Microbiology Lecture 1 Flashcards
1
Q
microbes
A
- minute creatures
- less than 1/2 a mm in size
- not visible to naked eye
2
Q
ubiquitous
A
they are everywhere
- microbes
- they are in air, water, soil, inside us
3
Q
normal flora
A
- under normal conditions
- found in the gastrointestinal tract, genitourinary tract, respiratory tract, skin
- made up of microbes that are found in our bodies under normal conditions
4
Q
benefits of microbes
A
- protect us from disease by suppressing growth of pathogens (normal flora)
- pathogens do not get enough nutrients bc nutrients are being used up by the normal flora
- E. coli in large intestine makes vitamin K used for blood clotting (part of normal flora)
5
Q
microbes in aquatic environments
A
- filled with unicellular algae (bottom of food chain)
- food chain ex. unicellular algae > tiny fish > large fish > sharks
- all the organisms depend on unicellular algae
6
Q
unicellular algae
A
- bottom of food chain
- live in aquatic environment
- autotrophs (use CO2 and water to make sugar and release O2 (Photosynthesis)
- 80% of O2 is from unicellular algae
7
Q
soil microbes
A
- loaded with microbes
- recycle chemical elements
- decompose dead animals and plants
- breakdown cellulose and release CO2
- broken down cellulose is used by other plants
8
Q
microbes in food
A
- used to make things like
- yogurt
- cheese
- bread
- yeast + flour = dough
9
Q
rising dough
A
- yeast breaks down sugar in dough to release CO2 -> bubbles get trapped and cause expansion
- causes dough to rise
10
Q
therapeutic substances
A
- genetic engineering is used to force E. coli to make human insulin
- utilizing microbes
11
Q
bioremediation
A
-microbe are used to clean up chemical pollutants (oil spills) in the environment
12
Q
insecticide
A
- BT toxin is sprayed on plants (utilize microbes)
- kills insects
13
Q
sewage treatment
A
breakdown organic matter to produce methane
14
Q
harmful aspects of microbes
A
- cause disease like tuberculosis & lyme disease
- cause spoilage of food products (microbes break down sugar (lactose) and release acids)
15
Q
history of microbiology
A
- 1665- Robert hooke- plant materials (leaves and stems) little boxes called cells (not microbes)
- 1673-1723- anton van leeuwenhoek observe microbes under the microscope
16
Q
Anton Van Leeuwenhoek
A
- used rain water, scraping from his teeth to observe
- he saw microbe animalcules (different shapes floating around)
- circular, rod, spiral
17
Q
spontaneous generation theory
A
- life could arise from nonliving matter
- ex. decaying meat can give birth to maggots
18
Q
Francesco Redi
A
- tried to disprove spontaneous generation theory
- he put decaying meat in open and closed jars
- the closed jars didnt have maggots while the open had maggots
- repeats experiment with fresh air
19
Q
John Needham
A
- heated broth and poured into containers -> few days later -> microbes were found in broth
- people believed the broth gave birth to the microbes but the air born microbes contaminated broth
20
Q
spallanzani
A
- poured broth and sealed the containers -> then he heat it up -> this killed all the microbes after it was sealed
- no microbes arose
21
Q
theory of biogenesis
A
- rudolph virchow
- life could arise only from pre-existing living cells
22
Q
Disproving spontaneous generation theory
A
- louis pasteur- father of microbiology
- 1861
- took a flask with a long neck and added broth -> bent the neck of the flask into an S shaped curve leaving the flask open (fresh air) -> heat broth -> microbes did not show up
- microbes got stuck in the curve of the neck like a filter
- successfully disproves the spontaneous generation theory
23
Q
louis pasteur discoveries
A
- father of microbiology due to proving the spontaneous generation theory wrong
- microbes are ubiquitous
- foundation for the aseptic procedure used in the lab to prevent contamination
- fermentation -> yeast converted sugars to alcohol and CO2 in absence of O2
- pasteurization -> beverages such as milk are heated enough to kill microbes without destroying the flavor (doesnt kill ALL microbes) -> prevents diseases from spreading from food
24
Q
germ theory of disease
A
- belief microbes could cause diseases
- once fermentation was discovered they realized microbes cause changes in the body -> disease
- 1860s- Joseph lister treated surgical wounds with disinfectant
- 1876- robert koch proved germ theory of disease
