question
True or False:
Most bacteria species are not harmful and they do preform useful and indispensable functions for life
Most bacteria species are not harmful and they do preform useful and indispensable functions for life
answer
True
question
What's the purpose of agar?
answer
It's a good solidifying agent since it has a high melting point (100 C) and low solidifying point (~45 C)
question
True or False:
Bacteria is everywhere and makes it hard to have sterilized equipments and media
Bacteria is everywhere and makes it hard to have sterilized equipments and media
answer
True
question
What's the correct way to label a plate?
answer
name
date
sample
procedure if relevant
date
sample
procedure if relevant
question
Why do we invert plates?
answer
-To prevent condensation on bacterial colonies
-water will provide mobility to bacteria and prevent them from forming colonies
-water will provide mobility to bacteria and prevent them from forming colonies
question
Why do the samples vary in numbers of colonies from the Ubiquity of Bacteria lab?
answer
There are different colonies growing depending on the sample source
question
Will every microbes present in a sample grow and form colony?
answer
No, some cannot grow because the environment might not be right (oxygen level, nutrients, ect.)
question
What factors influence growth of bacteria?
answer
The amount of nutrients on media, space,
question
How to carry microscopes correctly?
answer
-Carry it upright
-Don't rest it on body while walking
-Don't bump it into locker and lab bench
-Don't rest it on body while walking
-Don't bump it into locker and lab bench
question
Ocular lenses (eye piece) magnify objects ___
answer
10X
question
Objective lenses magnify objections ___ (4)
answer
4X, 10X, 40X, and 100X
question
To calculate the total magnification...
answer
ocular x objective
question
stage adjustment knobs are used to....
answer
adjust the position of the slide on the stage
question
iris diaphragm
answer
adjusts the amount of light
question
coarse focus knob
answer
focus image in 4X or 10X objective lenses
question
fine focus knob
answer
minor focusing adjustments for 40X and 100X only
question
lamp brightness control dial
answer
use to adjust microscope light
question
width of pointer in 10X objective
answer
25 um
question
width of pointer in 40X objective
answer
6 um
question
width of pointer in 100X objective
answer
2.5 um
question
1 um = ___ m = __ inches
answer
10^-6 m
1/256000 inches
1/256000 inches
question
Protozoa size
answer
20 - 100 um
question
Yeast size
answer
4 - 10 um
question
Bacteria
answer
1 um
question
Virus
answer
0.1 um (too small to be seen with light microscope)
question
How to use Darkfield
answer
-open iris diaphragm completely or else dark field will block all light, giving you a dark field (haha funny joke)
question
Dark field does NOT work in ____ objective
answer
100X
question
Wet mounts can be used for (5)
answer
-determining size
-morphology
-grouping
-motility
-general type and other characteristics
-morphology
-grouping
-motility
-general type and other characteristics
question
How to do a wet mount
answer
add drop of liquid and put on cover slide
question
Brownian motion
answer
motion due to atoms bombardment
looks like random vibrations
looks like random vibrations
question
Motility
answer
directional movement of individual cells
"swimming"
"swimming"
question
What magnification should the lenses be for safe storage?
answer
4X
question
Aseptic technique (2 parts)
answer
-anything that will come into contact with culture need to be sterilized
-need to be sterilized before the object is set down on the counter or for disposal
-need to be sterilized before the object is set down on the counter or for disposal
question
Where is the hottest part of the flame?
answer
Near the tip of the flame
question
Why should you not touch the glass when taking a loopful of bacteria out from a tube?
answer
The loopful will be released to the side of the glass
question
Why should you wait until the loop is fully cool until you touch broth or agar?
answer
-To avoid killing bacteria and creating aerosols (easily inhaled droplets that contain bacteria)
question
Why is one end of the pipette is plugged with cotton?
answer
To filter incoming air and to prevent material from floating to the top
question
Green pipet aid are used for ____ and ___ mL
answer
5 and 10 mL
question
True or False
You can touch the sterilized pipet to the side of the glass of the tube.
