BIOL 2051 Lab Midterm LSU

this name is unique to each species and consists of a genus followed by a species name

binomial name

an organism, which has not yet been officially named

strains

show how one organism is related to another one

phylogenetic tree

contains nutrients, such as carbon and nitrogen, required for cells to grow

culture medium

composed of digest of chemically undefined substances such as yeast and meat extracts

complex medium

on for which a precise chemical composition is known

defined medium

used for isolation and growth of microorganisms, solid media in a petri dish

plates

test tubes containing solid medium, which has been allowed to solidify in an upright position, and are usually used for anaerobic growth

deeps

deeps are usually used for what?

anaerobic growth

test tubes continuing sold medium that has been allowed to solidify at an angle and the surface of the agar is used for the maintenance of stock cultures of microorganisms

slants

slants are usually used for what?

the maintenance of stock cultures of microorganisms

the killing or removal of all living organisms and their viruses from a growth medium

sterilization

a sealed device that allows the entrance of steam under pressure

autoclave

the autoclave is heated at what temperature?

121 deg C at 15 lb per square inch

kills bacteria by oxidative effects

Dry heat sterilization

What are autoclaves generally used for?

sterilize liquid media and other items that are heat resistant

one of the simplest methods of dry heat sterilization, used to sterilize inoculating loops

flaming

items to be sterilized are placed in an oven and heated to 170 deg C for 2 hours

hot air sterilization

Hot air sterilization is used to sterilize what?

glassware

a device with pores too small for the passage of microorganisms but large enough to allow passage of the liquid or gas

filtration

What is an example of an item sterilized by filtration?

beer

Heat sensitive objects like plastic petri dishes are sterilized using what method?

gaseous chemosterilizers

What is a widely used gas for chemosterilization?

ethylene oxide

a method of sterilization used to sterilize wood, metal, and rubber products where no heat is used in the process.

cold sterilization

includes microwaves, UV radiation, X-rays, gamma rays and electrons; type of sterilization

electromagnetic radiation

causes damage to DNA (thymine dimers) leading to death of exposed organisms

UV radiation

causes ions and other reactive molecules to be produced and these reactive molecules can degrade or alter biopolymers such as DNA and proteins

ionizing radiation

Name two examples of how radiation can be used.

in the food industry and for sterilization and decontamination of medical supplies

How could bandages be sterilized?

ionizing radiation

disease causing microorganisms can be classified as _______.

pathogenic

hospital acquired infections

nosocomial

a group of genetically identical bacteria, arising from a single cell on an agar plate

colony

the number of microorganisms or viruses sufficient to establish an infection

infectious dose

microorganisms that establish themselves on or in the body, but do not produce disease under normal conditions

normal flora (microbiota)

may be present on the body temporarily but do not become firmly entrenched

transient flora (microbiota)

ranging from ph 4-6

acidic

characteristics of colonies, such as the shape of the colony, the form of the colony margin, and the elevation and pigmentation of the colony, are visible to the naked eye

colony morphology

an unwanted organism which hans been accidentally introduced into a culture

contaminant

What can influence the colony morphology properties of a microorganism?

the medium that the microorganism is placed on because the type and amount of nutrients offered effects the size, shape, and color of the colony

a culture containing a single kind of organism

pure culture

a dilution technique used to isolate a pure culture; the bacteria in a mixed culture will be diluted in order to separate the organisms and isolate each in pure culture

streak plate

If there is a positive result when the expected result is negative, this could mean the presence of unwanted organisms called__?

contaminants

this technique must be used to observe microorganisms and the total magnification achieved is 1000x

oil immersion objective

This technique adds contrast and makes cells more visible

staining

this is made from cultures in liquid or on solid medium and the procedure varies slightly with the culture medium used.

smear

this process kills the cells, destroying autolytic enzymes, and causes the cells to adhere to the slide

heat fixation

adhesion of the cells to the slide is essential because ?