- animals were dying of disease
25
Robert Koch- Germ theory of disease
- drew blood from animals that died of disease
- isolated rod shaped bacterium (isolate #1)
- grew that bacteria in lab and obtained pure culture of bacterium
- injected bacterium into healthy animals
- healthy animals soon became sick and died
- isolated rod shaped bacteria in these animals (isolate #2)
- isolate #2 came from experimental animals while #1 came from nature
- isolates were identical proving that is was the cause of the disease
- bacterium was identified to be bacillus anthracis (anthrax)
- steps are known as Kochs postulates - identifies the determinant of a disease
26
Kochs postulates
- used to determine causative agent of mysterious infectious disease
- isolates bacterium from animals sick in nature
- injects into health animals
- compare the isolates
27
penicillin
- toxic to bacteria but not human cells
| - 1928- alexander fleming
28
naming organisms
- 1735- carolus linnaeus
- genus and species
- latin
- binomial
- describes the organism or honors a scientist
- underlined or italiced
- capitalize the genus and not the genus
29
Staphylococcus aureus
- part of the normal flora of the skin
- genus- Staphylococcus (staphylo-cluster, coccus- circular)
- species- aureus (golden brown)
- exists in golden brown circular clusters
30
Escherichia coli
- E. coli
- genus- Escherichia (honors the scientist)
- species- coli
- normal flora in large intestine
- not all E. coli is good (producing vitamins) -> some are pathogens
31
diversity of microorganisms
- bacteria- prokaryotic
- pre-nucleus- DNA is NOT surrounded by a membrane (no nucleus)
- unicellular
- heterotroph- get energy from organic molecules
- cells walls made of peptidoglycan
32
fungi
yeasts and molds
- eukaryotic
- unicellular/multicellular (most multi)
- ALL are heterotrophs
- cells walls are made of chitin
33
eukaryotic
true nucleus
34
protozoa
- eukaryotic
- unicellular
- heterotrophs
35
algae
- eukaryotic
- unicellular/multicellular
- ALL autotrophs- photosynthesize
36
virus
- acellular
- not made up of cells (no plasma membrane, no organelles, no cytoplasm)
- they do have DNA or RNA
- obligate intracellular parasites (need a host cell to reproduce)
37
helminths
- worms
- multicellular
- they are not microscopic but their eggs are
- eggs can be observed under a microscope in spit when a person is infected
38
classification of organisms
- 1969-robert whittaker classifies organisms
- 5 kingdom system
- based on:
- cell type- prokaryotic/eukaryotic
- cellular organization- unicellular/multicellular
- nutritional requirements- photosynthetic/nonphotosynthetic
39
5 kindgoms
- prokaryotae (monera)- prokaryotic ex. bacteria
- protista- protozoa ex. ameba
- fungi- yeasts and molds
- plant- ferns, trees, flowering plants
- animal- worms, insects, vertebrates
40
3 domains
- based on ribosomal RNA sequence
| - archaea, bacteria, eukarya
41
archaea
- prokaryotic
- unusual -> extreme environments
- salt lakes
- dead sea
- do not have peptidoglycan cell wall
- cell walls are made of pseudomurein
42
bacteria domain
- prokaryotic
- normal flora
- pathogens
- most organisms have peptidoglycan cell walls
43
eukarya domain
- all the eukaryotic organisms
- protozoa
- fungi
- plants
- animals
44
measurement of microbes
- units- micrometers
- 1000micrometers=1mm
- length of bacteria- 2 um to 7 um
- diameter of bacteria- .2um to 2 um
45
bright field microscope
- common
- field is bright (background)
- cells are darker than the background
- stain the cells (may cause damage)
- aka- compound microscope
- object is magnified by two separate lenses -> ocular and objective
- total magnification
- resolving power is .2um
46
total magnification
magnification by the objective lens X magnification by the ocular lens (10x)
47
resolving power
- resolution
| - clarity/sharpness of image
48
oil immersion
- improves the resolving power
- 100x lens aka oil immersion objective lens
- add a drop of oil immersion on the slide before 100x
- light bends away from the objective lens in the absence of oil immersion
- oil immersion causes most of the light to go through the objective lens
49
dark field microscope
- cells are not stained
- if you do not want the cells to be damaged use this
- field is dark but object is bright
50
Treponema pallidum
- spirochete
- causes syphilis
- destroyed by staining
- must use dark field microscope
51
