Eukaryotic Microorganisms and Parasites Flashcards
an organism that lives at the expense of another organism
Parasite
another organism, called the
host
Parasites that cause disease are called
Pathogens
study of parasites
PARASITOLOGY
refer to the study of protozoa, helminths, and arthropods that live at the expense of other organisms
PARASITOLOGY
such as ticks and lice, which live on the surface of other organisms
Ectoparasites
some protozoa and worms, which live within the bodies of other
organisms.
Endoparasites
spend at least
some of their life cycle in or on a host.
For example, the protozoan that cau-
ses malaria invades red blood cells
Obligate parasites
normally are free-living, such as
some soil fungi, but they can obtain
nutrients from a host, as many fungi do when they cause skin infections
Facultative parasites
Parasites are also categorized according to the duration of their association with their hosts: such as tapeworms, remain in or on a host once they have invaded it.
Permanent parasites
Parasites are also categorized according to the duration of their association with their hosts: such as many biting insects, feed on and then leave their hosts.
Temporary parasites
Parasites are also categorized according to the duration of their association with their hosts: invade an organism other than their normal host. Ticks that ordinarily attach to dogs or to wild ani- mals sometimes attach to humans; the ticks are then acci- dental parasites.
Accidental parasites
Parasites are also categorized according to the duration of their association with their hosts: refers to a parasite itself having parasites. Some mosquitoes, which are temporary parasites, harbor the malaria parasite or other parasites
Hyperparasitism
insects serve as ? , or agents of transmission, of many human parasitic diseases.
vectors
A vector in which the parasite goes through part of its life cycle is a
biological vector
malaria mos-quito is both a ?
host and a biological vector.
? is a vector in which the parasite does not go through any part of its life cycle during transit. Flies that carry parasite eggs, bacteria, or viruses from feces to human food are?
Mechanical vector
Hosts are classified as ? hosts if they harbor a parasite
definitive
reproduces sexually; they are said to be ? if they harbor the parasite during some other developmental stages.
Intermediate host
? are infected organisms that make parasites available for transmission to other hosts. ? for human parasitic diseases typically are wild or domestic animal
Reservoir hosts
refers to the range of different hosts in which a parasite can mature. Someparasites are quitehost specific—they maturein only one host. T
Host specificity
host defense mechanisms: the formation of an outer covering that protects against unfavorable environmental conditions.
Encystment
faster than the host can make new antibodies
parasite’s surface antigens
cannot react with the parasite’s antigens.
host’s immune system to make antibodies
parasites are out of reach of host defense mechanisms.
Invading host cells
dog heartworm ? , perforates the heart wall and leaves holes in the heart when the worms die and decay.
Dirofilaria immitis
parasites that leave the human body through feces die from
desiccation
Some parasites, such as certain protozoa, undergo ? or multiple fission, in which one cell gives rise to many cells, all of which are infective.
schizogony
one organism has both male and female reproductive systems andbothare functiona
Hermaphroditic
Have chloroplasts; live in moist, sunny environments Examples ex: Euglenoids, diatoms, and dinoflagellates
Plantlike protists
Most are saprophytes; may be unicellular or multicellular
Ex: Water molds; plasmodial and cellular slime molds
Funguslike protists
Heterotrophs; most are unicellular, most are free-living, but some are commensals or parasites Ex: Mastigophorans, sarcodines, apicomplexans, and ciliates
Animal-like protists
usually have a single flagellum and pigmented eyespot
Euglenoids