if the cells do not adhere they will wash off during staining

bacillius is another word for____

rod

cells that are arranged in pairs are ____.

diplo

cells that are arranged in chains are_____.

strepto

cells that are arranged in clusters are ____.

staphylo

cells that are round are _____

cocci

grouse of four cocci are called _____

tetrads

Cellular morphology, looks like curved rods

vibrios

a helical shape that is rigid

spirilla

helical and flexible and resemble a corkscrew

spirochetes

organisms that produce pros thecae, cellular appendages that increase cell surface are and hence help the transport of nutrients into the cell

prosthecate cells

cellular appendages that increase cell surface area and hence increase transport of nutrients into the cell

prosthecae

growth that produces filaments or hyphae that form a mycelium (network of hyphae) the hyphae later differentiate and fragment to produce spores

filamentous growth

Name a bacteria that uses filamentous growth

actinomycete bacteria, Streptomyces coelicolor

network of hyphae

mycelium

filaments are also known as ____

hyphae

an aqueous or alcohol solution of a single basic dye

simple stain

What are the three principle cell shapes?

coccus, bacillus, spirillum

Explain why staphylocbacilli do not exist

Because staphylobacilli only divide along the vertical axis, therefor making it impossible to form clusters of rods

Name the type of light microscope that we use in lab

bright-field microscope

a microscope that consists of a series of ocular and the objective lenses

compound microscope

having an ocular containing a magnifying lens for each eye

binocular

the produce of the magnification of the ocular lens and the magnification of the objective lens

total magnification

magnification is limited by a property of the lenses called _____

resolution

the closest spacing between two points at which the points can still be seen as separate entities

resolution

Resolving power depends on the ________ and a property of the objective lens called the ___________

wavelength of light, numerical aperture

has the same refractive index as the glass slide and lens, placed between the specimen and an oil immersion lens

immersion oil

upon this a slide holding the smear or wet mount will be placed

stage

the ______ source is located at the base

light

the light in a microscope passes from the source through a _________

condenser

a lens that collects and concentrates the light onto the object on the stage

condenser

this can be opened or closed to allow more or less light through to the stage

iris diaphragm

your microscope is _______ meaning that as the objective lens is changed, the specimen should remain in focus

parfocal

an example of a differential stain is _____

a gram stain

repeating disaccharides attached by a polypeptide to form a lattice

peptidoglycan

Gram ______ bacteria have many layers of peptidoglycan which make the structure rigid

positive

In addition to a thick peptidoglycan layer, most gram positive bacteria contain _______ acids

teochoic

gram ______ bacterial cell walls consist of few layers of peptidoglycan surrounded by an outer membrane

negative

What is the primary stain of a gram stain?

crystal violet

What is the mordant of the gram stain?

iodine

What is the decolorizing agent of a gram stain?

ethanol

What is the counterstain of the gram stain?

sarfranin

gram positive bacteria will stain _____,gram negative bacteria will stain _____.

purple, red

What is the function of the mordant in a gram stain?

the mordant complexes with the crystal violet, making it too large inside the cell to come back through the peptidoglycan layer

What would be the appearance of all cells in a gram stain if the decolorizer was not added?

the gram negative cells would not show up

What would be the appearance of all cells in a gram stain if the smear were over decolorized?

the gram positive cells would not show up

Why is a counterstain added to a gram stain?

so the gram negative cells can be visible

a specialized dormant structure that is commonly found in certain gram positive rods such as those of the general Clostridium and bacillus

endospore

a cel that can grow and divide under optimal conditions

vegetative cell

a stage in which no metabolic activities are occurring

cryptobiotic state

the process of endospore formation within vegetative cell

sporulation

an ingrowth in the plasma membrane

spore septum

the ______ becomes a double-layered plasma membrane surrounding the genetic material and at the stage the structure is termed a forespore

spore septum

when the endospore has developed a double layered plasma membrane surrounding the genetic material it is in a stage known as the ______

forespore