phase contrast microscope
- no staining
| - used to see internal structures: organelles, endospores (bright oval structure)
52
fluorescent microscope
- UV is light is used to illuminate the object
- cells are stained with fluorescent dyes
- Auramine O is used to stain Mycobacterium tuberculosis
- cells show up as glowing yellow objects against dark background
53
electron microscope
- transmission electron microscope (TEM)
- scanning electron microscope (SEM)
- beam of electron is used in place of light
- cells are stained
54
transmission electron microscope (TEM)
- thin sections of the specimen are obtained and placed on a copper mesh grid
- magnifies object 10,000X to 100,000X
- resolving power of .0025um
- used to observe internal structures
55
scanning electron microscope (SEM)
- used to observe structures found on the surface of microbes ex. flagella
- magnifies the object 1000x to 10,000X
- resolving power or .02um
56
staining
- dyes are salts
- used for bright field microscope
- positive and negative ions: either basic or acidic
- bacterial cell is negatively charged (its attracted to positive ion) -> ionic bond is formed between the cell and the stain
- therefore basic dyes are used to stain bacterial cells
57
basic dye
positive ion has the color
- methylene blue chloride
- used to stain the cell
58
acidic dye
- negative ion has the color
- sodium eosinate
- negative cells are repelled by negative ions -> this stains the background
59
nigrosin
- acidic dye that is used
- negative ion has the color
- negative cell repels negative ion
- background is black and cells are bright (similar to dark field)
- negative staining
60
simple staining
-basic dye is used to stain the cell to determine the shape and arrangement of cells
61
gram staining
- differential staining technique that uses a primary stain and secondary counterstain to distinguish gram + or - bacteria
- places bacteria into 2 groups
- gram positive and negative
- most important staining bc it helps us identify unknown bacteria
- based on the cell wall structure of the bacterial cell
62
negative staining
- uses an acidic dye
- negative ion has the color
- when an negative cell interacts with the acidic dye the background is dyed
- improves the contrast -> we can see the arrangement and shape of the cells
63
gram positive
- do one set a biochemical tests on that bacteria to figure out the genus and species
- show up purple
- thick cell walls (peptidoglycan) -> helps hold on to the primary stain (crystal violet)
64
gram negative
- do completely different set of chemical tests to identify the bacteria
- show up pink
- thin cell wall (only 1 or 2 layers of peptidoglycan)
- they have a outer membrane made up of lipids which is damaged by the alcohol used during gram staining -> causes primary stain to leak out and become colorless during gram staining acetone-alcohol step
65
gram staining reagent
- crystal violet- primary stain
- iodine- mordant
- alcohol-acetone- decolorizer
- safranin- counterstain
66
steps of gram staining
1. first add crystal violet as a primary stain to bacterial specimen -> this stains both + and - cells purple or blue
2. iodine, a mordant (strengthens the ionic bond btwn the bacterial cell and crystal violet), makes dye less soluble so it adheres to cell walls -> both + or - remain purple or blue
3. acetone-alcohol (decolorizer) washed stain away from gram neg -> gram - cells become colorless while gram + remain purple or blue (differentiation step)
4. Safranin (basic counterstain) allows dye adherance to gram-negative cells -> gram - cells turn pink while gram + remain purple or blue
67
mordant
- strengthens the ionic bond between the bacterial cell and crystal violet
- iodine
68
acid fast staining
- differential staining
- two genera are acid fast:
- myobacterium and nocardia
- they have waxy substance known as mycolic acid (complex lipid) in their cell walls
- acid fast staining is used to identify these two bacterium (used for tuberculosis)
69
reagents for acid fast staining
- carbolfuchsin- primary stain
- acid-alcohol- decolorizer
- methylene blue- counterstain
- acid-fast= red
- nonacid-fast=blue
- both start out red due to primary stain -> decolorizer -> nonacid-fast loses color -> counterstain -> nonacid-fast turns blue -> acid-fast stays red
70
capsule staining
- capsule is a gelatinous substance found around the cell wall
- cannot be stained