You can touch the sterilized pipet to the side of the glass of the tube.
answer
False: anything that touches the pipet (except broth) will result in contamination
question
True or False
Pipet must be place into the waste container directly after touching bacteria. (You can't place it on the counter)
Pipet must be place into the waste container directly after touching bacteria. (You can't place it on the counter)
answer
True
question
True or False
Cloudiness = turbidity = bacterial growth
Cloudiness = turbidity = bacterial growth
answer
True
question
Why do we use stains?
answer
To make their shape and groupings more visible
(colorless bacteria are hard to see)
(colorless bacteria are hard to see)
question
True or False
Staining kills bacteria
Staining kills bacteria
answer
True
So we don't need to boil slides before washing or discarding
So we don't need to boil slides before washing or discarding
question
Staph. epidermis is a __ shaped bacterium
answer
spherical /coccus
question
Citrobacter Freundii is a ___ shaped bacteria
answer
rod
question
Spirillum voltuans is a __ shaped bacteria with distinctive ___
answer
spiral shaped
volutin granules (metachromatic)
volutin granules (metachromatic)
question
How to make a stain from solid sample?
answer
-add loopful of water
-use sterilized loop to add bacteria
-spread to make a turbid circle
-use sterilized loop to add bacteria
-spread to make a turbid circle
question
Why do you only need a very small amount of culture for staining?
answer
-Harder to distinguish morphology
-cannot stain uniformly with thick smear
-cannot stain uniformly with thick smear
question
How to make stain from broth culture?
answer
-transfer loopful of bacteria with sterilized loop onto slide
question
True or False:
You should spread the bacteria around on the slide if you use a broth culture.
You should spread the bacteria around on the slide if you use a broth culture.
answer
False!!
Do NOT spread the bacteria or add water since broth culture are already diluted
Do NOT spread the bacteria or add water since broth culture are already diluted
question
What's the purpose of heat fix?
answer
Make bacteria stick to the slide (or else it will easily slide off)
question
What dye should you use to see the volutin granules?
answer
methylene blue
question
Basic dyes carry __ charge so they __ negative compounds on cell surface.
answer
positive, attracted
question
Acidic dyes carry __ charge so they __ negative compounds on cell surface
answer
negative, repel
question
Why should you dry the slide completely before doing oil immersion?
answer
Water and oil don't mix, will distort image
question
Resolution
answer
ability to distinguish two pints as separate
question
True or False
Humans have resolving power of 0.2mm
Humans have resolving power of 0.2mm
answer
True
Anything that's 0.2mm or more apart will be seen as separate
Anything that's 0.2mm or more apart will be seen as separate
question
Light microscope has resolving power of ___
answer
0.2 um
question
True or False
Cover slides are only used for wet mount.
Cover slides are only used for wet mount.
answer
True
question
True or False
It is critical to keep oil from other lenses that are not 100X
It is critical to keep oil from other lenses that are not 100X
answer
True
question
Gram stain is an example of ___ stain
answer
differential
question
Staph, epidermis is a Gram __ __ (shape and class-action)
answer
Gram positive cocus (purple)
question
Citrobacter freundii is a Gram ___)
answer
Gram negative rod (pink)
question
Gram stain procedure
answer
crystal violet: 30 - 60s
iodine 30 - 60s: complexes crystal violet
decolorizer: 20 - 30 s
safarin 30 -60 s
iodine 30 - 60s: complexes crystal violet
decolorizer: 20 - 30 s
safarin 30 -60 s
question
True or False
Both Gram positive and Gram negative bacteria will look purple after it added crystal violet and after iodine
Both Gram positive and Gram negative bacteria will look purple after it added crystal violet and after iodine
answer
True
question
True of False
If done correctly, Gram negative should be colorless after decolorizer
If done correctly, Gram negative should be colorless after decolorizer
answer
True
question
How can both Gram negative and Gram positive be purple or both be colorless after decolorizer?
answer
Both purple: not enough time for decolorizer
Both pink: too long with decolorizer
Both pink: too long with decolorizer
question
True or False
Gram stain are best done with young culture (12-24 hours) and it will retain stain for (less than 1 day minimum)
Gram stain are best done with young culture (12-24 hours) and it will retain stain for (less than 1 day minimum)
answer
True
question
Colony
answer
visible mass on media
question
Pure culture
answer
a population descended from a single cell
question
True or False
streak plate gives pure cultures
streak plate gives pure cultures
answer
True
question
Streak plate purpose
answer
to dilute bacteria on media so they will only grow in isolated colonies
-can also distinguish color and shape
-can also distinguish color and shape
question
True or False
Closer streak lines dilute bacteria more evenly
Closer streak lines dilute bacteria more evenly
answer
True
question
Sulfonamides are unique because they display ____
answer
selective toxicity (kill or inhibit bacteria without killing host)
bacteriostatic not bactericidal
bacteriostatic not bactericidal
question
How does sulfonamides only effect bacteria?
