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Microbiology > Eukaryotes (Fungi and Protozoa) > Flashcards

Eukaryotes (Fungi and Protozoa) Flashcards

1
Q

Compare and contrast the characteristics for Fungi and Bacteria? Discuss differences in pH, pressure, obtaining oxygen, and metabolism.

A

-Almost All Molds are Aerobic; most yeast are Faculatative anaerobes: Bacteria vary
-Most fungi can tolerate LOWER pHs and Higher osmotic pressures (ex: higher sugar and salt concentrations) than bacteria
-Fungi requires Less. moisture and Nitrogen for growth than bacteria
-Fungi can metabolize complex carbohydrates for energy (ex: Lignin, a component of wood) that most bacteria cannot use

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2
Q

Differentiate between cell type, cell membrane, cell wall, spores and metabolism in Fungi and Bacteria

A

Fungi:
Cell type: Eukaryotic
Cell Membrane: Sterols present
Cell wall: Glucans; mannans; chitin (no peptidoglycan)
(mannan–> polymer of glucose; mannan-> polymer of mannose)
Spores: Sexual and Asexual reproductive spores
Metabolism: Limited to heterotrophic; aerobic, facultatively anaerobic

Bacteria
Cell type: Prokaryotic
Cell membranel: Sterols absent, except in Mycoplasma
(there is sterol in mycoplasma, since it has NO cell wall; sterols needed to keep mycoplasma stable)
Cell Wall: peptidoglycan layer (made of N-acetly glucosamine and N-acetylmuramic acid)
Spores: Endospores (Not for reproduction); some asexual reproductive spores
Metabolism: Heterotrophic (obtain energy by consuming other organism) , autotrophic (gain energy from sun; photosynthesis) ; aerobic, facultatively anaerobic; anaerobic

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3
Q

What is mycology?

A

Mycology- The study of fungi

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4
Q

What are the harmful and beneficial effects of fungi?

A

Harmful effects of fungi:
-medically, fungal infections have increased over last 20 years due to health-care related infections and more Immunocompromised people (more susceptible to infection) .
(however, only 200 of the >10,000 fungal species are pathogenic)
- commercially, cause an estimated S1 billion dollars in damages to crops annually
Beneficial effects of Fungi:
-Critical for maintenance of food chain/ replenishment of soil nutrients via decomposition of dead plant matter; especially the parts that animals cannot break down
-Nearly all plants depend in Symbiotic fungi termed Mycorrhizae. The fungi and roots in absorbing water and nutrients from soil , while the fungi receives carbohydrates.
-Used by humans as food (mushrooms), and to produce food (bread and citric acid) and drugs (alcohol and penicillin ).

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5
Q

What are the characteristics of fungi in terms of kingdom, nutritional type, cellular arrangement, Food Aquisition method and characteristic features?

A

Characteristics of Fungi
Kingdom: Fungi
Nutritional Type: Chemoheterotroph
Multicellularity: All fungi are Multicellular, Except YEASTS
Cellular Arrangement: Unicellular, filamentous, fleshy
Food Acquisition Method: Absorptive (bring food through membrane; bacteria must be soluble)
Characteristic features: Sexual and asexual spores.

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6
Q

What are different ways of identifying fungi? Which methods are becoming more prevalent to identify fungi in clinical samples?

A

Identification of fungi
-Biochemical tests are used for yeast
-However, multicellular fungi are identified based on physical appearance; including colony characteristics and reproductive spores
(ex: shape/form, elevation and margin (edges)
-Serological and Molecular biology (like PCR) methods are becoming more prevalent to identify both yeast and multicellular fungi in clinical samples.

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7
Q

Discuss the anatomy of Fungi. Include the comparison between the Coenocytic Hyphae and Septate hyphae
What are the functional roles of vegetative and reproductive?Aerial Hypha? How can fungus allow Hyphae to be visible with naked eye?