- not all bacteria has capsule
- stain the background using nigrosin
- stain the cell body with crystal violet
- background is black
- capsule shows up as a clear ring around the stained cell
- capsule is not being stained
71
endospores
- 2 genera of bacteria that make endospores are bacillus and clostridium
- endospores are resistant to hostile environmental conditions (heat, UV light, disinfectant, desiccation)
- dormant stage of the cell
- endospores are formed within the vegetative cell (active cell)
- once formation is complete, endospores are released into environment
- vegetative cells make endospores when the environment lacks nutrients
72
endospore staining
- malachite green- primary stain
- water- decolorizer
- safranin- counterstain
- endospores=green
- vegetative cells=pink
- both vegetative and endospores pick up primary stain -> both turn green -> water decolorizes vegetative cells -> vegetative cells pick up counterstain (safranin) and turn pink -> endospores remain green
73
eukaryotic cell
-true nucleus
74
organelle
specialized structure with specific function
75
cilia
filamentous structures on the surface of the cell
- short and numerous
- on some eukaryotes
- if it has cilia there are many on the surface
- help cell move
76
flagella
- filamentous structures
- long and few
- on some eukaryotes
- if it does have it is usually one or two
- help cell move
77
cell walls
- plant cells have cullulose cell wall
- fungi have chitin cell wall
- animal cells have no cell wall
78
glycocalyx
- sugar coat
- made up of cardohydrates
- found on surface of plasma membrane
- protects the cell
- animal cells have this
79
plasma membrane
- proteins, lipids and carbohydrates
| - encloses cytoplasm
80
cytoplasm
-has cytoskeleton
81
cytoskeleton
- made up of minute filaments that form a network within the cytoplasm
- microfilaments
- microtubules
- intermediate filaments
- involved in cytoplasmic streaming- cytoplasm circulates within the cell such that the nutrients are distributed throughout the cell
82
cytoplasmic streaming
cytoplasm circulates within the cell such that the nutrients are distributed throughout the cell
83
DNA
- within the nucleus
- chromatin is made up of DNA
- packaged into nucleosomes
- DNA is surrounded by the nuclear envelope (membrane)
84
nuclear pores
- molecules move in and out of the nucleus through these
- DNA must be packaged into nucleosomes in order to move through
- holes in the nuclear envelope
85
nucleolus
-ribosomal RNA is being synthesized here
86
histones
- proteins
- segments of DNA are wrapped around histone proteins
- histone + DNA = nucleosome
87
nucleosomes
- segments of DNA are wrapped around histone proteins
- these are packages
- move through the nuclear pores
- DNA + histone = nucleosome
88
ER
- made up of flat membrane sacs
- make up network throughout cytoplasm
- rough- ribosomes are attached to the surface & proteins are synthesized
- smooth- no ribosomes attached- lipids are being synthesized
89
ribosomes
- free in the cytoplasm
- show up as dots in a micrograph
- attached to rough ER
- made up of 2 subunits
- each subunit is made up of proteins and ribosomal RNA
- eukaryotic cells has 80s ribosome
- larger and denser than prokaryotic ribosomes (which is 70s)
90
golgi complex
- made up of flat membrane sacs (4-6)
- proteins and lipids made in the ER are transported into the golgi complex
- modifies molecules
- transports molecules to other parts of the cell once they are modified
- ex. lipid is added to protein to make lipoprotein
91
mitochondria
- cellular respiration
- makes ATP
- power house of the cell
- two membranes: outer (smooth) inner (folded)
- innermost (matrix)- has enzymes needed for kreb cycle, 70S ribosomes, & has DNA*
- folds: cristae
92
cholorplast
- found in plant cells
- specialize in carrying out photosynthesis
- has chlorophyll- green pigment
- 2 membranes
- thylakoids- membrane sacs that have the chlorophyll
- has DNA and 70S ribosomes
93
lysosomes
- membrane bound vesicles
- made up of membranes
- membrane bags filled with digestive enzymes
- white blood cells have a large # of lysosomes
- specialize in destroying microbes
94
vacuole
- cavity surrounded by a membrane
- plant cells have large water vacuole
- when they are filled with water it makes the leaves and stems more rigid
95
centriole
- cylindrical structure
- usually cell has 2
- made up of proteins
- associated with cell division
