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Microbiology > Chapter 5 > Flashcards

Chapter 5 Flashcards

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Biology 101 flashcards
1
Q

History of Eukaryotic Cells

A

-Originated 2 billion years ago
-Endosymbiotic Theory (Lynn Margulis)
>Eukaryotic cells resulted from one prokaryotic cell engulfing another prokaryotic cell
-Evidence:
>some eukaryotic organelles resemble prokaryotic cells:
-Mitochondria + Chloroplasts are rod-shaped, measured in ums, have 70S ribosomes, have own DNA that is similar to prokaryotic DNA

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2
Q

Endosymbiotic Theory

A
  • Lynn Margulis

- Eukaryotic cells resulted from one prokaryotic cell engulfing another prokaryotic cell

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3
Q

Endosymbiotic Theory: Evidence

A

Some Eukaryotic organelles resemble prokaryotic cells
-Mitochondria + Chloroplasts are rod-shaped, measured in ums, have 70S ribosomes, have own DNA that is similar to prokaryotic DNA

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4
Q

Eukaryotic Organisms Studied in Microbiology

A
  1. Protozoa: Unicellular, A few Colonial
  2. Fungi + Algae: May be unicellular, colonial, or multicellular
  3. Helminths (parasitic worms) + Arthropods (animal vectors of disease): multicellular except reproductive stages
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5
Q

External Structure of Eukaryotic Cell: Locomotor appendages: Flagellum(a)

A
  • long, sheathed cylinder containing microtubules in a 9+2 arrangement
  • composed of protein tubulin
  • 10x thicker than prokaryotic flagella
  • function in motility
  • Mechanism of Action: wavelike
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6
Q

External Structures of Eukaryotic Cell: Locomotor appendages: Cilia

A
  • similar in overall structure to flagella, but shorter and more numerous
  • found only on a single group of protozoa and certain animal cells-function in motility, feeding, and filtering
    ex: paramecium
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7
Q

External Structures of Eukaryotic Cell: Glycocalyx

A
  • an outermost boundary that comes into direct contact with environment
  • usually composed of polysaccharides
  • appears as a network of fibers, either a slime layer or a capsule
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8
Q

Significant functions of the Glycocalyx

A
  • adherence (attachment)
  • protection from toxic chemicals
  • prevents desiccation
  • functions in signal reception
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9
Q

Beneath the Glycocalyx

A
  • Fungi and most algae have a thick, rigid cell wall

- Protozoa, a few algae, and all animal cells lack a cell wall and have only a membrane

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10
Q

Cell Wall

A

-rigid, provides structural support and shape

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11
Q

Cell wall of Fungi

A

-have thick inner layer of polysaccharide fibers composed of chitin

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12
Q

Cell wall of Algae

A

-varies in chemical composition; may be cellulose, pectin, mannans, silicon dioxide, and calcium carbonate

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13
Q

Cell wall of Animals

A

no cell wall

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14
Q

Internal Structure of Eukaryotic Cell: Nucleus

A
  • control center of the eukaryotic cell
  • envelope composed of two parallel membranes separated by a narrow space; perforated with pores
  • contains species specific number of chromosomes
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15
Q

Internal Structure of Eukaryotic Cell: Nucleolus

A

-dark area for rRNA synthesis and ribosome assembly

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16
Q

Internal Structure of Eukaryotic Cell: Endoplasmic Reticulum

A

Two types:

  1. Rough Endoplasmic Reticulum (RER)
  2. Smooth Endoplasmic Reticulum (SER)
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17
Q

Rough Endoplasmic Reticulum (RER)

A
  • originates from the outer membrane of the nuclear envelope
  • extends in a continuous network through cytoplasm;
  • proteins synthesized on ribosomes;
  • shunted into the ER for packaging and transport; first step in secretory pathway
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18
Q

Smooth Endoplasmic Reticulum (SER)

A
  • closed tubular network without ribosomes;

- functions in nutrient processing, synthesis, and storage of lipids

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19
Q

Internal Structure of Eukaryotic Cell: Golgi Apparatus

A
  • modifies, stores, and packages proteins
  • secretes vesicles
  • consists of a stack of flattened sacs called cisternae
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20
Q

Internal Structure of Eukaryotic Cell: Mitochondria

A
  • function in energy production
  • outer membrane and an inner membrane with folds called cristae
  • cristae hold the enzymes and electron carriers of aerobic respiration
  • divide independently of cell
  • contain DNA and 70S prokaryotic ribosomes
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21
Q

Internal Structure of Eukaryotic Cell: Chloroplast

A
  • convert the energy of sunlight into chemical energy through photosynthesis
  • found in algae and plant cells
  • outer membrane covers inner membrane folded into sacs, thylakoids, stacked into grana
  • primary producers of organic nutrients for other organisms
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22
Q