A

Anatomy of Fungi
-The fungal Thallus or mycelium (vegetative body) consist of filamentous structures called Hyphae.
-Coenocytic Hyphae: Multinucleated, long, continuous cells (like cactus)
-Septate Hyphae: uninucleate, cell like units are created by the formation of septa with a spore in the center. These pores allow the flow of cytoplasm and nutrients throughout the mycelium (mitochondria and nutrients move through; like cubes)
Function Hyphae Compartments:
-Vegetative Hypha: portion that anchors and absorbs nutrients
-Reproductive/Aerial Hypha: bear reproductive spores; projects above the surface of the medium (extends upward)
-A fungus can colonize a substrate and produce masses of hyphae visible to naked eye

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8
Q

Which hyphae is seen in Sordaria Fimicola?

A

Septate hyphae of Sordaria fimicola

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9
Q

What are the characteristics of Yeasts? What are the two main methods of division and how do they differ? What are examples of these Yeasts that divide?

A

Yeasts
-Non-filamentous, UNICELLULAR Fungi
-Typically, spherical or oval
Methods of Division:
-FISSION Yeasts divide SYMMETRICALLY; eg Schizosaccharomyces pome (ex: 1 cells will split into 2 equal sized cells )
-BUDDING Yeasts divide Asymmetrically; ex: Saccharomyces cerevisiae
(bud forms and splits into one larger (mother) cell and one smaller (daughter cell)

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10
Q

What are Pseudohypha? What kind of yeast can undergo pseudohyphal growth?

A

Pseudohypha: Buds that Fail to detach from the parent cell ( and will form pseuodhypha)
-During NITROGEN Fixation S. cerevisiae (budding yeast) can be induced to undergo pseudohyphal growth

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11
Q

Compare and contrast Replicative life span and Chronological life span. How many daughter cells can Budding yeast cell produce?

A

Replicative life span: describes the number of daughter cells a mother cell can produce before reproduction ends and it dies
-replicative life-span is measured in Baker’s Yeast
replicative life-span: model for aging in Mitotically ACTIVE cells
Chronological life span: refers to the length of time that mother cell can survive in a NON-DIVIDING, quiescence-like state, and is proposed to serve as a model for aging of POST-MITOTIC cells in multicellular eukaryotes
-one budding yeast cell, can in time produce produce approximately 24 daughter cells

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12
Q

Why was baker’s yeast chosen to study replicative life-span?

A

Baker’s Yeast is used to study replicative life span because you can tell which cell is mother cell and which is daughter cell
review

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13
Q

What are the two ways of energy production in yeast? Which is the preferred method?

A

Yeast can use O2 or an Organic compound as Final Electron acceptor (RESPIRATION or FERMENTATION) for energy production
-This allows them to inhabit more environments
-Aerobic respiration (using O2) is the PREFERRED method
-in the absence of O2, you can Ferment Carbohydrates to yield Ethanol (EtOH) and CO2

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14
Q

What is the crabtree effect? what are the commercial applications of Yeast Saccharomyces cerevisiae?

A

The Crabtree effect describes the phenomenon whereby the yeast S.cerevisiae, produces EtOH AEROBICALLY in the presence of high External glucose concentrations
-Commercial applications of the yeast Saccharomyces cerevisiae:
- alcoholic beverage production
-Leavening agent for bread production

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15
Q

What makes S.cerevisiae so unique? (Not that important)

A

S. cerevisiae can ferment (regardless of whether there is O2 or not), if given lots of glucose) They can you up glucose fast, and then make ethanol, which inhibits other organisms competitively in environment .
(hence yeast if have O2 will respire; no O2 will ferment

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16
Q

What is the strict definition for Dimorphic Fungi? How does differ from polymorphic fungi and what’s an example?
What can trigger dimorphism in fungi? How is dimorphism determined in pathogenic fungi?

A

Dimorphic fungi: Fungi that growth either as a mold forming hyphae, or as a yeast through Budding (strict definition) (has 2 forms of morphology)
- C. albicans can be considered Polymorphic because it grows as Yeast, pseudohyphae, and hyphae (NOT strictly dimorphic, can do 3 types of forms)
-Dimorphism in fungi is triggered by Temperatures nd CO2 levels
-Dimorphism in pathogenic fungi is predominantly TEMPERATURE Dependent, yeast at 37 degrees C, and mold-like at 25 degrees C.