96
helminths
- worms
- multicellular
- eukaryotic
- animal kingdom
- do not have a well developed nervous system or digestive system
- they do have a complex reproductive system
- platyhelminthes (flatworms) and nematodes (round worms)
97
platyhelminthes
- trematodes (flukes)
| - cestodes (tapeworms)
98
trematodes
- flukes
- flat leaf like body
- hermaphroditic- both male and female reproductive organs (testes and ovaries)
- intermediate host- immature worm (larvae) lives here, asexual reproduction takes place here
- definitive host- mature worm (adult) lives here, sexual reproduction takes place here
99
paragoniumus westermani
- lung fluke
- bronchioles of infected humans and other animals
- 12mm long
- lives for 4-5 years
- chest pain, cough
- treated with praziquantel
100
life cycle of paragoniumus westermani (lung fluke)
- adult worm lives in lungs of infected humans (definitive host)
- eggs are released in the lungs
- eggs end up in the suptum and spit
- if it is swallowed the eggs end up in the feces
- if the eggs then end up in the water larvae will penetrate into a snail (intermediate host)
- larvae undergo asexual reproduction within the snail
- larvae exit the snail and enter creyfish (intermediate host) -> forms a cyst
- cyst has the resting baby worm -> if people eat this contaminated creyfish it will go into the human digestive tract and lungs
- cycle repeats
101
cestodes
- intestinal parasites
- tape worms
- head- scolex
- scolex- has hooks an suckers -> help attachment to the host
- segmented body
- segments- proglottids
- hermaphroditic
102
taenia saginata
- beef tapeworm
- can be as long as 18ft
- can live for 25 years
- adult- lives in intestinal tract of human (definitive host)
- eggs are released in feces
- cattle- ingest (intermediate host)
- larvae- cysts in the muscles (cysticerci) of cattle
- transmitted to humans when we eat undercooked contaminated beef
- intestinal tract- scolex comes out- develops into an adult worm
- repeat
- diagnosis- presence of eggs in feces
- symptoms- not much, abdominal discomfort
- treated with niclosamide
103
taenia solium
- tapeworm
- adult- lives in infected humans (definitive host)
- eggs- found in feces
- ingested by pigs (intermediate host)
- larvae- cysts in the pigs muscles
- undercooked contaminated pork spreads to humans
- more dangerous bc humans can also become intermediate hosts -> *EGGS AND LARVAE ARE INFECTIOUS
- larvae cysts can form in humans in muscles, brain -> neurocysticercosis
104
neurocysticercosis
- swiss cheese brain
- holes in the brain
- when taenia solium eggs develop into larvae and form cysts in the brain
- symptoms- headaches, convulsions, coma, death
- can occur with poor sanitary practices
- common in mexico, south america
105
echinococcus granulosus
- tapeworm
- definitive host- dogs, coyotes
- eggs are released in feces
- can move to humans (or other animals) due to poor sanitary practices (intermediate host)
- larvae forms cysts in liver or lungs
- cysts are known as *hydatid cysts
- humans are a dead end to the life cycle of the worm -> humans are not eaten by other organisms (top of food chain) -> worm stays within human
- common in sheep herding population
106
nematodes
- roundworms
| - dioecious- male and female worms
107
enterobious vermicularis
- pinworm
- nematode
- roundworm
- lives in intestinal tract of humans
- female worm migrates to anus and releases eggs in perianal area
- itching in the area
- eggs can end up in sheets, clothing, air -> spreads
- treated with mebendazole
108
ascaris lumbricoides
- nematode, roundworm
- in small intestine
- feed on semidigested food
- eggs are released in feces
- larvae come out of eggs in intestinal tract and migrate to the lungs
- if there are too many larvae in the lungs they move back to the intestinal tract and become adult worms
- causes obstruction of the intestinal tract
109
necator americanus
- lives in intestinal tract
- eggs are released in feces
- eggs are not infectious
- larvae come out in the soil
- larvae penetrate the skin (bottom of someones foot) and go into the intestinal tract
- attaches to the intestinal wall -> drink blood
- causes anemia
- prevented by wearing shoes
- common in south east
110
trichinella spiralis
- undercooked encysted pork
- larvae come out in the intestinal tract when ingested
- female releases larvae -> worms dont release eggs they release larvae!