Internal Structure of Eukaryotic Cell: Ribosomes

A
  • 80S
  • composed of rRNA and proteins
  • scattered in cytoplasm or associated with RER
  • function in protein synthesis
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23
Q

Fungi

A
  • Eukaryotic Cell
  • Single or Multicellular
  • Heterotrophic
  • Mycology
  • Mycotoxins (produced by pathogenic fungi)
  • Facultative parasites
  • Saprophytes (saprobes); required dead or dying host
  • Nutrition: send out exoenzymes to break down material; absorb digested material
  • Decomposers or recyclers
  • Cell wall: Chitin
  • Membrane: Ergosterol
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24
Q

Fungi: Dimorphism

A

ability to alter structure when changing environments

25
Q

Fungi: Structure

A
  • Mycelium- mass of hyphae (body)
  • Hyphae- fungal filaments
  • Septate- separated by walls
  • Coenocytic- no walls
  • may be multinucleated
  • Vegetative or Reproductive (aerial)
26
Q

Fungi: Reproduction

A
  • asexual

- sexual

27
Q

Fungal Structure: Yeast

A

soft, uniform texture and appearance

-reproduce through an asexual process called budding

28
Q

Fungal Structure: Filamentous Fungi

A

mass of hyphae called mycelium; cottony, hairy, or velvety texture

  • Hyphae may be divided by cross walls- Septate
  • Hyphae may be without walls- Coenocytic
  • Vegetative Hyphae- digest and absorb nutrients
  • Reproductive hyphae- produce spores for reproduction
29
Q

Fungal Reproduction

A

-Sexual reproduction- spores are formed following fusion of two different strains and formation of a sexual structure
(zygospore, ascospore, and basidiospores)
-Sexual spores- and spore-forming structures are used for identification and are the usual basis for classification

  • Asexual reproduction- spores are formed through budding or mitosis; two subtypes of asexual spores: conidia and sporangiospores
  • Asexual spores are used for identification
30
Q

Fungal Reproduction: Sexual Reproduction

A

spores are formed following fusion of two different strains and formation of a sexual structure

  • Zygospores, ascospores, and basidiospores
  • sexual spores and spore-forming structures are used for identification and are the usual basis for classification
31
Q

Fungal Reproduction: Asexual Reproduction

A

spores are formed through budding or mitosis; two subtypes of asexual spores: conidia and sporangiospores
-asexual spores are used for identification

32
Q

Subtypes of Asexual Mold Spores

A

a. Sporangiospore

b. Conidia

33
Q

Fungal Classification

A

Kingdom Eumycota is subdivided into several phyla based upon the type of sexual reproduction:

  • Phylum Zygomycota- zygospores; mostly sporangiospores and some conidia
  • Phylum Ascomycota- ascospores; conidia
  • Phylum Basidiomycota- basidiospores; conidia
  • Phylum Chytridomycota- flagellated spores
34
Q

Fungi that produce only Asexual Spores

A

Imperfect or Deuteromycota

  • phylum of unknown origin
  • don’t have sexual spore yet
35
Q

Fungal Classification: Phylum Zygomycota

A

zygospores; mostly sporangiospores and some conidia

36
Q

Fungal Classification: Phylum Ascomycota

A

ascospores; conidia

37
Q

Fungal Classification: Phylum Basidiomycota

A

basidiospores; conidia

38
Q

Fungal Classification: Phylum Chytridomycota

A

flagellated spores

39
Q

Formation of Zygospores

A

-Phylum Zygomycota
-Sexual spore: zygospore
-Asexual spore: Sporangiospores
-Zygospore germinates, forms mycelium, that gives rise to sporangium.
Meiosis of diploid cells of sporangium result in haploid nuclei that develop into sporangiospores

40
Q

Production of Ascospores

A

-Phylum Ascomycota
-Sexual spore: ascospore
-Asexual spore: conidia
-opposite mating strands (+and-)
zygote nuclei that undergoes meiosis prior to formation of asci
-ascospores are produced, bunch of chemicals, spores explode out the top and go all over the place

41
Q

Examples of Ascomycetes

A
  • Penicillium
  • Saccharomyces
  • Histoplasma
  • Microsporum
  • Coccidioides
  • Candida
  • Stachybotrys
  • Pneumocystis
42
Q

Formation of Basidiospores in a mushroom

A

Phylum- basidiomycota
Sexual spore: basidiospore
Asexual spore: conidia
-pair of nuclei fuse to form diploid nucleus, diploid nucleus undergoes meiosis to produce four haploid nuclei

43
Q

Examples of Basidiomycetes

A
  • mushrooms
  • puff balls
  • bracket fungi
  • Rusts (plant fungi)
  • Smuts (plant fungi)
  • Cryptococcus
  • Claviceps
44
Q

