Microbiology Lab Midterm questions
What are the three variable degrees of magnification of the objective lens?
- 10x - 40x - 100x
What are the four staining procedures used in a Gram Stain?
- Primary Stain - Mordant - Decolorizer - Counterstain
a living agent is a ___________ while a non-living agent is a _____________
- vector -fomite
List the steps to proper handwashing
- wash hands with soap and water for 20 seconds - scrub palms, fingers, tops of hands, between your fingers -rinse and dry off
What are the three endospore locations?
-Central -Subterminal -Terminal
True or False:Pure culture can easily be obtained on a streak plate even if the desired bacteria are present in very low concentration.
False
True or False:The stage of the microscope focuses light from illuminator to slide.
False
True or False:Viruses can be seen by using a compound light microscope
False
True or false: Microbiology is the study of organisms that can be seen with the naked eye
False
You only use ______ on 40x and 100x magnification
Fine adjustment knob
_______________________is used to decrease the amount of light that is refracted when using a compound light microscope to view a specimen at the highest level of total magnification.
Immersion oil
Why do you have to use immersion oil on 100X objective?
Immersion oil is used on 100x objective to form a bridge between glass slide and the lens, which reduced the amount of light lost due to refraction. Refractive index of the glass (1.56) and immersion oil (1.56) is higher than that of air (1.00), so light passes through the oil without bending.
The ________________ is used to transfer inoculum from culture plate or broth to new plate, broth, or microscope slide.
Inoculating Loop
The scientist who pioneered handwashing as a means of reducing disease transmission was:
Semmelweis
Organisms from the genus ______________________ do not gram stain
Mycobacterium
What are Mycolic acids?
Mycolic acids are waxy substances in the cell wall, the basis for acid fast reaction. They produce unusual permeability properties.
Microorganisms' that live naturally and permanently on our skin are called _____________________
Normal Flora
Permanent microbial residents (good bacteria) of the human body are called ___________________
Normal Flora
________________________ are infections acquired in hospital and healthcare facilities
Noscomial infections
A hospital acquired infection is also known as a/an __________________infection.
Nosocomial
Micro" refers to something large. True or False
false
The__________________________ is used for focusing with high power and oil immersion lens
fine adjustment
What can propel a bacteria through a liquid medium?
flagella
Threadlike appendages that are attached to bacterial cell walls and allow for bacterial movement are called _________________________
flagellates
_________ are NOT to be heat fixed
negative stains
What are the permanent, microbial colonists of the body called?
normal flora
___________ are permanent microbial residents of the human body.
normal flora
Hand washing prevents ______ infections
nosocomial
A microscope is said to be _____________________ if when one lens is in focus and the others are as well
parfocal
The first reagent is called the__________________
primary stain
Simple stains allow visualization for which of the following:
shape, size, arrangement
True or False:Gram Postive stains are purple and Gram negative stains are pink
true
True or False:The numerical aperture of the 40X objective is 0.65.
True
True or False:The ocular lens has a magnification of 10X.
True
True or False:Total magnification is ocular lens X objective lens.
True
True or false: The acid fast stain was made because of mycobacterium.
True
True or false:An example of a structural stain is a capsule stain.
True
What are the 5 I's used for culturing microbes in the laboratory?
-Inoculation -Incubation -Isolation -Inspection -Identification
What are the three mechanisms by which pathogens can enter the human body?
-Skin -Respiratory System -Digestive System
What are the four steps to putting a microscope away
1. Clean lens 2. Lower stage 3. Scanning power objective in position 4.Tighten silver knob
Explain the procedure to use a compound light microscope on 10X.
1. Turn on the illuminator to half power and open iris diaphragm 2. Use course adjustment to lower the stage 3. Set the scope to 10x objective and place slide onto stage 4. Use course adjustement to raise the stage 5. look through lens and adjust 6.Once in view use fine adjustment to fully focus
What are good safety guidelines to avoid contamination?
1. always wear gloves 2. always wear goggles (except when looking through microscope) 3. Carefully read and follow procedures 4. report any accidents or spills to instructor immediately
The total magnification of the lower objective on a microscope is :
100 (10x10)
Compound light microscopes magnify images up to _______________ their actual size
1000X
A specimen viewed with the oil immersion objective lens would have a total magnification of:
1000x
Immersion oil is used on which of the following lens
100x
Which objective do you use immersion oil?
100x
Only use course adjustment when viewing with ___.
10X OBJECTIVE
______________________ is a type of agar medium at an angle .
Agar slant
________________are used to provide all essential nutrients needed in order to culture microorganisms in a laboratory setting.
Artificial Media
The ______ is used to sterilize loop
BACTICINERATOR
Sterilize the inoculating loop using ____________________.
