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79 Cards in this Set

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Name four distinguishing characteristics of protozoa.
1. absence of a cell wall
2. ability to move by locomotor organelles or gliding system during all or part of their life cycle
3. heterotrophic
4. primarily asexual
Classes of protozoa are separated by what characteristic?
Means of locomotion
Name the four classes of protozoa.
1. Sarcodina
2. Mastigophora
3. Ciliophora
4. Sporozoa
What means of locomotion do the sarcodina class of protozoa use?
Pseudopods resulting from the streaming of ectoplasm
What means of locomotion do the mastigophora class of protozoa use?
One or more whiplike, thin structures called flagella
What means of locomotion do the Ciliophora class of protozoans use?
Short hairlike projections called cilia
What means of locomotion do the sporozoa class of protozoans use?
Only immature members have locomotor organelles; these organelles vary between species
Which class of protozoa only have parasitic species?
Sporozoa
Give a(n) example(s) of both free-living and parasitic species of the protozoan class sarcodina.
Free-living: Amoeba proteus
Parasitic: Entamoeba histolytica
Give a(n) example(s) of free-living genera and parasitic species of the protozoan class mastigophora.
Free-living: (genera) Cercomonas, Heteronema, and Wuglena
Parasitic: (species) Trichomonas vaginalis, Giardia lamblia, and Trypanosoma
Give a(n) example(s) of both free-living and parasitic species of the protozoan class ciliophora.
Free living: Paramecium caudatum
Parasitic: Balantidium coli
Which protozoan parasites do not require an intermediate host?
Entamoeba histolytica, Balantidium coli, and Giardia lamblia
Name the parasitic protozoan of the class Sarcodina that causes amebic dysentery. Upon integestion of this organism, the mature quadrinulceated cyst wall disintegrates and the nuclei divide, producing eight active trophozites (metabolically active cells) that move to the colon, where they establish infection.
Entamoeba histolytica
This ciliated parasitic protozoan exhibits a life cycle similar to that of E. histolytica except that no multiplication occurs within the cyst. It resides primarily in the lumen and submucosa of the large intestine causing intestinal ulceration and alternating constipation and diarrhea.
Balantidium coli
This parisitic protozoan flagellate is responsible for the induction of abdominal discomfort and severe diarrhea. Diagnosis is made by finding cysts in the formed stool and both cysts and trophozoites in the diarrhetic stool.
Giardia lamblia
Name the mastigophoric hemoflagellate responsible for various forms of African sleeping sickness.
Trypanosoma
What is required for the Trypanosoma to complete its cyclic development?
Two hosts: a vertebrate host and an invertebrate, blood-sucking insect host
Which class of protozoa demonstrate the greatest degree of cyclic complexity?
Sporozoa (composed of exclusively obligate parasitic forms)
Which genus of Sporozoa is responsible for malaria in both humans and animals?
Plasmodium
Which two hosts does a Plasmodium require to complete its life cycle? Which is the definitive host?
Human and female Anopheles mosquito; female Anopheles mosquito is the definitive host
What happens after a human is bitten my a mosquito infected by one of the Plasmodium species.
The parasites pass rapidly from the blood to the liver, where the infect the parenchymal cells (pre-erythrocytic stage). There they develop asexually by a process called schizogony, producing merozoites. Merozoites are released from the ruptured liver cells and cell infect red blood cells (erythrocytic stage).
Name the morphological forms that a species of the Plasmodium genus go through during their asexual development. (6)
Signet rings, trophozoites, schizonts, segmenters, merozoites, and gametocytes.
(SIGmonds TROPHy Shows Shiny Monkeys and Gorillas)
Which asexual form of the Trypanosoma species is capable of infecting other blood cells or liver cells?
Merozoites
How is the life cycle of the Trypanosoma species completed?
Ingestion of the microgametes (male) and macrogametocytes (female) by another mosquito during a blood meal initiates the sexual cycle called sporogamy. Male and female gametes five rise to a zygote in the insects gut which is transformed into an ookinete that burrows through the gut wall to form an oocyst in which the sexually mature sporozoites develop.
Distinguish between the pre-erythrocytic and erythrocytic stages of the malarial parasite.
Pre-erythrocytic stage occurs in the liver, this is where the parasite develops asexually producing merozoites. Erythrocytic stage occurs when the merozoites infect the blood cells and goes through a series of morphological stages.
What is the branch of microbiology that deals with the study of fungi (yeast and molds)?
Mycology
Name the four classes of true fungi.
1. Zygomycetes
2. Ascomycetes
3. Basidiomycetes
4. Deuteromycetes (aka Fungi Imperfecti)
What characteristic is used to separate classes of fungi?
Their sexual modes of reproduction
Why is the Deutoromycete class also know as Fungi Imperfecti?
No sexual reproductive phase has been observed
Describe the sexual spores of Zygomycetes.
External and uncovered
Which types of molds are included in the zygomycete class?
Water, bread, and terrestrial molds
Describe the sexual spores of Ascomycetes.
Sexual spores, called ascospores, are produced in a saclike structure called an ascus
What is included in the class ascomycetes?
Yeasts and molds
Describe the sexual spores of basidiospores?
The reproductive spores, called basidiospores, are separate from specialized stalks called basidia
What are included in the class basidiomycete?