Fungal Identification

A

-Isolation on specific media (like acidic media)

  • Macroscopic and Microscopic observation of:
  • Asexual spore-forming structures and spores
  • Hyphal type
  • Colony texture and pigmentation
  • Physiological characteristics
  • Genetic Makeup
45
Q

Adverse Effects of Fungi

A
  • Mycoses- fungal infections
  • Allergies- fungal cell wall substances trigger reactions
  • Toxin production- aflatoxin, ergot toxin; neurological effects
  • Destruction of crops and food storages
46
Q

Beneficial Impact of Fungi

A
  • Decomposers of dead plants and animals
  • Form associations with plant roots (mycorrhizae; helps plant get nutrients)
  • Aid in digestion in guts of herbivores
  • Sources of antibiotics, alcohol, organic acids, vitamins
  • Used in making foods (beer, wine, bread, soy sauce, blue cheese, cured meats)
  • Used in genetic studies (Recombivax; vaccination (hep B)
47
Q

Fungi: Mycoses

A

fungal infections

  • Systemic (whole body; inhaling)
  • Subcutaneous (under skin; requires puncture)
  • Cutaneous (in and on skin)
48
Q

Mycoses: Systemic

A

whole body; inhaling

  • Coccidioido- Coccidioidomycosis (in desert areas; carried with dust from desert)
  • Histoplasma- Histoplasmosis (common in cave explorers, type of pneumonia)
49
Q

Mycoses: Subcutaneous

A

under skin; requires puncture

-Sporothrix- Sporothrixosis

50
Q

Mycoses: Cutaneous

A 
in and on skin
-Epidermophyton spp
-Microphyton spp
-Tricophyton spp
Tinea capitum (scalp), barberis (beard), corporis (body), unguium (nail), cruris
(Tinea... latin for worm)
51
Q

Protists

A

-Eukaryotic Cells
-most unicellular (sometimes colonial) some multicellular
-most microscopic (5um to 5mm); some macroscopic
-mostly aquatic, some marine, some moist soil, some pathogens of humans
-survival mechanism: CYST
-simplest method of grouping:
Plant like Protists: Algae
Fungus like Protists: Slime Molds
Animal like Protists: Protozoa

52
Q

Algae

A

-photosynthetic organisms
-microscopic forms are unicellular, colonial, filamentous
-macroscopic forms are colonial and multicellular
-contain chloroplasts with chlorophyll a and other pigments
-cell wall (composition varies)
-may or may not have flagella
-most are free-living in fresh and marine water- PLANKTON
-provide basis of food web in most aquatic habitats
-produce large proportion of atmospheric O2
-most are non pathogenic
Dinoflagellate can cause red tides and give off toxins that cause food poisoning

53
Q

Algae Classification

A
  • classified according to types of pigments and cell wall

- used for cosmetics, food, and medical products

54
Q

Algae of Interest to microbiologists

A
  1. Gelidium- marine red algae used to make agar
  2. Alexandrium (aka Gonyaulax)
    -dinoflagellates
    -produces saxitoxin (neurotoxin)
    -causes PSP paralytic shellfish (muscles, clams, oysters) poisoning
  3. Gambierdiscus (in Caribbean)
    -dinoflagellates
    -produces cigua toxin in game fish like grouper and red snapper
    -causes disease ciguatera
    -toxin not inactivated by cooking
  4. Pfiesteria
    -dinoflagellate
    -2 toxins: 1 waterborne, 1 airborne
    Toxin attacks immune system, higher level brain function (brain damage)
    -Life cycle: -during winter; algae eater (amoeboid shape); kleptochloroplasts
    -increased run off leads to increased fish population, in response to scent of fish feces organism changes shape, becomes “clawed”, tears fish to shreds
55
Q

Algae of interest to microbiologists: Gelidium

A

marine red algae used to make agar

56
Q

Algae of interest to microbiologists: Alexandrium (aka Gonyaulax)

A
  • dinoflagellates
  • produces saxitoxin (neurotoxin)
  • causes PSP paralytic shellfish (muscles, clams, oysters) poisoning
57
Q

Algae of interest to microbiologists: Gambierdiscus (in Caribbean)

A
  • dinoflagellate
  • produces cigua toxin in game fish like grouper and red snapper
  • causes disease ciguatera
  • toxin not inactivated by cooking
58
Q

Algae of interest to microbiologists: Pfiesteria

A

-dinoflagellate
-2 toxins: 1 Waterborne, 1 Airborne
Toxin attacks immune system, higher level brain function (brain damage)
-Life cycle: -during winter; algae eater (amoeboid shape); kleptochloroplasts
-increased run off leads to increased fish population, in response to scent of fish feces organism changes shape, becomes “clawed”, tears fish to shreds

Microbiology (20 decks)

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