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17
Q

How Do filamentous fungi reproduce?
Discuss how fungi form spores. What kind of spores can they form?

A

By FRAGMENTATION
-Filamentous fungi can reproduces Asexually by fragmentation of their hyphae
Spore formation: Unlike bacterial endospores, fungi can form true reproduction spores . They detach from their parent and germinate into a new mold
Fungi can form both Asexual and Sexual spores

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18
Q

Differentiate between Asexual spores and Sexual spores? What are telomorphs? Anamorphic?

A

Asexual spores: genetically IDENTICAL to parent; originate from a single hyphae
-Arise through mitosis and subsequent cell division
Sexual spores: arise from the FUSION of Nuclei from two Opposite mating strains of the same fungal species
Telomorph: fungi that reproduce BOTH sexually and asexually
Anamorphs: Fungi that reproduce Only asexually

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19
Q

Discuss the different types of Asexual spores and how they differ?

A

Types of Asexual Spores
1. Conidiospore/conidium;
a spore NOT ENCLOSED IN a SAC
-produced in a chain at the end of a conidiophore
-Easily dispersed (condo = dust)
(conidia is plural)
2. Sporangiospores:
-formed WITHIN A SAC (called sporangium) at the end of an aerial hypha
-one sporangium can contain hundreds of sporangiospores

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20
Q

What are the different Conidia types and what are they based on?

A

Conidia types (based on their Formation)
-Arthroconidia: spore released by fragmentation of a Septate hypha, slightly Thicker than the hypha it was produced from
-Chlamydoconidia: Thick-walled spore formed by Rounding and enlargement within hyphae (round shape)
-Blastoconidia; budding from a parent cell

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21
Q

What are the stages of sexual reproduction in sexual spores? What happens during each stage?

A

Sexual spores
Stages of reproduction:
-Three phase process
1. PLASMOGAMY: union of two haploid cells with mixing of the cytoplasm
2. KARYGOMAY: + and - nuclei fuse (positive and negative )
3. MEIOSIS: Diploid nucleus produces two haploid nuclei (sexual spores), some of which may be genetic recombinants

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22
Q

What determines the phyla for fungi? Explain how fungi are placed in classification. What is Deutermycota?

A

The Sexual Spores produced by fungi determine the phyla
However, many fungi reproduce only Asexually, and cannot be easily placed in a classification based on sexual characters
-Historically, fungi whose sexual cycle had NOT been observed were put in a “holding category” called Deuteromycota

(deutermycota can be referred to as imperfect fungi, since sexual cycles are not known)

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23
Q

What are the medically important phyla of fungi ? how are Deuteromycetes/Fungi imperfect classified?
What are the true fungi and how do they differ from the rest? What can be considered 5th true fungi ?

A

Medically important Phyla of Fungi (in asterisk)
Zygomycota
Ascomycota
Basidiomycota
Deuteromycetes/Fungi Imperfect
other phyla of Fungi are:
-Chytridiomycota, blastocladiomycota, Microsporidia
-Glomeromycota, neocallimastigomycota

Deuteromycetes/Fungi Imperfecta
-*Now being classified based on rRNA *
-Some are Ascomycota or Basidiomycota anamorphs
-Many of the fungi have yet to be reclassified
The fungi Zygomycota, Ascomycota, Basidiomycota and Chytridiomycota are considered the TRUE Fungi (sometimes Glomeromycota is considered the 5th)
-True fungi are Distinct from the structurally similar slime molds and water molds

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24
Q

Discuss the characteristics of the medically important sexual spores (Zygospore, Ascospore and Basidiospore)

A

Sexual spores (medically imporant)
1. Zygospores
-a large DIPLOID spore enclosed in a thick wall
-multi-nucleated diploid reproductive stage resulting from fusion of two haploid nuclei from two cells
2. Ascospore: Spores produced in a Saclike structure called an ascus
-results from the fusion of the nuclei from two cells. HAPLOID spores are produced during meiosis
3. Basidiopsores: HAPLOID spores formed externally on a pedestal (Basidum)

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25
Q

What is mycosis? Explain how mycoses differ from bacterial infections? why are mycoses harder to treat?

