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Glossary of Micro Practical 1

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Created by cadomanis

what is the size, shape and arrangement of staphylococcus?
small
circular / coccus
clustered

what is the size, shape and arrangement of Bacillus Subtilis?
small
rod shaped
isolated chains

what is the size, shape and arrangement of Escherichia Coli?
tiny
rounded rod shapes
clustered

what is the size, shape and arrangement of mycobacterium?
tiny
bacillus palisades
isolated

What is the procedure to make a simple stain?
1. create a fixed smear on a slide

2. cover the smear with methylene blue for 30-60 seconds

3. wash off the stain with distilled water

4. blot the smear with absorbent paper and let it dry





what reagents are used to make a simple stain?
methylene blue
what is the procedure for Acid-Fast staining?
1. prepare a fixed smear

2. cover the smear with carbolfuchsin for 5 min.

3. was off with distilled water

4. wash the smear with decolorizer, acid-alcohol for 1 min or until no more red color runs off

5. wash the smear with distilled water

6. counter stain the smear with methylene blue for 1 min.

7. was the smear with distilled water and blot dry











what reagents are used in acid-fast staining?
carbolfuchsin

acid-alcohol

methylene blue



what is the procedure for a structural stain of endospores?
1. make a fixed smear

2. place a piece of absorbent paper over the smear

3. cover the paper with malachite green

4. steam the slide for 5 min

5. was the smear with distilled water

6. cover the smear with safranin for 30 sec

7. was the smear with distilled water and blot dry











what reagents are used for structural stains of endospores?
malachite green
safranin
what is the procedure for a structural stain of capsules?
1. place a loopful of congo red where you will place your bacteria

2. prepare a thick smear of bacteria in the congo red and allow to dry

3. cover the smear with acid-alcohol for 15 sec

4. wash the smear with distilled water

5. cover the smear with acid fuchsin for 1 min

6. was the smear with distilled water and blot dry









what reagents are used to make structural stains of capsules?
Congo red
acid-alcohol
acid fuchsin

what is the procedure for making a structural stain for flagella?
1. cut a piece of bacterial culture from an agar plate

2. gently touch the cultured side of the agar to a slide and allow to dry

3. cover the slide with flagella mordant for 10 min

4. rinse with distilled water

5. cover the slide with carbolfuchsin for 5 min

6. rinse with distilled water and let air dry









what reagents are used in the structural staining of flagella?
mordant
carbolfuchsin
what results from streak plating?
each streaked quadrant should have less and more spread out bacteria than the area before it.
what are the benefits of growing bacteria in nutrient broths?
broth cultures provide large numbers of bacteria in a small space and are easily transported.
what is a chemically defined medium?
a medium whose exact chemical composition is known
how is it that agar stays solid during microbial growth?
few microbes can degrade agar
what is agar made of?
an extract from marine red algae
what does it mean if a broth is turbid after incubation?
growth has taken place
how does sterilization usually take place?
using an autoclave
what type of agar is used to determine if a bacteria is motile?
semisolid agar deeps that contain .5-.7% agar instead of the usual 1.5%
what is a pure culture?
one that contains a single kind of microbe
what are the three dilution methods used for the isolation of bacteria?
the streak plate

the spread plate

the pour plate



what is the streak plate technique?
a loop is used to streak a mixed sample many times over the surface of a solid culture medium in a Petri plate
what is the most common isolation technique used today?
the streak plate
how does streak plating work?
streaking the loop repeatedly over the agar surface causes the bacteria to fall off the loop one by one and ultimately be distributed over the agar surface, where each cell develops into a colony
what is the spread plate technique?
a small amount of a previously diluted specimen is spread over the surface of a solid medium using a spreading rod
what is the pour plate technique?
when a small amount of diluted sample is mixed with melted agar and poured into empty, sterile petri dishes
what is the range of colonies on a pour plate that is accurate enough to use?
between 25 and 250 colonies
how is the number of bacteria in an original sample calculated when using the pour plate method of isolation?
colony forming units per ml = # of colonies / dilution * amount plated
what is selective media?
media that contain chemicals that prevent the growth of unwanted bacteria without inhibiting the growth of the desired organism

what is enrichment media?
media that contain chemicals that enhance growth of desired bacteria. other bacteria will grow but the desired bacteria will be increased
what is differential media?
media that contain various nutrients that allow the investigator to distinguish one bacterium from another by how they metabolize or change the media

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