Lab Practical 1

A ____ consists of one or more species of microorganisms growing in a nutrient growth medium often at specific temp

A culture consisting of ONLY 1 species of microorganism is called a what?

The composition of nutrients that all organisms require to grow and survive is called a ___ medium.

A liquid solution in which microbes, especially microbes & protozoa, will grow is known as a ___ ___.

A broth supplemented with a solidifying agent that produces a relatively solid medium on which bacteria and fungi easily grow is called what?

Agar is a polymer of what extracted from what?

Agar liquifies at ___^o C and solidifies at ___^oC.

Describe a "circular" form of a colony.

What type of microscope utilizes visible light to magnify and resolve objects?

Which staining technique uses 2 contrasting colored stains to allow bacteria to be separated into 1 of 2 grps and also visualize structures such as endospores and capsules?

What are the 3 purposes of simple staining?

What are the 3 main purposes of differential staining?

Define working distance as it relates to microscopy.

What aspect of microscopy pertains to the light-bending ability of glass, oil and air media thru which light must pass during image formation?

What are 3 types of basic stains?

Basic stains carry a ___ electrical charge.

The ___ stain technique allows us to see unstained bacteria on a stained background and determine their morphology.

____ stains such as nigrosin, congo red & india ink carry a neg charge & are therefore what?

What are the steps in preparing a bacterial smear?

Define a bacterial smear.

If agar slants are used when making a bacterial smear then a what should be added to the slide as well?

What are the 3 things accomplished by heat fixing?

Simple staining is an easy way to determine what 3 things about bacterial cells?

Name 3 basic stains we discussed?

The ___ ___ technique permits one to see unstained bacteria on a stained background & determine their morphology.

Nigrosin, congo red & India ink are ___ stains that carry a ___ charge and are therefore repelled by ____ charged bacteria.

What form of bacteria found in dental plaque are best stained in a negative manner and why?

The use of excessive stain when utilizing the negative stain technique causes what problem?

Negative stain must not be allowed to become contaminated because. . . . 

What is the quick procedure for the negative stain technique?

What are 2 advantages to the negative stain technique?

T or F. Negatively stained slides are air dried and heat fixed.
True False

When the negative stain technique is used what are we looking for in the microscope?

When labeling a diagram of a slide what should we note?

What is a second method for preparing a negative stain?

Why do we not heat fix bacterial smears iN negative staining?

What is aseptic transfer?

Why do we use aseptic technique?

What is the red pigment produced by S. marcescens called?

What are 3 advantages of the streak plate technique over the pour plate technique?

Why do we incubate plates in the inverted position?

In 1884 ___ ___, a Danish physician, discovered certain bacteria aft being stained w/crystal violet & iodine, would lose their color on subsequent tx w/alcohol while other bacteria would retain the color.

When Gram staining bacteria that retain crystal violet stain are known as ___-___ & those that do not are ___-___.

Gram staining is classified as a ____ staining technique.

What 2 types of bacteria do not respond to Gram staining?

___ ___ & ____ form a complex that exits easily fr Gram neg bacteria but not fr Gram pos when ___ is applied.

What is it in the cell walls of Gram positive bacteria that trap the crystal violet/iodine complex?

What is it that makes Gram pos cell walls retain the crystal violet/iodine complex and causes Gram neg walls not too?

The Gram stain technique is a ___ part procedure in which 2 dyes, a ____(iodine) & a ___ agent are used.

Other than a culture what supplies are needed for a Gram stain procedure?

What are the steps in a Gram stain?

The iodine in a Gram stain acts as a mordant which means what?

As a general rule how long should decolorization go on for?

What is the possible result of excessive decolorization in Gram staining?

What is the possible result of insufficient decolorization when performing a Gram stain?

Prior to counterstaining in the Gram technique what would the slide look like under a microscope?

What effect will safranin have on Gram pos bacteria?

After decolorization, flood smear w/____ for ___ secs.

Gram pos bacteria will appear ___ to ___ & Gram neg will appear ____ to ____.

When observing Gram stained slides, be sure to confine your work to areas containing thin smears of bacteria b/c why?

Endospores are formed by members of several gram-___ bacterial genera such as ____ &____.

What are 3 characteristics of endospores?

What happens to spores when the chem environment are favorable?

Name 4 notable diseases caused by sporeformers.

What name is given to a layer of polysaccharides & proteins secreted by certain bacteria including pathogens? 

What functions does a capsule perform?

A thin flowing capsule isnt really a capsule at all. It is called a ___ ___.

The term ____ refers to both capsule and slime layer

____ are protein appendages that facilitate motion of bacteria?

Many species of bacterial ___ & ___  & a few species of ___ possess flagella

Why is it that flagella are so long but cannot be seen with a light microscope?

What is the purpose of the spore stain technique?

Why is it that bacterial endospores cannot be penetrated easily by stain using simple or Gram stain techniques? 

What do we do to assist with stain penetration when staining bacterial endospores?

What stain do we use as the primary stain for spore stain?

When doing a spore stain we should allow the slide to remain over ___ for ___ mins, continually adding stain. 

Heat during spore stain does what?

When rinsing spore stained slides vegetative cells will ___ their color while endospores will what?