A

Mycosis: any fungal disease
Mycoses are generally Chronic (long-lasting) infections because fungi grow slowly (slower than bacteria)
-Since fungi and animals are Both Eukaryotic, drugs that affect fungal cells may also affect animal cells
Thus, fungal infections in animals and humans are often hard to treat
Mycoses are classified into five groups according to site of infection

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26
Q

How are mycoses classified? What are the five types of mycoses and their characteristics?

A

Classification of Mycoses (based on site of infection)
1. Superficial: Limited to outermost layers of skin and hair
2. Cutaneous or Dermatomycoses: extend deeper into the epidermis, as well as invasive hair and nails . Do NOT invade any living tissue
3. Subcutaneous: involves the dermis, subcutaneous tissues, muscle and fascia. Infection occurs by DIRECT Implantation into a puncture wound
4. Systemic: can affect several organs and tissues; INHALATION of spores is the route of transmission. infections usually spread from lungs to other parts of the body.
5. Opportunistic: usually harmless, but become pathogenic in a compromised host (ex; immunocompromised host)

27
Q

What are characteristics of phyla Zygomycota? What are the spores included ?

A

Phyla Zygomycota:
-Called conjugation fungi, sporangium fungi or common mold
-Molds that have coenocytic hyphae
-Asexual spore type: sporangiospores
-Reproduce sexually by means of zygospores
“conjugation fungi” is a sort of a clumsy name for this group. The name reflects the fact that among these fungi, instead go spores being produced on conspicuous spore-producing bodies such as mushrooms or cups, they are produced in very small structures that form when the fungal hyphae “come into conjunction”, or meet one another.
(conjugation fungi a type of sexual reproduction) ?

28
Q

Describe what occurs in the life cycle of a Zygomycete

REVIEW

A

Life cycle of a Zygomycete:
1. Aerial hypha produces a sporangium
2. sporangium bursts to release spores (get sporangiospore)
3. Spore germinates to produce hyphae
4. Vegetative mycelium grows
If Asexual reproduction, life cycle ends at step 4 (where vegetative mycelium grows)
if sexual reproduction occurs,
5. Gametes form at tip of hypha
6. Plasmogamy + Karyogamy occur (where 2 nuclei fuse together)
7. Zygospore forms (zygospore can remain dominant for months ??
8. Meiosis occurs
9. zygotę produces a sporangium
10. spores are released from sporangium
11. Spore germinates to produce hyphae
(also will lead to vegetative mycelium growing)?

29
Q

Describe the characteristics of phyla Ascomycota. What asexual and sexual spores are involved?

A

Phyla Ascomycota
-called Sac fungi (due to ascus)
-includes molds with septate hyphae and some yeast
-Asexual spores: conidiospores
-Sexual spores: ascospore

30
Q

Describe the life cycle of An Ascomycete

A

Life cycle of an Ascomycete:
1. hypha produces a conidiophore
2. Conidia are relased from conidiophore
3. conidium germinates to produce hyphae
4. Vegetative mycelium grows.
For asexual reproduction process ends at step 4?
During sexual reproduction:
5. Plasmogamy occurs (union of two haploid cells)
6. Then karygomay occurs (+ and - nuclei fuse)
7. Meiosis, then MITOSIS occurs (
8. Ascus opens to release ascospores
9. Ascospore germinates to produce hyphae
(then vegetative mycelium grows? )

31
Q

Discuss the phases In life cycle of Ascomyete that are haploid (n), Dikaryotic (n + n), and diploid (2n)
REVIEW

A

In asexual reproduction; stages of conidiophore forming, dispersal of conidiophores, germination and vegetative mycelium growing is HAPLOID (n)
during Plasmogamy (when two different haploid nuclei fuse), the Ascus is DIKARYOTIC (n + n)
-During Karyogamy, you have a DIPLOID (2n) Nucleus (zygote)
karygomay (+ and - nuclei fuse)
After Meiosis, you will have 4 HAPLOID nuclei
-

32
Q

What are the characteristics of Basidiomycota? which asexual and sexual spores are present?