Fleshy fungi, toadstools, mushrooms, puffballs, and bracket fungi
True or false?
Fungi are limited to metabolizing a limited number of organic substrates.
False.
They can metabolize a wide variety of organic substrates.
Are fungi heterotrophic or autotrophic?
Heterotrophic
Name some of the ways fungi are a benefit to humans.
They play a vital role in decomposing dead animal and plant tissue maintaining fertile soil. They can also be used industrially to produce beer, wine, bakery products, cheeses, antibiotics, among other things.
Which class do most of the pathogenic fungi belong to?
Deuteromycetes
Name the two groups of pathogenic Deuteromycetes and the areas that they infect.
Superficial mycoses; cause infections of the skin, hair, and nails (ex: ringworm infections)
Systemic mycoses: cause infections of the subcutaneous and deeper tissues such as the lungs, genital areas and nervous system
Name the only class of fungi that has nonseptate mycelium.
Zygomycetes
What are the major fungal organisms that can be seen by the naked eye?
Molds
An "intertwining branching mat" is used to describe what?
Mycelium
What are the filaments that make up the mycelial mat called?
Hyphae
What is vegetative mycelium?
When most of the mycelium mat grow on or in the surface of the nutrient medium.
What is aerial mycelium?
When the mycelium mat grows upward from the mat.
What type of media is needed to grow molds?
Selective media such as Sabouraud agar or potato dextrose agar
What is it about the Sabouraud agar and potato agar that facilitate mold growth?
Their low acidity (pH 4.5 ti 5.6)
What temperatures do most molds grow at?
Room temperature (25 degrees C)
What is advantageous about observing mold colonies on an agar plate?
It allows you to observe the variations of gross colonial morphology which plays a major role in the identification of the filamentous fungi
What is yeast?
Nonfilamentous, unicellular fungi
How does the size of yeast compare to bacteria?
Yeasts are 5-10 times larger
How does yeast reproduce?
Asexually by budding or by fission; also sexually
Name some ways in which yeasts are important to humans.
They are used as leavening agents in dough, for brewing, fermentation of grape juice and their high vitamin content makes them valuable as food supplements
Which yeast is responsible for urinary tract and vaginal infections and infections of the mouth?
Candida albicans
What are urinary tract and vaginal infections that are caused by Candida albicans called?
Moniliasis
What are infections of the mouth caused by Candida albicans called?
Thrush
What are the significance of buds in the reproductive activities of yeast cells?
A bud is an outgrowth from the parent cell that pinches off during budding, a form of asexual reproduction
What is the significance of an ascospores in the reproductive activities of yeast cells?
During sexual reproduction two sexual spores conjugate, giving rise to a zygote (diploid cell) which then divides by meiosis producing four new haploid nuclei which are sexual spores called ascospores
What is the significance of an ascus in the reproductive activities of yeast cells?
The ascus contains the ascospores; it will rupture and release the ascospores allowing them to conjugate, starting the cycle over again
What can be used to identify different genera of yeasts?
Cultural characteristics, type of reproduction, and the fermentative activities
Because of their limited and simplistic structure how are viruses chemically defined?
Nucleoproteins
What is needed in order to view a virus?
An electron microscope
What are bacterial viruses called?
Bacteriophages, or just phages
List the five sequential events involved in phage infection.
1. Adsorption 2. Penetration
3. Replication 4. Maturation
5. Release
What happens during the adsorption phase?
Tail fibers of the phage particle bind to receptor sites on the host's cell wall
What happens during the penetration phase?
Spiral protein sheath retracts and an enzyme, early muramidase, perforates the bacterial cell wall enabling the phage nucleic acid to pass through the hollow core into the host cell's cytoplasm
What happens during the replication phase?
The phage genome subverts the cell's synthetic machinery, which is then used for the production of new phage components
What happens during the maturation phase?
New phage components are assembled and form complete, mature virulent phage particles
What happens during the release phase? (Virulent phage)
Late muramidase (lysozyme) lyses the cell wall, liberating infectious phage particles that are now capable of infecting new susceptible host cells
How is temperate phage different from a virulent phage?
The infected host cell continues to function as normal until exogenous physical agents such as ultraviolet, ionizing radiation, or chemical mutagenic agents induces lysis
What are the bacterial host cells that have the temperate phage's nucleic acid incorporated in it called?
Lysogenic cells
How do animal viruses differ from bacteriophages?
They lack the spiral protein sheath, base plate and tail fibers; their shapes are helical or cuboidal
Why are some animal viruses designated as "naked viruses"?
Because they are composed soley of nucleocapsids
What are enveloped viruses?
Their nucleocapsid is surrounded by a lipid bylayer that may have glycoproteins associated with it
How does adsorption differ in an animal host from a bacterial host?
Adsorption occurs to receptor sites that are located on the cell membrane of the host cell instead of the cell wall as in the bacterial host
How does pentetration differ in an animal host from a bacterial host?
Penetration is accomplished by endocytosis in an animal host, the entire virus enters the host cell; in bacteria only the enzyme, early muramidase, goes through the cell wall
What is required for endocytosis to occur in an animal host cell?
Energy and compliment receptor site
How is the latent period different in an infected bacterial cell from an infected animal cell?
The latent period in an infected bacterial cell is much shorter; minutes vs. hours or days