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