A

Basidiomycota
-called Club fungi derived from the cob shape of the basidium
-includes fungi that produce mushrooms
-possess septate hyphae
-Asexual spore type: some produce conidiophores (others reproduce by Fragmentation)
-Sexual spore: basidiospores

33
Q

Describe the life cycle of basidomycete
REVEIW

A

Life Cycle of Basidomycete:
1. Hypha fragment Breaks off vegetative mycelium
2. Fragment growth to produce new mycelium
3. vegetative mycelium grows
Asexual reproduction ends at step 3?
sexual reproduction begins with step 4:
4. Plasmogamy occurs ( union of haploid cells)
5. fruting structure (“Mushroom”) develops
6. Basidiopsores are formed by Meiosis
7. Basidiospores mature
8. Basidiospores are discharged
9. Basidiospore germinates to produce hyphae

34
Q

Differentiate between the life cycles of zygpomycte, Ascomycete, basidomycete

A

COME BACK TO THIS
Zygomycete : form zygospores sexual reproduction internally
Ascomycete: has haploid, diploid stages
Basidomycete: mainly has dikaryotic stage; forms basidiospore through sexual reproduction Externally

35
Q

What are anamoprhs? What are examples of these?

A

Anamorphs: produce ASEXUAL Spores only
-Penicillium
-Candida albicans

36
Q

What are the beneficial economic effects of fungi ?

A

Beneficial Economic Effects of Fungi:
Used to produce citric acid (since 1914)
-Used to produce bread, wine, beer, and genetically modified to produce a variety of proteins
-Produces the enzyme Cellulase used to digest plant cell walls to produce a clear fruit-juice
-Produces Taxol, an anticancer drug (from 1967 to 1993, the bark of Pacific yew trees was the only source)
-(bark of three yew trees required to treat single patient)

37
Q

What are other beneficial economic effects of fungi (that caused for biological control of pests) ?

A

other beneficial economic effects of Fungi
-Used for biological control of pests
-Kills gypsy moths
-grows on plant roots. Parasitc weevils (insects) that eat the roots die
-foam containing fungi used to kill termites
-feeds on other fungi that feed on soybeans

38
Q

What are the undesirable effects of fungi?

A

Undesirable Effects of Fungi:
-Molds (NOT bacteria) commonly spoil fruits, grains and vegetables
-little moisture on the unbroken surface
-Mold grow on fruit interiors that are TOO acidic, for many bacteria (to grow)
-Molds spoil jams and jellies
-tend to be acidic and have high osmolarity due to sugars
-Fungi have devastated some tree species
-a fungal blight killed almost ALL spreading chestnut trees in the U.S
The dutch elm disease has devastated the American elm population starting in the 1950’s (75% killed)

39
Q

What are lichens? What kingdom are they apart of? What are some of their characteristics ? Where can they be found?

A

Lichens (placed in kingdom Fungi)
Lichens: form a mutualistic relationship between alga (or cyanobacterium) and a fungus
-some of the Slowest growing organisms on Earth
-Require the mutualistic relationship to exist where neither an alga or fungus could exist alone
Typically, first organisms to colonize newly exposed soil and rock
-Also found on trees, concrete and rooftops

40
Q

What are the roles of fungus and alga in a lichen?

A

Alga produces and secretes Carbohydrates
Fungus provides attachment (Rhizines) and protection from desiccation (cortex)
Lichens secrete organic acids to chemically weather rock

41
Q

Describe the anatomical features of lichen. What are the 3 morphological categories of lichen?

A

Anatomical features of lichen: cortex (protective layer on top) ; Medulla (composed of Algal layer (green round structure) and Fungal hyphae, and Rhizine (attach to surface)
3 morphological features of Lichen:
1. Fruticose: have finger like projections
2. Foliose: leaf-like
3. Crustose: flat

42
Q

What are the characteristics of Protozoa?

