HOL Lab Final

Agent naturally produced by microorganisms.

Antibiotic

Agent artificially synthesized or manipulated from other products.

Antimicrobial

When one bacterial cell undergoes binary fission, there will be _____ cells present on the 5th generation.

16

Performing a 1:8 dilution from the original sample 3 times would produce a dilution of _____.

1:512

Plates with _____ colonies per plate are used to calcuate CFUs.

30-300

A viable plate has a count of 95 colonies produced from 0.125 mL of a 10-4 dilution of the original sample. The original contains _____ CFU/mL.

7,600,000

The measure of the light intensity absorbed by a sample

Absorbance

Metabolic process resulting in oxygen and peroxide by-products

Aerobic respiration

_____ are rod-shaped bacteria 0.5 - 20 µm in length.

Bacilli

____ is a genus that produces antibiotics.

Bacillus Cephalosporium Streptomyces

Agent that kills bacterial upon exposure.

Bactericidal

Agent that slows the growth of bacteria.

Bacteriostatic

Asexual reproduction resulting in two daughter cells

Binary Fission

Identifies metabolic properties of microbes

Biochemical test

Agar plates should be labeled on the _____.

Bottom

Anaerobic metabolism that produces acetoin

Butanediol fermentation

Enzyme that mediates the breakdown of hydrogen peroxide

Catalase

A spherical bacteria with a diameter of approximately 0.5 µm

Coccus

A viable plate count is a method of calculating the number of cells in a dilution by the counting the number of _____ on agar plates.

Colonies

Describes individual colonies on a plate's surface

Colony forming unit

Acidic stain repelled by the cell's surface

Congo red

_____ are asexually-produced spores of the Penicillium fungus.

Conidia

_____ is a common, harmless microbe used in laboratory studies.

Escherichia coli Saccharomyces cerevisiae Staphylococcus epidermidis

A pure plated culture should exhibit colony-forming units with two or more morphologies. T/F

False. A pure culture will produce colonies with identical morphologies.

An antibiotic is a synthetic drug produced in a laboratory. T/F

False. Antibiotics are directly synthesized by a microorganism. In contrast, antimicrobial agents may be derived from synthetic origin

Binary fission is a method of sexual reproduction where a single cell (parent cell) will split into four cells (daughter cells). T/F

False. Binary fission is a method of asexual reproduction where a single cell will split into two daughter cells.

Fermentation occurs when carbohydrates are broken down aerobically. T/F

False. Fermentation occurs when carbohydrates are broken down anaerobically.

Gram-positive bacteria have an outer cell membrane containing endotoxins. T/F

False. Gram-pos bacteria have an outer cell membrane lacking endotoxins

Heat fixing is required for the negative staining process. T/F

False. Heat fixing is not used in negative staining, only direct staining.

The depth of field is independent of the total magnification factor. T/F

False. Like field of view, the depth of field is dependent on the total magnification factor

When creating a wet-mount slide, an individual should drop the coverslip on the top of a water droplet placed on the slide without touching it to the slide first. T/F

False. One edge of the cover slip should be touching the slide before it is dropped onto the water droplet.

Resistant bacteria will exhibit a large zone of inhibition during a Kirby-Bauer diffusion test. T/F

False. Resistant bacteria will exhibit no zone of inhibition during a Kirby-Bauer diffusion test.

To create a series of dilutions, an identical volume of stock (undiluted) solution is added to each of the dilution test tubes. T/F

False. Stock (undiluted) solution is added to the first test tube.

Streak plating is performed by pouring broth onto agar plates. T/F

False. Streak plating is performed by spreading a bacterial sample on the surface of an agar plate with an inoculation loop.

The effective zone of inhibition is the same for all antibiotics. T/F

False. The diameter of the zone is dependent on the sensitivity of a microorganism to a particular antibiotic and the physical properties of the antibiotic itself.

The oil immersion lens provides optimal viewing of large specimens. T/F

False. The oil immersion lens provides optimal viewing of small specimens.

Zones of inhibition should be measured after they exceed 25 mm. T/F

False. Zones of inhibition should be measured once there is evidence of bacterial growth on the agar plate.

Visible area of a slide that can be observed

Field of View

Binds with bacterial ribosomes to prevent cell growth and cell division.

Gentamicin

Gentamicin is synthesized by a _____.

Gram-pos bacteria

Anaerobic metabolism that produces acids, alcohol, and gases

Mixed acid fermentation

Penicillin is produced by a _____.

Mold

To determine the number of CFUs in the original culture, the number of colonies on the viable plate is _____ the total dilution factor of that plate.

Multiplied by

Targets DNA gyrase, preventing DNA replication within a cell.

