BIOL 3201 Final Exam

What is BSL 1?

Microorganisms not known to cause disease in healthy adults.

What is BSL 2?

Indigenous microorganisms that can lead to diseases of varying severity in healthyadults.

What is BSL 3?

Indigenous or exotic microorganisms that cause serious or potentially lethal diseasethrough respiratory transmission.

What is BSL 4?

Microorganisms that are dangerous and exotic with high risk of aerosol transmitted infections.

What is a microorganism?

living organisms that cannot be seen without a microscope

What does ubiquity mean?

everywhere

What does sterile mean?

free of microbial contamination

What is contamination?

undesired introduction of impurities

What is agar?

solid media from red algae

What is a Petri dish?

dish used to culture bacteria

Who worked on the creation of the Petri dish?

Julius Petri and Robert Koch

What is a pure culture?

only one type of microbe

What is aseptic technique?

set of precautions to avoid contamination

What is a disinfectant?

destroy bacteria and viruses but not endospores

What color does a loop turn when it is ready for aseptic technique?

red hot

Why should you wait to use your loop after heating?

it can kill the bacteria

What is a bright field microscope?

light is passed through or reflected off of a specimen

Do you need stains to use bright field microscopy?

Yes

What is a phase contrast microscope?

enhances contrast

Are stains required for phase contrast microscopes?

No

What is a dark field microscope?

bright specimen on dark background

Do you need stains for dark field microscopes?

No

Can you see internal structures with dark field microscopy?

No

What is a fluorescent microscope?

requires use of fluorophores

What is the most common microscope?

bright field microscopes

What is the frame of a microscope composed of?

arm and base

What is the stage of a microscope?

horizontal area that supports the microscope slide

What are the three lens systems of a bright field microscope?

oculars, objectives, and condenser

What are the three objectives of a bright field microscope?

10X, 40X, and 100X

What is total magnification?

ocular lens x objective lens

What does the condenser do?

collects and directs light

What does the diaphragm do?

controls the amount of light

What is the coarse focus knob?

outer knob

What is fine focus knob?

inner knob

When is immersion oil used?

100x

What does parfocal mean?

the lens stays in focus when objective is changed

What is numerical aperture?

the ability of a lens to gather light

What is resolving power?

ability to show detail

What is working distance?

distance between objective lens and specimen

Why are bacteria transparent?

80% water

What is the most common mistake of smear prep?

too much bacteria

What type of stain is a Gram stain?

differential stain

What color is a Gram positive stain?

purple

What color is a Gram negative stain?

pink

What is being dyed in a Gram stain?

peptidoglycan cell wall

Does a Gram positive bacteria have a thick or thin layer of peptidoglycan?

thick

Does a Gram negative bacteria have a thick or thin layer of peptidoglycan?

thin

What is the mordant in a Gram stain?

Gram's Iodine

What is the counter stain?

safranin

What is the primary stain?

crystal violet

What is used to decolorize Gram negative bacteria?

ethanol

What shape are cocci?

spheres

What shape are bacilli?

rods

What are aerobic bacteria?

require oxygen for growth

What do aerobic bacteria use as their terminal electron acceptor?

oxygen

What is hydrogen peroxide?

oxidizing agent

What do aerobes produce to combat the effects of hydrogen peroxide?

catalase

What does catalase turn hydrogen peroxide into?

water and oxygen

What are strict anaerobes?

cannot grow in the presence of oxygen

What does aero-tolerant mean?

anaerobes that tolerate oxygen

What are facultative anaerobes?

grow by respiration or fermentation

What two types of bacteria do not produce catalase?

aerotolerant and strict anaerobes

What does a positive catalase test do?

bubble

What does a negative catalase test do?

no change

The oxidase test tests for the presence of what enzyme?

cytochrome oxidase

What does a positive oxidase test do?

turns blue

What does a negative oxidase test do?

no change

What test confirms a Gram stain?

KOH

What does positive KOH test do?

strings present

If there are strings present in a KOH test, the bacteria is?

Gram negative

What does a negative KOH test do?

no change

If there are no strings present in a KOH test, the bacteria is?

Gram positive

What are the three primary tests?

catalase, oxidase, KOH

What is a selective medium?

allow only certain microorganisms to grow and will inhibit the growth of other microorganisms

What media is both selective and differential?

MSA

What does MSA stand for?

Mannitol Salt Agar

What makes MSA selective?

sodium chloride

What is a differential medium?

cause some bacteria to take on an appearance that distinguishes them from other bacteria

What makes MSA differential?

mannitol

What type of medium is SBA?

differential

What is beta hemolysis?

complete hemolysis

What is alpha hemolysis?

partial hemolysis

What is gamma hemolysis?

no hemolysis

What color does alpha hemolysis turn?

green

If an organism can break down a carbohydrate, what is usually produced?

acid

What is a starch molecule made out of?

amylose and amylopectin

What is the reagent for starch hyrdolysis?

Gram's Iodine

What is a starch hydrolysis test testing for?

production of amylase

Why is it important to air dry and heat fix smear prep slides before Gram staining?

So bacteria does not wash off

Staphylococcus aureus is the only Staphylococcus species in your lab reading that gives a positive coagulase result.

True

Bacteria that are aero-tolerant anaerobes carry out metabolism by...

Fermentation only

What color is a positive MSA test?

yellow

What color is a negative MSA test?

remains red

What does a positive starch hydrolysis test look like?

Dark agar with clear zone around streak line

What does a negative starch hydrolysis test look like?

Dark agar up to the streak line

What are the three selective mediums we use in lab?

bile esculin hydrolysis, MSA, and EMB

What does a positive BHI with 6.5% NaCl test look like?

turbid

What does a negative BHI with 6.5% NaCl test look like?

no growth

What does bile esculin hydrolysis test for?

ability to hydrolyze esculin to esculetin and dextrose

What is the reagent in a bile esculin hydrolysis test?

ferric acid