A

Protozoa:
-UNICELLULAL Eukaryotes
-LACK cell walls
-name means “first animals” to describe animal like nutrition
-inhabit water and soil (some are part of normal microbiome)
-Complex life cycles

(Protozoa are part of kingdom Protista)

43
Q

What are the types of asexual and sexual reproduction found in protozoa? What is a trophozoite? What do Protozoa form to survive certain conditions?

A

Protozoa life cycle
-Trophozoite: Protozoa that are a Feeding and growing form
-All protozoa can reproduce Asexually, by Fission, Budding or Schizogony (multiple fission)
Some protozoa reproduce Sexually;
-Fusion: Gametes fuse to form a Diploid Zygote
-Conjugation: in ciliates, nuclei exchange between two cells.
Many produce a CYST to survive adverse conditions

44
Q

Describe what occurs in the process called Paramecium conjugation

REVIEW

A

paramecium conjugation (occurs in ciliate paramecium)
process:
1. Meiosis of micronuclei; it will divide, and change from diploid nuclei to 4 haploid nuclei
2. Mitosis of ONE of the micronucleus; others disintegrates.
3 of nuclei will disintegrate; while ONE nuclei will Replicate to form 2 new haploid micronuclei
3. Exchange of micronuclei : one of micronuclei move into other cells (swap )
4. Cells separate macronuclei disintegrate; micronuclei fuse
(micronuclei will fuse together to form diploid, then micronuclei will disintegrate)
5. New macronucleus formed from dividing micronuclei
(
DNA content is the same)

45
Q

Explain the process and importance of protozoan encystment and excystment. What are unique features of each?

A

Encystment: simply in its structure, produce a PROTECTIVE capsule called a CYST and become dormant
-permits survival when food, moisture, or oxygen are low, temperatures are unsuitable for toxic chemicals present.
-Important for parasitic protozoa because it allows survival when they are searched outside of one host to get to a new host
-For members of the Phylum Apicomplexa. it serves as a reproductive structure for asexual reproduction (called an oocyst)

Excystment: A RETURN to favorble conditions may stimulate a cyst form to return ints original state
- in parasitic protists, this may occur following ingestion of cyst by a new host program

(trying to escape from cysts)

(excystment :Favorable conditions; while encystment has Unfavorable conditions)

46
Q

Explain protozoan nutrition. Which protozoa are photosynthetic? how do protozoa obtain energy and carbon?

A

Protozoa nutrition
-Require a Large supply of water
-MOST are Aerobic Heterotrophs- although many intestinal protozoa can grow Anaerobically and two groups, Dinoflagellates and Euglenoids are photosynthetic
How do Protozoa obtain energy and carbon?
1) Photoautotrophs
2) absorption- soluble substances transported across the cellular membrane
3) Phagocytosis

47
Q

What are two methods used to facilitate phagocytosis?
How is food digested and waste digested in in Protozoa?

A

2 methods to facilitate phagocytosis:
1. Ciliates employ Cilia to direct food to a CYTOSOME(cell mouth) specialized for phagocytosis
2. Amoebae ENGULF their food by surrounding it with pseudopods and phagocytizing it.
In ALL protozoa, Food is digested in membrane bound vacuoles and waste eliminated through plasma membrane or a specialized ANAL PORE

48
Q

What are the characteristics of the medically important groups and phylums of protozoa? Differentiate between how Carl Woese and Cavalier-Smith classified protozoa?

A

Medically Important Protozoa:
-Carl Woese- kingdom Protista (put all protozoa in this category)
-Cavalier -Smith- Kingom Protozoa and Chromista
Medically important Protozoa:
1. Excavata (Supergroup proposed by Cavalier-Smith consisting of 6-phyla (different phyla) - protozoa + algae) (textbooks used the term Superkingdom)
- Diplomonades (Order)
-Parabasalids (don’t form a single taxonomic group)
-Euglenoza (phylum)
(these three with hyphens next o them are discussed since they have pathogens)
4. Amebae (don’t form a single taxonomic group)
5. Apicomplexa (phylum)
6. Ciliophora (phylum)

49
Q

Describe the characteristics of Excavata. What do the structures look lke?