answer
Bacteria: PABA --> folate --> coenzyme F
Human: folic acid from diet --> folate -- coenzyme F
* prevents PABA to folate
Human: folic acid from diet --> folate -- coenzyme F
* prevents PABA to folate
question
Sulfa drugs ____ inhibit PABA because their structures are ___
answer
competitively inhibit
analogues/very similar
analogues/very similar
question
How to reverse PABA inhibition effects caused by sulfa
answer
-add extra PABA to out compete Sulfa
-add amino acids to skip folate synthesis
-add amino acids to skip folate synthesis
question
Glucose tube only (SULFA)
answer
control: to make sure bacteria can grow (positive control)
question
glucose + sulfa
answer
no growth
question
glucose + sulfa + PABA
answer
growth (shows bacteriostatic)
question
glucose + sulfa + TSY
answer
growth because nutrient provided in media for bacteria to skip folate synthesis
question
Inhibiting growth of bacteria can treat UTI because...
answer
your immune system can catch up after growth is inhibited
question
obligate aerobes
answer
-need O2 to survive
-generate H2O2
-usually produce catalase to break down H2O2
-generate H2O2
-usually produce catalase to break down H2O2
question
obligate anaerobes
answer
-kill in O2, don't need it
-no catalase
example is botulism bacteria
-no catalase
example is botulism bacteria
question
facultative anaerobes
answer
will use O2 for metabolism if available
-produce catalase
example: E Coli
-produce catalase
example: E Coli
question
microaerophilic
answer
need O2 but only tolerate small amount
question
aerotolerant anaerobe
answer
grow in O2 but not used in metabolism
question
Why do you boil agar in the aerobic/anaerobic growth experiment for 10 mins?
answer
TO drive off O2 diffused in agar
question
Obligate Aerobes (M. Luteus) grow on the ___ of tube
answer
top, near dissolved O2 (if there's any)
question
Obligate anaerobes growth ____ of tube
answer
bottom
question
facultative anaerobe grow __ of tube
answer
everywhere
question
True or False:
Vegetative cells can be killed by boiling
Vegetative cells can be killed by boiling
answer
True
question
True or False
Bacillus and Clostridium can produce endospore and resist heat, acidity, drying, irradiation
Bacillus and Clostridium can produce endospore and resist heat, acidity, drying, irradiation
answer
True
question
Endospores grow in response to ____
answer
depleting nutrients or adverse conditions (sporulation)
question
True or False
E Coli does not produce endospores
E Coli does not produce endospores
answer
True
question
Why do we incubate tubes with bacillus and E coli (heat sensitivity) after heat treatment?
answer
To see if any cells survived and grow
question
Validate plate count must contain ___ and __ colonies
answer
30 -300
question
Bacillus is killed at
answer
100 C
question
E coli is killed at
answer
75 C
question
True or False
UV light can't sterilize glass and dish because it can't penetrate glass or most substances?
UV light can't sterilize glass and dish because it can't penetrate glass or most substances?
answer
True
question
How does UV kill microbes?
answer
Cause extensive mutations in DNA (form covalent bonds between neighboring pyrimidines)
-DNA with thymine dimers can't replicate
-DNA with thymine dimers can't replicate
question
True or False
Thymine dimers are caused by UV exposure
Thymine dimers are caused by UV exposure
answer
True
question
Why should you not look directly to UV light?
answer
Damages eyes
question
Control in the UV experiment is done by....
answer
covering half of the dish with the lid to prevent UV exposure
question
E coli is ___ susceptible to UV than Bacillus
answer
more
question
Saliva is ___ susceptible to UV than E coli
answer
more
question
When will strep. salivarius produce gum drop colonies?
answer
When sucrose is present, salivarius will form polysaccharide capsule
question
When will strep. salivarius produce white and small colonies?
answer
no sucrose present on media
question
Strep. salivarius changes ___ when it encounters sucrose. Why?
answer
phenotype
different genes got turned on
different genes got turned on
question
TSY + sucrose media is ____
answer
differential: makes one kind more distinctive than another
-will show up as gum drops
-will show up as gum drops
question
Crown gall refers to.....
answer
infection occur at plant's root crown near soil surface
question
Agrobacterium enters hosts via....
answer
Ti plasmid then incorporates into host DNA
-causes tumor like growth
-causes tumor like growth
question
How does Agrobacterium makes itself more competitive by infecting plants?
answer
-production of opines (better competitor)
-nutrient for bacteria (only few can use opines)
-nutrient for bacteria (only few can use opines)
question
Why are soil organisms so important to our survival?
answer
They convert N2 (replenish) to ammonia (nitrogen fixation)
question
True or false:
Nitrogen fixation can be carried out only by prokaryotes
Nitrogen fixation can be carried out only by prokaryotes
answer
True
question
True or false:
Soil bacteria make antibiotics
Soil bacteria make antibiotics
answer
True
question
Clostridium is a _____ anaerobe
answer
obligate
question
Why did we do spread plates instead of pour plates to culture soil bacteria?
