Microbiology Lab Midterm

Labs 1-8

Abbie condensor

concentrates light in the microscope

What is a microscope parafocal

keeps focus while switching objectives

rigid with few coils

spirillum 

flexible with numerous coils

spirochete

sexual spores

require joining of protoplasm and nuclei from two different hyphae

asexual spores

produced on modified hyphae called conidiophores or sporangiophroes 

What is the study of fungi called

mycology

What is the main difference ebetween the cell strucutre of organisms in domain Bacteria and domain Eukarya

• Domain Bacteria dont have membrne bound nucleus and organelles VS Domain Eukarya have membrne bound nucleus and organelles 

What advantages are associated with the ability to reproduce asexually as well as sexually

• ability to quickily grow population

• asexually it does not have to wait to find a mate but sexually the mate can bring diversity

• sexuall can remove mutations and errors of cells creating higher resistance and stability

What are 5 important ecological and evironmental functions of fungi

1. help with decompistion of surrounding matter

2. assists plant nutrient intake and H2O from soil

3. can break down pollutants and toxins

4. enhances soil abilities and functions as it aids health and strucutre

5. have ability to act as predators and control popualtions

What are some differences in cellular structure of blue green bacteria compared to that of other bacteria 

photosynthetic with lots of internal membranes thylakoid membranes 

How does the cell structurer of fungi differ from that of bacteria

Fungi are eukaryotic so they have membrane bound nucleus and organelles VS bacteria are prokaryotic lack nucleus membrane bound organelles

What are the five different cell groupings formed by spherical bacteria

1. coccus O

2. diplococus OO

3. Streptococcus OOOOO

4. Tetracoccus OOOO (in cube)

5. Staphylococcus OOOOOOOOOOO (clustered)

Why is the process of photosynthesis so important to maintenance of both plant and animal life on earth

Plants convert sunlight into energy for the plant it releases the byproduct O2 that is vital to all living organsims while also using our waste product CO2 in photosynthesis 

How does the cellular structure of blue green bacteria compare to that of algae

• blue green bacteria are prokaryoes lacking cell membrane bound nucleus

• algae are eukaryotes with membrane bound organelles

List five ways algae are economically and ecologically important

1. Photosynthesis

2. use CO2 in own synthesis of O2 (photosyntheis)

3. food source

4. filters H2O

5. environmental factor, sustaning habitat

List 4 protozoan pathogens and disease they cause 

1. cyclosporiasis > parasitic infection w/ cydospora

2. cryptosporidium > parasitic infection w/ cryptosporidiosis

3. amebiasis > parasitic infection w/ amebic dysentery

4. plasmodium > parasitic infection w/ malaria 

Bacteria

• Prokaryotic or eukarytoic

• Unicellular or multicellular

• photosynthetic or saprophytic &/or parasitic

• cell wall or no cell wall

prokaryotic, unicellular, photosynthetic and saprophytic, cell wall

Algae 

• Prokaryotic or eukarytoic

• Unicellular or multicellular

• photosynthetic or saprophytic &/or parasitic

• cell wall or no cell wall

eukarytoic, unicellular and multicellular, saprophytic, cell wall

Cyanobacteria

• Prokaryotic or eukarytoic

• Unicellular or multicellular

• photosynthetic or saprophytic &/or parasitic

• cell wall or no cell wall

prokaryotic, unicellular, photosynthetic, cell wall

Molds

• Prokaryotic or eukarytoic

• Unicellular or multicellular

• photosynthetic or saprophytic &/or parasitic

• cell wall or no cell wall

eukaryotic, multicellular, saprophytic, cell wall

Yeasts

• Prokaryotic or eukarytoic

• Unicellular or multicellular

• photosynthetic or saprophytic &/or parasitic

• cell wall or no cell wall

eukaryotic, unicellular, saprophytic, cell wall

Protozoa

• Prokaryotic or eukarytoic

• Unicellular or multicellular

• photosynthetic or saprophytic &/or parasitic

• cell wall or no cell wall

eukarytoic, unicellular, photosynthetic and saphrophytic, no cell wall

Heat fixation of microbial specimen

passing slide quickly over flame to set bacteria to observe and stain

Procedure of heat fixation

1. pass slide over flame 3-4 times

2. let cool then dye for observation

What are 3 reasons heat fixation is necessry

1. adheres cells to slide

2. increases dye uptake

3. kills cells/maintains shape

Why is it important to airdry your speicimen before you heat fix it 

can burst cells with H2O heating up, destorying the cells we would have observed under the microscope

What two dyes are used for negative staining and three dyes used for simple staining

• Negative: nigrosin and congo red

• Simple: safranin, methylne blue, crystal violet

What are the basic shapes of bacteira

bacillus, coccus, sprilochetes

What are two reasons for staining bacteria

• help identify shape of bacteria

• identifing shapes, strucutres, and actual different types of bacteria much easier than in transparent form

How much of a colony or culture be taken to make smear and why

a nick b/c slide can become cloudy limiting our visibilty of the bacteria

What are the steps to a gram stain

1. make a smear

2. heat fix

3. stain

   1. crystal violet (20 sec)

   2. iodine (1 min)

   3. decolorization (15 sec)

   4. counterstain w/ safranin (1 min)

4. blot dry

What color is bacteria if gram - 

red 

What are the steps to making an acid fast stain

1. smear w/ both bacteria

2. heat fix

3. stain

   1. carboyl fuschin (4 min w/ heat)

