of transcriptional processes in the parasite.
C) the inhibition of translational processes in the parasite.
D) accumulation of toxic metabolic products in the parasite.
E) destabilization of the endoplasmic reticulum in the parasite.

Question 25

When an Anopheles mosquito feeds on a person with malaria,it ingests the ___________ form of the parasite.

A) gametocyte
B) sporozoite
C) merozoite
D) oocyst
E) zygote

Question 26

Malaria has influenced human evolution because it has contributed to the development of ______________ in humans.

A) asthma
B) hemochromatosis
C) sickle cell disease
D) diabetes mellitus
E) myasthenia gravis

Question 27

What can result from an ascaris infection in children?

A) Poor nutrient absorption and growth.
B) Damage to the liver.
C) Damage to the heart.
D) Rashes.
E) Damage to the bladder.

Question 28

Name for the infective stage of the malarial parasite in the mosquito.

A) gametocyte
B) sporozoite
C) merozoite
D) oocyst
E) zygote

Question 29

The female Anopheles mosquito serves as the definitive host in the life cycle of the malarial pathogen Plasmodium falciparum.

Question 30

How does transmission of Ascaris lumbricoides occur?

A) By eating improperly cooked pork.
B) Through a respiratory route.
C) By consuming fecal contaminated food or water.
D) Through a blood-borne route.
E) Via an arthropod vector.

Question 31

The fungus Candida albicans is an opportunistic pathogen that may cause disease in some individuals on antibiotic therapy.

Question 32

The merozoite form of Plasmodium sp.specializes in the digestion and use of _____________ as its primary nutrient source.

A) DNA
B) RNA
C) membrane lipids
D) mitochondria
E) hemoglobin

Question 33

α-amanitin has influenced fruit fly evolution because it has contributed to the development of ______________.

A) increased competition for fungal food
B) resistance to parasites infecting the flies
C) immunity to the toxin in organisms that feed on fruit flies
D) lower populations of fruit flies
E) increased mutations in fruit fly genomes

Question 34

What is Ascaris lumbricoides,a helminth that causes ascariasis,commonly called?

A) hookworm
B) roundworm
C) tapeworm
D) pinworm
E) whipworm

Question 35

The fungus Pneumocystis jiroveci primarily causes disease in immunocompromised individuals.

Question 36

The classical symptoms of giardiasis occur when the protozoan enters the bloodstream of its human host.

Question 37

Which of these is used in the most reliable test for the diagnosis of malaria in an individual?

A) An ELISA-based test of a serum sample.
B) Microscopic examination of a stained blood smear.
C) A biopsy of liver tissue.
D) Antibody-coated latex beads to test a blood sample.
E) Tissue culture techniques for growth of the pathogen from a blood sample.

Question 38

What resulted from the deletion of the merozoite surface protein 7 gene (msp7)in a strain of Plasmodium falciparum?

A) Poor replication of the pathogen in the liver.
B) Poor attachment to and invasion of red blood cells.
C) Poor differentiation of merozoite into gametocytes.
D) The disruption of the life cycle in the mosquito.
E) Increased destruction of red blood cells.

Question 39

The parasite Trypanosoma brucei is able to avoid host defense mechanisms through the production of a potent exotoxin.

Question 40

The fungus Pyrenophora tritici-repentis causes disease in wheat.Only strains of P.tritici-repentis that contain the ToxA gene are able to cause disease; other strains are avirulent.The appearance of the toxin gene is recent; how does research indicate this gene was acquired?

A) It is the result of mutation in a pigment gene in the fungus.
B) It is the result of a mutation that up-regulated the expression of the previously non-expressed gene.
C) It was transferred from a pathogenic bacterium to P. tritici-repentis.
D) It was transferred from another pathogenic fungus to P. tritici-repentis.
E) It was acquired through the rearrangement of two other genes in P. tritici-repentis.

Question 41

Some eukaryal pathogens have influenced the evolution of their human host.

Question 42

The form of the Plasmodium parasite that infects the red blood cells is called a merozoite.

Question 43

Explain how the malarial parasite causes disease in humans.

Question 44

The malarial parasite obtains nutrients by digesting ___________ from host red blood cells.

Question 45

Trypanosomes have a complex life cycle that involves both an insect and mammal host.

Question 46

Describe the life cycle of the parasite Giardia lamblia.

Question 47

People develop giardiasis by consuming water containing Giardia lamblia ____________.

Question 48

The life cycle form of the malaria parasite Plasmodium falciparum that is transferred from the mosquito to a human is called a(n)_____________________.

Question 49

Explain how the trypanosome,that causes sleeping sickness,evades the host immune response to cause disease.

Question 50

_______________ are algae that produce potent neurotoxins in large blooms called red tides.

Question 51

The fusing of gametes of the Plasmodium parasite is completed in the human host.