Novobiocin

Held by the turret closest to the stage, and range in power from 4x to 100x magnification

Objective lens

Eye piece that is typically 10X or 15X magnification

Ocular Lens

Disrupts cell wall stability, eventually leading to cell lysis.

Penicillin

The mold that Alexander Fleming observed preventing bacterial growth was _____.

Penicillium notatum

Mesh-like polymer present in bacteria cell walls

Peptidoglycan

_____ stains Gram-negative bacteria pink.

Safranin

Calculated by multiplying the magnification of the ocular lens with the objective lens

Total magnification factor

A compound microscope is a type of optical microscope. T/F

True

Agar is a solid media used in both slants and plates. T/F

True

All equipment and work surfaces should be cleaned with a bleach solution after contacting microbe cultures. T/F

True

Bacteriostatic antibiotics cause an inhibition of growth rather than cell lysis and death. T/F

True

Butanediol fermentation produces weaker acids than mixed-acid fermentation. T/F

True

Depth of field refers to the distance range that is in focus at a given time. T/F

True

Differential staining uses two or more dyes to stain structural components of a cell. T/F

True

Gram-positive cells have a thick outer cell wall composed of peptidoglycan. T/F

True

Many types of bacteria have gained resistance to antimicrobials at an astonishing rate.​ T/F

True

Morphology can be used to identify microorganisms with or without the use of a microscope. T/F

True

Negative staining results in a colorless cell on a stained background. T/F

True

Novobiocin is a bacteriostatic, narrow-spectrum antibiotic. T/F

True

Turbidity and flocculence are indicators of microbial growth in liquid media. T/F

True

When calculating total magnification of a microscope, both the ocular lens and the objective lens should be considered. T/F

True

Mixed-acid fermentation produces _____.

acetic acid ethanol hydrogen gas

Methyl red is a pH indicator that turns red in _____ conditions.

acidic

When transferring microbes from a broth to a plate, the inoculation loop should be sterilized _____.

before placing in broth after spreading microbes on the agar surface prior to disposal

The inoculation loop must be sterilized _____ when creating a streak plate.

before use between use in each quadrant after completing all quadrants

Bacteriocidal agents kill bacteria by _____.

cell wall lysis

The charge of _____ determines how dyes interact with bacterial cells during staining.

chromophores

A spreader is used when inoculating a Kirby-Bauer diffusion plate to _____.

create a uniform bacterial lawn

Slides should be rinsed after applying _____ during the Gram staining process.

crystal violet iodine decolorizer

In binary fission, bacterial cells grow _____.

exponentially

The main component of an optical microscope that is used to focus an image at a high power of magnification is the _____.

fine adjustment knob

Tryptic Soy Agar (TSA) is a _____ media.

general purpose solid

Catalase neutralizes the harmful effects of _____.

hydrogen peroxide

The products of mixed-acid fermentation _____ the pH of buffered media.

lower

Aseptic techniques are necessary to _____.

maintain safety isolate pure cultures prevent the spread of unwanted microbes

Biochemical tests are designed to identify _____ properties of microbes.

metabolic

The _____ is a biochemical test used to determine the identity of an unknown microbe.

methyl red test Voges-Proskauer test catalase test

Penicillin disrupts the formation of bacterial cell walls by inhibiting the formation of _____ cross-links.

peptidoglycan

The methyl red test detects a microbe's ability to _____.

perform mixed-acid fermentation

Gentamicin binds with bacterial _____.

ribosomes

Aseptic technique includes _____ .

working quickly and efficiently around open media containers not talking or breathing over open media containers washing hands before and after working with media

_____ is an example of a direct stain.

Crystal violet Methylene blue Safranin

Novobiocin is a bacteriostatic, narrow-spectrum antibiotic that targets _____ in some Gram-positive bacteria.

DNA gyrase

_____ washes dyes from Gram-negative bacteria.

Decolorizer

If the magnification of a compound microscope is increased from 10x to 100x, the field of view will _____.

Decrease

Distance range that is in focus at a given time

Depth of Field

The _____ sits below the stage and varies the field for viewing the specimen.

Diaphragm

A dye that stains only the cell leaving the background colorless

Direct Stain

_____ is a rod-shaped bacteria important to the study of genetics and evolution.

E. coli

The number of individuals doubles each generation

Exponential growth

_____ exist only as single cells and do not form clusters or chains.

Spirillum

The slide is placed on the _____ of an optical microscope.

Stage

Rod-shaped bacterial cells linked to form a chain

Streptobacilli

_____ are bead-like chains of spherical cells.

Streptococci

Cloudiness of a fluid caused by large numbers of particles/organisms

Turbidity

Butanediol fermentation produces _____ acids compared to mixed-acid fermentation.

weaker