   2. acid alcohol rinse (15 sec)

   3. counterstain w/ methylne blue (1 min)

4. blot dry

What color is an acid fast + and - 

a + is magenta and - is blue 

In the gram stain what is the mordant and what is the countestain

mordant: grams iodine

counterstain: safranin

for what 2 diseases is acid fast staining an importants diagnotstic tool

TB and leprosy

What is the difference about the cell wall of an acid fast organsim describe morphological differences between acid fast positive and acid fast engative organisms

They have high lipid content (mycolic acid) 

• Acid fast + have thick cell wall (mycolic acid)and resistant to decolorization

• Acid fast - have no cell wall + no mycolic acid 

How does a negative stain differ from a simple stain

negative stain stains the background but not the cells VS simple stains do stain the cell

What two genera of bacteria commonly produce endospores

bacillus and clostridium

Under what conditions do bacteria produce endospores and what is their purpose

when they are without essentials to survive (H2O, nutrients, O2) it is a survival mechanism to keep cell inactive but alive until better conditions 

List 3 diseases that are caused by bacteria that produce endospores

botulism, tetanus, anthrax

What is the relationship between the morphological types of bacteria and gram stains reaction

see general rule on pg 44

why should only young cultures be used in gram stin

they can give innacurate results and gram variables instead of definite result

Antimicrobial agent

used to kill or inhibit growth of microorganisms

antiseptic

antimicrobials used on skin or mucous membranes

disinfectant

used to kill/inhibit microorganism on inanimate objects

chemotheraputic agent

antimicrobials taken internally to treat infections

antibiotic

chemotheraptutics that are made by microorganisms

bacteriostatic

inhibits growth of bacteria without killing

bacteriocidal

kills growth of bacteria

sterile

free of bacteria and microorganisms

What practical applications are made of our knowledge of the destructive action of radiation and chemicals on bacteria 

good resources for sterilization and general elimination/inhibiting any harmful bacteria

are all wavelengths of UV readiation equally damaging to bacterial cells

UV wavelengths will all be damaging to bacteria eventually however UV wavelengths that are shorter do much more damage because of their higher frequency

If the zone of inhibition of antibiotic A is twice as wide as that of antibiotic B does that mean A is twice as effective as B

No depends on other factos including the amount of bacteria, how fast bacteria grows, and how quickly the antibiotic diffuses

List radiation types that are germicidal

• gamma

• x rays

• beta

  • UV

What is the total maginification when using the objectives

• scanning objective

• low power

• high power

• oil immersion

• scanning: x40

• low power: x100

• high power: x400

• oil immersion: x1000

One of the major differences between a prokaryote and eukaryote

no membrane bound nucleus in prokaryotes

an example of prokaryote

cyanobacterium

streptococcus would be

chained cocci

Which is larger of the two microorganisms bacteria or cyanobacteria

cyanobacteria

The difference between a spirochete and spirillum is

one is flexible spiral bacteria and the other is rigid spiral bacteria 

A fungus that has no divisions within its hyphae is

nonseptate

A sexual spore in a zygomycota fugus is

zygospore

protozoa and algae are considered

eukaryotes 

a protein coat surrounding the cell in many ciliates, euglena and other protozoa

pellicle

amoeba move by

pseudopodia

diatoms have special covering aorund them composed of 

silica

division in protozoa have two flagella, eye spot, chloroplasts, pellicle, reservoir, and carrier out photosynthesis and/or ingests food is

euglenozoa

paramecium and other members of division are very motile how do they mvoe

cilia

brown algae is found in marine environments it is attathced to substrate by 

holdfast

agar, nori and other food products come from

red algae

Microbiological media is

a material for growing microbes

liquid solution for growing microbes is

broth

agar melts at 95-100 C but solidifies at

42-45 C

The dye used in gram stain are

crystal violet, safranin

dye used in simple stain are 

a. congo red

b. nigrosin

c. indian ink

d. methylne blue

e. all above will work

d. methylne blue

staphylococcus epidermis is

a coccus

negative stain

does not stain cells stains background

dye used in negative stain is 

nigrosin

simple stain

uuses a single basic dye

it is importnat to heat fix the cell to the slide when doing the negative stain true or false

false

Why do yu heat fix your slide

makes the cell stick to the slide, kells the cells and maintains their shape, to take dye better

why do you need to air dry you slide before you heat fix it

the cells do not burst and destory their shape

why do we want to stain our cells

difficult to see b/c translucent, to see shape, arrangement, and differentiate between types

you would predict a spore forming rodshaped bacterium such as bacillus subtilis to be gram + or -

gram +

dyes used in the gram stain are

crystal violet, safranin

organims that stained negative using acid fast stain will be stained 

blue

an acid fast stain sued to stain

a. gram -

b. gram +

c. nucleus of cell

d. genus mycobacterium

d. genus mycobacterium

example of non-ionizable radiation is

UV light

example of ionizable radiation is 

x rays

What dye is the countestain in gram stain

safranin

what is the difference in the cell wall of an acid fast bacterium and non acid fast bacterium

acid fat have thicker fatty cell wall with mycolic acid VS non-acid fast lack mycolic acid

name one of the two genera of bacteria that commonly form endospores

bacillus and clostridium 

Ionizing radiation

beta, gamma, x-rays

non-ionizing radiation

UV

comma shaped baceria

vibrio