A

Excavata
-protist species in this group are……
-Asymmetrical, single-celled organisms with a longitudinal feeding groove “excavated” from one side that terminates into the cytosome
-Most are spindle-shaped ad possess flagella

(bacterial prey are consumed by process of phagocytosis)

50
Q

Describe the features of the pathogenic protozoan Diplomonads. Include information about the host, mode of transmission, target cells/tissues, disease produced, and whether they are intracellular parasites

A

Order: Diplomonads: Giardia intestinalis
Diplomonads means “2 bodies”
-Parasite with a Highly reduced mitochondria found in the small intestine of mammals and humans that cause giardiasis- a Diarrheal disease
-Uses a Ventral sucker dish to attach itself to the intestine
-Excreted in feces as a cyst, which permits survival in environment until ingested by next host
-disease diagnoses often based on Identification of cysts in feces
(this parasite, Giardia intestinalis is an EXTRACELLULAR parasite)

51
Q

What are features of the pathogenic protozoan Parabasalids? Include info about host, mode of transmission, target cells/tissues, diseased produced, and whether they are intracellular parasites
What is significance of name Parabasalids?

A

Parabasalids: Trichomonas vaginalis
-Parasite with highly reduced mitochondria found in Vagina and male urinary tract that causes Trichomoniasis (or “trich”) -most infections are asymptomatic but symptoms may develop over time
-Sexually or toilet Facility transmitted.
-Undulating membrane (flaps back and forth)
-NO Cyst stage
-Parabasalids are named because their flagella basal bodies/motors are linked to parabasal fibers that attach to prominent Golgi complexes called parabasal bodies.
(parasite Trichomonas vaginalis are EXTRACELLULAR parasites)

52
Q

Describe the features of the pathogenic protozoan Euglenoza. Include information about the host, mode of transmission, target cells/tissues, disease produced, and whether they are intracellular parasites. What are examples of different species for genus Euglenoza?

A

Euglenozoa: Trypanosoma
-Genus belongs to a group of Euglenozoa called hemoflagellate (blood parasites)
-Transmitting following the Bite of of blood feeding-insects
-found in the circulatory system of the host
-Their long, slender bodies and undulating membrane permit survival in viscous fluid
T. brucei - tetsi fly -African sleeping sickness
T. cruzi- “kissing bug” - chagas disease
(parasite bites you not he face)
-if the insect defecates while biting a human. released trypanosomes can infect the bite wound.

(T. brucei is transmitted in tetsi fly through bug bit (its, saliva; while T. cruzi is transmitted via feces)

53
Q

Explain how Amoeba can engulf food and what happens when food is brought into cell.

A

Amoeba
-Amoebae move and engulf food by extending cytoplasmic structures called pseudopods
-Numerous pseudopods can flow from one side of the Amoeba and the rest of the cell will follow
-Food vacuoles are created when food is brought into the cells

(amoeba is also spelled ameba or amoeba, plural amoebas, amebae, amoebae)

54
Q

Discuss the pathogen Entamoeba and the different species that are apart of the genus. Explain their similarities and how they differ (including their unique characteristics)
-How is parasite transmitted in humans?

A

Amoeba: Entamoeba
-NON-pathogenic E. dispar and Pathogenic E. histolytica BOTH colonize the human intestine and are morphologically IDENTICAL species . However, some E. histolytic will contain ingested red blood cells
-10% of the human population carries E. dispar(non pathogenic)
- E. histolytica expresses a lectin that binds galactose on the plasma membrane of human colonic cells, inducing their lysis and causing dysentery.
human to human transmission occurs via ingestion of cysts excreted in feces of infected person

55
Q

Discuss the similarities for Ameobas: Acanthamoeba and Balamuthia. Also discuss how they differ

A

Amoebas: Acanthamoeba and Balamuthia
-Free-living in water that are NOT transmitted from human to human
-Acanthamoeba: causes RARE, but Severe infections of the eye, skin, and central nervous system
-Balamuthia: causes brain abscesses, most often I immunocompromised people

56
Q

What are the characteristics of the Phylum Apicomplexa?