- larvae form cysts in the diaphragm muscles -> interferes with breathing
- pigs- get infested by eating contaminated pork or garbage
111
protozoa
- unicellular- eukaryotic
- live in soil, water, within the bodies of humans and animals
- pathogenic protozoa exist in two stages
- trophozoites- metabolically active, produce, motile, inside the host
- cyst- metabolically inactive, dormant, outside the host
112
entamoeba histolytica
- pseudopods
- ameba
- lives in intestinal tract
- cysts are released in the feces
- asymptomatic in the people who have cysts
- if the cysts are ingested trophozoites will be present in intestinal tract
- feed on cells lining the intestinal tract, red blood cells
- dysentery- bloody diarrhea
113
pseudopods
- when the plasma membrane folds outward and make a finger like projection
- ameba uses this to crawl
- "fake feet"
114
Giardia lamblia
- flagella
- tear drop shape
- 2 nuclei
- lives in intestinal tract- asymptomatic carriers
- cysts are released in the feces
- flagella in the cyst is inside the cell
- cysts are transfers through contaminated food and water
- when its ingested the trophozoites attach themselves to intestinal wall
- abdominal pain, diarrhea, **weight loss
- metronidazole- treatment drug
- common for wilderness water
115
balantidium coli
- cilia for movement
- paramecium
- 2 nuclei
1. macronucleus- controls protein synthesis
2. micronucleus- transmits genetic information
- cysts are transmitted in contaminated food or water
- trophozoites infect when they are ingested
- causes dysentery
116
Paramecium
- nonpathogenic
- protozoa
- has cilia
- macronucleus
- micronucleus (not visable)
117
hemoflagellates
- long, slender body
- undulating (wavy) membrane
- flagellum
- one nucleus
- no cyst phase only trophozoite
- ex. trypanoasoma gambiense
- causes african sleeping sickness
- transmitted by tsetse fly
- grows in bloodstream
- causes damage to the nervous system
- drowsiness, coma, death
118
trypanosoma cruzi
- hemoflagellate
- transmitted by kissing bug
- bugs live in the crack of mud huts
- mexico, south america
- damages the nerves
- grows in the blood stream
- causes chagas disease
- causes mega colon, ega esophagus -> constipation
- flagellum
- blue dot on one end -> mitochondrial DNA
119
Plasmodium
- pathogenic protozoa
- causes malaria
- transmitted by mosquito
- causes chills, fever, vomiting
- complex lifecycle
- chloroquine- treatment
- sexual reproduction takes place in mosquito- definitive host
- humans- intermediate host (asexual reproduction)
- life cycle:
1. sporozoite stage in salivary gland of the mosquito
2. sporozoites are released into the blood of person that is bit -> end up in liver
3. reproduce and become merozoites -> penetrate the RBC
3. ring stage grows and reproduces in RBC -> produces merozoites
4. RBC breaks down and merozoites are released in blood -> infect other RBC -> some merozoites differentiate into gametocytes (female and male)
5. when another mosquito bites this person the mosquito picks up the gametocytes
6. gametocyte goes into intentional tract of mosquito -> unite and form a zygote
7. zygote differentiates into sporozoite -> sporozoite migrate to salivary glands of mosquito
8. repeat
120
mycology
- study of fungi
| - myo- fungi
121
fungi
- heterotrophs- need organic molecules for energy
- absorb nutrients
- make asexual spores
- sexually reproduce
- 2 types: yeast and molds
122
yeast
- unicellular
- oval or circular in shape
- many reproduce by budding
- sometimes the buds fail to separate from the parent -> pseudohyphae are formed
- Candida albicans make pseudohyphae (part of the normal flora of intestinal tract of humans)
123
molds
- multicellular
- filamentous
- filaments are called hyphae
- fragments of hypha can grow into a fungus
124
hyphae
two types:
- septate hyphae- segmented by cross walls
- coenocytic hyphae- no segmentation
125
dimorphic fungi
- grow mold-like @ 25C outside the body
| - grow yeast-like @ 37C inside the body
126
arthrospores
- septate hyphae becomes fragmented into single cells
- have thick cell walls
- Coccidioidea immitis makes arthrospores
127
sporangiophore
- circular
- enclosed in a sac (sporangium)
- sac bursts and they are all released
- Rhizopus makes sporangiophores
128
Conidiophore
- produced by penicillium
- formed in circular chains of conidia
- not enclosed in a sac
129
sexual reproduction of reproduction
- two different strains (subspecies) need to be in the same area
- + and - -> ex. Rhizopus + and Rhizopus - can mate
- + strain makes pheromones- proteins while - doesnt
- attract negative strain with pheromones- mate -> negative strain grows towards the + due to pheromones
- + and - fuse to make zygote
- zygote differentiates into a sexual spore
- depends on environmental conditions -> fungi makes sexual spores during nutrient depletion