answer
To avoid the 50 C, which can kill some bacteria
question
Capek's agar contains .....
answer
mineral salts and sucrose
not differential or selective
not differential or selective
question
What do endospores look like after doing a Gram stain?
answer
Colorless body in Gram positive rod
question
Endospore stain procedure
answer
-cover smear with paper towel and flood with malachite green dye
-heat for 10 mins and keep towel wet
-wash with water
-decolorize smear for few seconds
-counterstain with safranin for 1 minute
-wash and blot dry
-heat for 10 mins and keep towel wet
-wash with water
-decolorize smear for few seconds
-counterstain with safranin for 1 minute
-wash and blot dry
question
In endospore stain, vegetative cells are ____ and endospores are ___
answer
safarin/red, green
question
Streptomyces look like ____
answer
hardened powder, small, not fuzzy
question
Conjugation
answer
DNA transferred via sex pili
question
Transduction
answer
bacterial DNA carried in phage
question
Transformation
answer
uptake of naked DNA from environment
question
Cells need to be ___ to do transformation
answer
competent
question
True or False
DNA being transferred must have observable characteristics/marker
DNA being transferred must have observable characteristics/marker
answer
True
You can check to see if DNA is uptake by the host by plating bacteria with antibiotics to see if resistance developed
You can check to see if DNA is uptake by the host by plating bacteria with antibiotics to see if resistance developed
question
Prototroph
answer
wild type strain of organism
can grow on minimal medium
can grow on minimal medium
question
Mutant/auxotroph
answer
can't synthesize ___ essential nutrient and need richer medium for growth
question
Antibiotics inhibit bacteria by interfering with (3)
answer
cell wall synthesis
protein synthesis
DNA replication
protein synthesis
DNA replication
question
Streptomycin stops ____ by binding to ___
answer
protein synthesis, 70S ribosome
question
____ are selected during antibiotic therapy
answer
resistant mutant
question
Why did you lay the bottles on their side for the antibiotic resistant mutant lab?
answer
to increase aeration
question
True or False
It is possible that a mutation occur and the bacteria need streptomycins to grow (can't grow on TSY plates)
It is possible that a mutation occur and the bacteria need streptomycins to grow (can't grow on TSY plates)
answer
True
question
The antibiotic resistant mutant lab is an example of ____ selection
answer
direct
directly selecting for the antibiotic resistant form
directly selecting for the antibiotic resistant form
question
Why is it impractical to test the water for individual pathogens? (3)
answer
-pathogens usually present in low numbers, hard to detect
-no single method for isolating all pathogens
-no safety margin to avoid illness
-no single method for isolating all pathogens
-no safety margin to avoid illness
question
indicator organisms
answer
normal microbiota, indicates fecal pollution
question
narrow spectrum antibiotics
answer
kill narrow range of bacteria
question
broad specter antibiotics
answer
kill wide range of bacteria
question
aerial hyphae production (powdery appearance)
answer
respond to nutrient limiting conditions
question
phage infect.....
answer
bacteria
aka phage particles
aka phage particles
question
True of False
Phage can replicate by itself
Phage can replicate by itself
answer
False
They need a host
They need a host
question
lambda attaches to ___ receptor
answer
maltose transport
question
True or False
Phage can have both DNA and RNA genome
Phage can have both DNA and RNA genome
answer
False, only one or the other
question
lysogenic cycle
answer
phage resides within host, does not lyse cells
-integrates DNA into host DNA
-integrates DNA into host DNA
question
prophage
answer
host with integrated viral DNA
question
Phages can turn off viral protein product by having ....
answer
repressor protein, prevent re infection from the same type of phage
question
bioluminescence requires (2)
answer
luciferase protein and oxygen
question
quorum sensing
answer
monitor the neighboring cell population
-high density will luminescent
-low density will NOT luminescent (too high of ATP cost)
-high density will luminescent
-low density will NOT luminescent (too high of ATP cost)
question
True of False
Bioluminescent bacteria will only produce light when it has enough bacteria to produce a noticeable light source that will attach prey
Bioluminescent bacteria will only produce light when it has enough bacteria to produce a noticeable light source that will attach prey
answer
True
question
autoinducer
answer
signaling molecule used in quorum sensing to sense the size of the population
-more autoinducer, bigger population
-more autoinducer, bigger population
question
True or False
Urine in bladder is usually sterile
Urine in bladder is usually sterile
answer
True
question
True or False
Most common source of UTI comes form patient's own fecal microbiota
Most common source of UTI comes form patient's own fecal microbiota
answer
True
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