A

Phylum Apicomplexa
-Most members possess a unique form of organelle that
comprises a type of Nonphotosynthetic plastic called an Apicoplast, and an apical (at the apex) Complex structure that contain enzymes to penetrate the host’s tissue
-Non motile
-Obligate intracellular parasites
-Complex life cycles

57
Q

Differentiate between Sporozoite and Mesozoic

A

Sporozoite: Trophozoite in mosquitos that can infect humans
Mesozoite: trophozoite found in human liver or Red Blood cells

58
Q

What occurs in the life cycle of Plasmodium Vivax? What is the disease that it causes?

A

The life cycle of Plasmodium vivax, the Apicomplexan that causes Malaria
process:
1. Infected mosquito bites human, sporozoites migrate through the blood stream to liver of human.
2. Sporozites undergo schizogony in liver cell; trophozites called Merozoites are produced
3. Merozoites released into blood stream from liver may infect new red blood cells
4. Merozite develops into ring stage in red blood cell
5. Ring stage grows and divides =, producing merozoites.
6. Merozites are released when red blood cell ruptures; some merozites infect new red blood cells and some develop into male and female gametocytes.
Asexual reproduction ends at steep 6.
-Sexual reproduction begins at step 7?
-step 7: Another mosquito bites infected human and digests gametocytes
8. In mosquitos , the digestive tract, gametocytes will unite from zygote
9. resulting sporozoites migrate to salivary glands of mosquito.
9.

59
Q

Differentiate an intermediate host from a definitive host? What are the definitive and intermediate hosts for Plasmodium vivax?

A

Definitive host: an organism that harbors the adult or sexually reproducing form of parasite
Intermediate host: an organism that harbors the asexual reproduction of parasite.
Plasmodium vivax
-Definitive host: mosquito
-Intermediate host: human

60
Q

Describe the features of other Apicomplexan parasites like Babes microti and Toxoplasma gondi

A

Other Apicomplexan parasites:
-Babesia microti- a tick-transmitted, red blood parasite, which causes fever and anemia in immunosuppressed individuals.
-Toxoplasma gondi- the trophozoites (called tachyzoites) produce Sexually and asexualy in cats. Sporozoites (called oocysts) are excreted within feces and if ingested by humans or other animals the sporozoites will emerge as trophozoites, which can ONLY Asexually reproduce in tissues of the new host. Most infected people are asymptomatic or get flu-like symptoms.

61
Q

Differentiate a cyst from an oocyst

A

Cyst: is the DORMANT stage (stopped growth) of bacteria or protozoa which facilitates the survival during UNFAVORABLE environmental conditions
-the cyst is NOT a reproductive cell
Oocyst: is a type of thick-walled cell that is Present in life cycle of protozoa which contains a zygote within it
-Oocyst is a REPRODUCTIVE cell

62
Q

Discuss the characteristics that are under Genus Cryptosporidium for Apicomplexan parasites

A

Other Ampicomplexan parasites
Cryptosporidium (Genus)
-Transmitted to humans through the feces of cows, rodents, dogs and cats
-Humans ingest Cryptosporidium oocysts, which then mature to release sporozoites
-Sporozoites invade small intestine epithelial cells.
-Sporozoites undergo a cycle that eventually releases oocytes that are excreted in feces
-causes diarrhea

63
Q

What are the characteristics of Ciliates? What is significant about Balantidium coli?

A

Ciliates
-Have cilia: arranged in precise rows and move in unison to propel the cell and bring food to the cytochrome (cell mouth)
**Balantidum coli (ko-lee) is the ONLY human parasite; that causes dysentery
-NOT intracellular
-Host ingests cysts, they enter large intestine, and trophozoites are released. Trophozoites destroy host cells and feed on fragments.

Microbiology (18 decks)

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