Lab exam 2 Flashcards
Special types of cultured media are used for what?
Used to detect or isolate particular organisms
- T or F, Culture media can be liquid or solid?
- liquid media is called what? Solid media?
- True
- Liquid media = broth media
solid media = broth media w agar
*Liquefies at temperatures above 95°C
* Solidifies at 45°C
* Generally not metabolized,
agar
what media contains compounds that selectively inhibit growth of some microbes but not others?
selective media
Contains substance that allows
distinguishing of colonies of
different microbes on the same
plate
Differential medium
T/F Some media have both selective and
differential characteristics
TRUE
2 examples of differential media
- Blood agar
-MacConkey agar
When grown on solid media, cells
form what?
Isolated masses (colonies).
What is colony morphology used for?
- to identify microorganisms
- to distinguishes cultures (pure, contaminated, or mixed)
Q: Amoeba, Trypanosoma, Paramecium, and Euglena are all types of what?
A: Protozoa.
What is the formula for pfu/ml
PFU/ml=
Numberofplaques×dilutionfactor
————————————————–
volume of phage saple in mL
Name examples of an aerobe, anaerobe, and a facultative anaerobe.
Aerobe: Bacillus subtilis
Anaerobe: Clostridium sporogenes
Facultative anaerobe: Escherichia coli
What is a countable plate for bacteriophage plaques?
A plate with 25-250 plaques.
What is an anaerobe?
An organism that does not require oxygen for growth and may even die in its presence.
Q: What is the phylum for Amoeba? Trypanosoma?
Paramecium?
Euglena?
A: Amoebozoa (sarcodina)
Euglenozoa
Ciliophora
Euglenozoa
Q: Identify the domain of Anabaena and its notable feature.
A: Domain Bacteria - Cyanobacteria with heterocysts (used for nitrogen fixation).
Q: What is the function of heterocysts in Anabaena (Cyanobacteria)?
A: specialized cells used for nitrogen fixation, allowing Anabaena to convert atmospheric nitrogen into a usable form.
Q: Place Saccharomyces, Penicillium, Rhizopus, Morchella, and “mushroom” in their proper phyla (Ascomycota, Basidiomycota, Zygomycota).
Saccharomyces - Ascomycota
Penicillium - Ascomycota
Rhizopus - Zygomycota
Morchella - Ascomycota
“Mushroom” - Basidiomycota
What is a GasPak jar.
A sealed jar used to create an anaerobic environment for culturing bacteria.
Q: What is the process called when Saccharomyces reproduces asexually?
A: Budding. (forming four haploid zygotes.)
Q: Name the three types of lichen growth forms.
A: Crustose, Foliose, Fruticose.
Q: What two organisms form a lichen?
A: A fungus and an alga (or cyanobacterium).
Q: What is a slide culture used for?
A: Observing the growth and structure of fungi.
What is the reaction used in a Gas Pak to remove O₂, and what is the catalyst?
Hydrogen combines with oxygen to form water. The catalyst is palladium.
Q: What stain is commonly used on molds?
A: Lactophenol cotton blue.
What is the name of the medium used in the enrichment step?
Thioglycolate broth.
What is the purpose of the enrichment step?
promote the growth of anaerobic bacteria while suppressing others.
Where are paramecium found?
Fresh water and stagnant pools
What is the purpose of a selective medium?
allow the growth of specific microorganisms while inhibiting others.
What is the length of paramecium?
300 µm
Q: Identify sexual and asexual reproductive structures of fungi.
A: Sexual: Zygospores, Ascospores
Asexual: Conidiospores, Sporangiospores
Q: What is the sexual spore of Zygomycota, and how is it formed?
A: Zygospore; forms from mating type fusion, dark and rough.
Q: How does Zygomycota reproduce asexually?
A: By round sporangia containing sporangiospores.
Q: Describe Rhizopus reproduction.
A: Forms zygospores sexually and sporangia for asexual spores.
Q: What is Rhizopus commonly known as?
Q: Where is Rhizopus commonly found?
Q: How does Rhizopus reproduce?
Q: What are rhizoids in Rhizopus?
A: Black bread mold.
A: Growing on bread.
A: Both sexually and asexually.
A: Root-like structures that attach to food surfaces.
How is the shape of Paramecia maintained?
stiff, but elastic pellicle
Q: Where are ascospores produced in Ascomycota?
A: In an ascus, which is round or elongated.
How do Paramecia move?
by tiny cilia that cover the pellicle
Q: How many spores are in an ascus, and how do they form?
A: Eight spores; from meiosis (four) and mitosis.