Bacticinerator
What is the instrument used for sterilization called?
Bactincinerator
The structure for a sphere is _____ and a structure for random clusters is ______.
COCCI; STAPHYLO
The primary stain used for acid fast stains is __________________.
Carbolfuchsin
What is a chemical group that imports color to benzene?
Chromophore
Which part of the microscope focuses light from the illuminator to the slide? Ocular lens
Condensor
The dormant structure formed within a microbial cell as a survival mechanism to resist damage from environmental factors:
Endospore
The class of microorganism that has membrane-bound nucleus and contains a complex cell structure is:
Eukaryotes
What type of microorganisms have a membrane-bound nucleus and organelles and can be uni- or multi- cellular with cell membranes and complex cell structures?
Eukaryotes
The 3 major classes of microorganisms are _______________________, ___________________________, and _________________________
Eukaryotes, prokaryotes, and viruses
TRUE/FALSE: Bacteria grow in pure culture in nature.
FALSE
TRUE/FALSE: Viruses can be viewed with the compound light microscope.
FALSE
T or F:A cell wall is requirement for all living things.
False
True or False: A non-living agent is a vector.
False
True or False: Broth is used when isolating, but not when culturing
False
True or False: Free-living microorganisms get nutrients from a host while parasitic microorganisms get nutrients from environment
False
True or False: Immersion oil act to decrease refraction of light and the increase magnification.
False
True or False: Prokaryotes have a membrane band nucleus
False
True or False: You should only use the coarse adjustment on the microscope with 100X objective.
False
True or False:Most of the type of bacteria present in our environment are pathogenic
False
True or False:One is NOT suppose to disinfect the bench and hands before starting class and after classes have ended.
False
____________________ are threadlike appendages attached to bacterial cell walls
Flagella
After a smear, the third of four steps to making a grain stain of your smear is:
Flood smear, with 95% ethanol for 1-3 seconds
You perform a Gram stain on a specimen. Under the microscope, you see spherical purple cells. This observation would indicate that the specimen is:
Gram positive cocci
___________________________bacteria have tufts of flagella located at one or both poles.
Lophotrichous
What is microbiology?
Microbiology is the research of organisms that can not be seen with the naked eye because of their small size. These organisms are called microorganisms and include bacteria, yeasts, mold, fungi, and viruses.
Describe the steps to a simple streak patter on Nutrient Agar.
Moisten a sterile cotton swab with distilled water, swab desired model, and then with a simple zig-zagged motion roll the cotton swab onto the agar in the plate. Be sure not to open it too long or too wide so that it doesn't get contaminated
For the Lab 1 experimental procedures, nutrient agar (NA) plates will be inoculated using which type of streak method?
Simple streak
Normal flora are found in
Skin, eyes, intestinal tract
Bacterial arrangement that can be seen in random clusters are called:
Staphylo
Round bacteria that lives in a cluster is ____________________
Staphylococcus
Bacterial morphology can be described as all of the following EXCEPT:
Strepto
Which of the following is used to describe a random cluster of bacteria?
Strepto
TRUE/FALSE: Glycocalyx capsules increase the virulence factor of microbes, which is the microorganism's ability to become a pathogen.
TRUE
TRUE/FALSE: Lab surfaces should be disinfected before and after experiments.
TRUE
TRUE/FALSE: Mycolic acids are waxy substances that give acid-fast cells a false positive Gram stain because they are resistant to decolorization.
TRUE
Name the major parts of a compound light microscope.
The major parts of a compound light microscope are the stage, the condenser, the iris diaphragm and the lenses (ocular lens, objective lenses).
True or False:Prokaryotes lack a membrane bound nucleus
True
How do you sterilize the inoculating loop in between uses?
To sterilize the inoculating loop between uses stick the loop inside of the bactincinerator for 5-6 seconds.
What is the process of streak plating?
To streak plate you must first get your sample, then begin streaking in only one quadrant of the media agar plate, you then streak from the first quadrant to the second and so on until al quadrants are done, Last the plates need to incubate, after incubation you should be able to see isolated colonies in the fourth quadrant.
True or False: Handwashing is the single most effective way to prevent the spread of pathogens
True
True or False: Viruses are too small to be seen with a compound light microscope
True
True or False:Acid Fast staining is useful to help identify mycobacterium
True
True or False:Gram-positive bacteria retain the primary stain after decolorizing with alcohol.
True
A ________________ is a population of genetically identical cells, arising from a single original cell.
colony
Peptidoglycan and teichoic acid form a molecular complex with________________________
crystal/violet iodine
A colony on an agar plate is a:
group of bacterial cells that are derived from a single original cell
A streak plate is used to :
isolate single colonies from identification
A ___________ culture has more than one bacteria shown on the agar plate
mixed