When spore staining we counterstain w/___ for __ min.  This will have what effect?

When spores are found within vegetative cells, their position could be ___, ___ or ___.

Young cultures often contain spores within ___ ___ while older cultures contain more free ___ & fewer ___ ___.
 

When utilizing the alternate spore stain technique, we cover the smears w/___ ___ ___ for how long?

Visualization of the bacterial capsule by staining is a 2-step procedure involving both ___ & ___ staining.

Why is it that water or heat should not be used in any step of capsule staining?

Why is it helpful to use milk cultures of organisms when capsule staining? 

What are the quick steps to produce a capsule stain?

When viewing capsule stain, what are we looking for?

What are 2 methods for determining motility?

What characteristics of motility should we not when viewing our slide?

Erratic vibrations of cells in place & lack of directed mvmt demonstrates a phenomena called what? 

What causes Brownian mvmt?

What is motility test agar?

What is special about semisolid motility agar?

How will motile organisms present in test agar in comparison to non-motile organisms?

Name 3 characteristics that are used to help ID an organism.

Why is it necessary to invert plates when incubating them?

In ____ colonies, bacteria form many hairlike filaments as they grow outward from the center of the colony.

____ colonies grow outward in fewer and thicker filaments, like the roots of a miniature tree.

____ colonies bulge up from the plate in a pronounced semicircle.

____ colonies look like raised colonies, but they have a small projection in the middle.

____ colonies resemble raised colonies, but they have a tiny depression like a dimple in the middle.

The ___ describes the edge of a bacterial colony.

A colony where the edge is lumpy and irregular is considered to be what shape?

Some margins are ____, with tiny filamentous strands of bacteria growing out from a central mass.

____ margins have a wavelike edge, while ____ margins have fingerlike projections growing outward from the edges of the colony.

Cloudyness in a broth culture is described as being ____.

A broth culture that contains small particles is said to be what?

A broth culture that contains small masses is said to be ____.

Broth cultures that contain large particles are described as ____.

Sediment at the bottom of a tube that clumps together is said to be ____.

Aerobic growth is located where in a thioglycollate medium tube?

Growth at the bottom of a thioglycollate tube indicate what type of growth?

Growth throughout a thioglycollate tube indicates what type of growth?

Why is it said that biochemical characteristics serve as fingerprints for a bacterial species?

What is contained in Bergey's Manual of Systematic Bacteriology?

___ is a type of microbial metabolism which an organic intermediary molecule serves as an electron acceptor  

What are the two products of fermentation that our tests looked for?

What is the media used in fermentation testing consist of?  

For our carbohydrate test we used phenol red indicator.  This solution is ___ in neutral or basic solutions & ___ in acidic solutions.

What item was added to our fermentation test tubes to indicate the formation of gas?

____ is a poly saccharide consisting of thousands of glucose molecules chemically bonded to one another.

Certain bacteria utilize this enzyme to biochemically break bonds between glucose monomers.

What indicator do we use to test for starch digestion and how does it indicate?

What does starch normally do in the presence of iodine?

Catalase is an enzyme that breaks down ___ ___ to ___ & ___.

Why is catalase important in the bacterial metabolism?

What happens if hydrogen peroxide fr energy yielding processes is not broken down by catalase?

Why is hydrogen peroxide generally a poor antiseptic?

How can we test for catalase production?

How do we know if catalase is being produced by a bacteria?

Certain bacteria produce the enzyme ____ which digests DNA into its constituent nucleotides.

How is the DNA test performed?

What chem is added to a culture grown on what med to determine if DNA has been digested?

DNA will normally react w/HCL & form what?

If DNA digestion has occurred the area nr the bacterial streak will be ____ & the remainder of the plate will become ___.

The enzyme ___ ___ breaks down the amino acid cysteine to form ___ & ___ ___.

When testing for hydrogen sulfide, if Fe ions are present what happens?

Hydrogen sulfide has significance in the food industry.  Why?

What medium is commonly used for the hydrogen sulfide test & what does it contain?

What 3 things can be tested in SIM medium?

___ is an end product of protein metabolism in bacteria.

Certain bacteria produce the enzyme ___ which breaks down urea into ___ & ___.

Urea digestion is important in ___ cycles in the soil b/c urea is a major component of animal ___ & bacteria are responsible for ___ ___ ___ to release nitrogen for reuse.

In the test for urea digestion, bacteria are inoculated to a nutrient broth that contains what 2 things?

If urea is digested during incubation, ammonia will ___ the pH of the medium and cause the indicator to become what color?

Certain bacteria secrete enzymes called lipases that ___ the ___ in lipids.

When lipase hydrolyzes linkages in lipids, what is separated?

What happens to glycerol & fatty acid molecules that result fr lipids broken down by lipases?

What is the name given to a type of food spoilage in which foul odors & flavors develop b/c of fatty acids released fr lipids

What 3 foods are particularly susceptible to rancidity? 

What special medium is used to test for lipid digestion?

Spirit blue agar is rich in ___ & contains spirit blue which is an indicator for what?

Spirit blue agar is ___ ___ in a neutral environment but becomes ___ ___ in the presence of acids.

If spirit blue agar becomes then the bacteria being tested are what causing what?