What type of feeders are Paramecia?
They are filter-feeders.
Q: What unique structure does Sordaria produce?
A: Perithecium, which contains and releases ascospores.
Q: What is Morchella commonly known as?
Q: Are Morchella edible, and in which cuisine are they prized?
Q: When is Morchella in season, and why are they expensive?
A: True morels.
A: Yes, they are prized in French cuisine.
A: In the spring; they do not store or transport well.
What is the function of the oral groove in Paramecia?
forms a pocket that acts as a scoop to gather food
Q: How does Saccharomyces reproduce asexually?
A: By budding.
Q: What is Saccharomyces cerevisiae commonly known as?
Q: How does Saccharomyces cerevisiae reproduce sexually?
Q: What is the asexual reproduction method of Saccharomyces cerevisiae?
A: Baker’s yeast or brewer’s yeast.
A: By forming four haploid zygotes.
A: Budding
What are cyanobacteria commonly called?
Blue-green algae
Q: Name the three main lichen growth forms.
Q: What is litmus, and its relation to lichens?
Q: What does the color of litmus indicate?
A: Foliose (leaf-like), Fruticose (branch-like), Crustose (flat).
A: A pH indicator made from lichen pigments.
A: turns red in acid, blue in alkaline.
Q: What is Penicillium known for, and how does it reproduce?
A: Produces penicillin and is familiar blue-green kitchen mold;
reproduces by asexual spores called conidiospores on conidiophores.
Q: Describe Penicillium conidiophores.
A: Stem-like, branches with phialides producing spore chains.
Q: How are basidiospores formed?
A: In a basidium, after sexual fusion and meiosis.
Q: Name the 4 main mushroom parts and functions.
A: Cap: Produces spores.
Stipe: Supports cap.
Annulus: Collar under cap.
Gills: Produce basidiospores.
Q: Where does most of the mushroom fungus grow?
Q: What is the ploidy of mycelium from germinated spores?
Q: What forms after the fusion of compatible mating types in mushroom fungus?
A: As underground mycelium.
A: Haploid.
A: Diploid mycelium with dikaryotic cells (separate haploid nuclei).
Q: What triggers mushroom formation?
A: Favorable conditions, like cool spring rains
Q: What is the movement structure of Amoeba proteus?
Q: Where is Amoeba proteus commonly found?
Q: How does Amoeba proteus obtain food?
A: Pseudopodia (extensions formed by cytoplasm flow).
A: In freshwater.
A: Engulfs algae and smaller protozoans.
Are cyanobacteria true algae
No, they are bacteria, not true algae
What are Anabaena?
cyanobacteria that photosynthesize and can fix nitrogen
How is nitrogen fixation accomplished in Anabaena?
through heterocysts
What is a practical use for some species of Anabaena?
used to replenish nitrogen in rice paddies
Why can some species of Anabaena be harmful
can produce toxins that are harmful to local wildlife
(word bank: anoxic, obligate anaerobes, aerotolerant, obligate aerobes, microaerophiles, facultative anaerobes)
Obligate _________: absolutely require oxygen
– grow at full O2 tension (~21%) and respire O2
___________ anaerobes: able to grow with or without oxygen
– grow via fermentation or anaerobic respiration when oxygen is
NOT available
___________ anaerobes: can’t use oxygen and most are harmed by it
_____________: can tolerate but can’t use oxygen
_________________:
can use O2 only at levels reduced from that in air (microoxic) due to limited respiration or oxygen sensitivity
________ (oxygen free) habitats: mud, bogs, marshes, animal intestines, other diverse habitats
Obligate aerobes
Facultative anaerobes
Obligate anaerobes
Aerotolerant
Microaerophiles
Anoxic
Why is oxygen toxic?
forms toxic byproducts inside phagolysosome in phagocytes. (superoxide anion, hydrogen peroxide, peroxide anion, hydroxyl radical)
What are the toxic forms of Oxygen
______________ catalyzes this rxn O2 + O2 +2H+ —–> H2O2 + O2
___________ converts hydrogen peroxide to water and oxyegn
H2O2+2H+ —–> 2H2O
Superoxide dismutase
Catalase
Peroxidase
Q: What type of organism is Euglena and how does it move?
Q: Can Euglena be autotrophic, heterotrophic, or both?
Q: What is the purpose of the “eyespot” in Euglena?
Q: What is the size range of Euglena gracilis?
A: A single-celled organism; moves by means of a terminal flagellum.
A: Both; it can photosynthesize or absorb soluble nutrients.
A: photosensitive; steers the organism toward light for photosynthesis.
A: 30-50 µm in length