- if the environment has nutrients they just make asexual spores
130
3 groups of fungi
- based on sexual spores
| - zygomycota
131
zygomycota
- make asexual spores -> sporangiospores
- also make sexual spores -> zygospores
- they have coenocytic hyphae (not segmented)
- ex. rhizopus
132
life cycle of rhizopus
-zygomycota
Asexual Reproduction
1. fungus grows and produced asexual spores (sporangiospores) in a sac (sporangium)
2. sac bursts and the sporangiospores are released
3. if sporangiospores end up in an environment that has nutrients they germinate -> grow into fungi
Sexual Reproduction
1. + and - strains come together -> zygote -> zygospore
2. if zygospore ends up in an environment that has nutrients it will germinate -> fungus
133
Ascomycota
- some molds and some yeasts
- molds- septate hyphae
- molds produce asexual spore- conidiospores
- yeats reproduce by budding
- both yeast and molds produce sexual spores- ascopspores
- ex. Penicillium
134
life cycle of penicillium
Asexual Reproduction
1. Produce conidiophore (asexual)
2. conidiophore released
3. if there are nutirents they germinate -> fungi
Sexual reproduction
1. + and - strains come together and from and zygote
2. zygote germinates into ascospores
3. ascospores are enclose in a sac (ascus)
4. sac bursts and ascospores are released
5. if there are nutrients they will germinate into fungus
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basidiomycota
- mushrooms
- septate hyphae
- asexual reproduce by fragmentation of hyphae
- fungi produce sexual spores- basidiospores
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life cycle of basidiomycota
Asexual Reproduction
1. fungus grows
2. piece of hyphae ends up in an environment with nutrients -> becomes fungus
Sexual Reproduction
1. + and - strains come together -> zygote
2. zygote grows into fruiting structure -> mushroom
3. basidiospores are formed and released
4. if there are nutrients the basidiospores will germinate -> fungi
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Mycoses
- fungal disease
- systemic mycoses- deep within the body
- caused by inhaling fungal spores
- starts in the lungs and spreads
- ex. histoplasmosis, coccidioidomycosis
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histoplasmosis
- minor respiratory infection
- if immune system is weak- spreads to liver, spleen bone marrow
- a type of systemic mycoses
- caused by histoplasma capsulatum
- a dimorphic fungus
- it produced conidiospore
- found in soil enriched with bird droppings
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coccidioidomycosis
- systemic mycoses
- caused by coccidiodes immitis
- arthrospores found in soil (southwest) cause this
- when it is inhaled it can be grow in the lungs
- cough, chest pain
- treated by amphotericin B
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cutaneous mycosis
- -affects the hair, nail, skin
- ringworm, tineas
- caused by the fungi- dermatophytes
- produce keratinase- breaks down keratin
- tinea pedia- atheletes foot:
- caused by trichophyton rubrum- itching, scaling skin
- spread by direct contact, shower room floors
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opportunistic mycosis
- ex. candidiasis
- caused by candida albicans
- part of the normal flora
- if your immune system is weak -> can cause thrush
- thrush- candida infection of the oral cavity
- common in people with AIDS, newborns
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amanita phalloides
- mushroom
- called death angel
- produces a neurotoxin
- causes hallucinations
- causes damage of the liver
- causes death within a week due to liver damage
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calviceps purpurea
- grows on grains- like rye
- a mold
- produces a toxin called ergot
- causes ergotism when ingested
- causes hallucinations
- causes constriction of the capillaries -> leads to gangrene
- common in the middle ages due to eating contaminated food
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dinoflagellates
- algae
- live in aquatic environments
- have two flagellum
- aka plankton- free floating
- many different species
- ex. Alexandrium- produces a neurotoxin
- mollusks (clams) eat dinoflagellates -> toxin is concentrated in the clams -> if people eat the clams they will get paralytic shellfish poisoning
- symptoms- numbness of mouth and lips (not serious)
- neurotoxin is heat stable (not destroyed by heat)
- condition is prevented by not collecting clams during red tide
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algae
- carryout photosynthesis
- eukaryotic
- live in aquatic environments
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diatoms
- algae
- photosynthesis
- in ponds, lakes, oceans
- common
- cell walls made up of silica
- bottom of food chain
