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Biol 1020 lab final Exam and A+
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Liquid media used to increase the number of microorganisms. - Broth Solid media used to isolate microbes - agar plate Normal flora bacteria used for studies involving osmotic pressure, antibiotic resistance, and biofilms. - S. epidermidis Clump of genetically identical microorganisms. - colony forming unit Single-celled fungi used for studies involving fermentation, genetics, and aging. - S. cerevisiae instrument used for spreading microorganisms across a streak plate. - Inoculation loop
- Agar plates should be labeled on the _____. - bottom
- Aseptic techniques are necessary to _____. a. maintain safety b. isolate pure cultures c. prevent the spread of unwanted microbes d. All of the above - d. all of the above Agar is a solid media used in both slants and plates. True False - true
- The inoculation loop must be sterilized _____ when creating a streak plate.
- before use
- between use in each quadrant
- after completing all quadrants
- All of the above - all of the above Morphology can be used to identify microorganisms with or without the use of a microscope. True False - true
- _____ is a rod-shaped bacteria important to the study of genetics and evolution.
- Escherichia coli
- Saccharomyces cerevisiae
- Staphylococcus epidermidis
- All of the above - E. coli
- 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
- All of the above - all of the above
- All equipment and work surfaces should be cleaned with a bleach solution after contacting microbe cultures. True False - true Tryptic Soy Agar (TSA) is a _____ media.
- general purpose liquid
- selective liquid
- general purpose solid
- None of the above - general purpose solid Streak plating is performed by pouring broth onto agar plates. True False - false-Streak plating is performed by spreading a bacterial sample on the surface of an agar plate with an inoculation loop. _____ is a common, harmless microbe used in laboratory studies.
- Escherichia coli
- Saccharomyces cerevisiae
- Staphylococcus epidermidis
- All of the above - all of the above 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
- All of the above - all of the above Turbidity and flocculence are indicators of microbial growth in liquid media. True False - true A pure plated culture should exhibit colony forming units with two or more morphologies. True False - false-should be identical morphologies Describes individual colonies on a plate's surface - colony forming unit
- All of the above - colonies Performing a 1:8 dilution from the original sample 3 times would produce a dilution of _____.
- 1:
- 1:
- 1:
- None of the above - 1: To create a series of dilutions, an identical volume of stock (undiluted) solution is added to each of the dilution test tubes. True False - false A viable plate has a count of 95 colonies produced from 0.125 mL of a 10-4dilution of the original sample. The original contains _____ CFU/mL.
- 760
- 12,
- 7,600,
- None of the above - 7,600, A spherical bacteria with a diameter of approximately 0.5 μm - coccus Rod-shaped bacterial cells linked to form a chain - Streptobacilli A dye that stains only the cell leaving the background colorless - direct stain Acidic stain repelled by the cell's surface - congo red Mesh-like polymer present in bacteria cell walls - peptidoglycan
- _____ are rod-shaped becteria 0.5 - 20 μm in length.
- Cocci
- Bacilli
- Spirillum
- All of the above - Bacilli
- _____ are bead-like chains of spherical cells.
- Tetrads
- Staphylococci
- Streptococci
- None of the above - Streptococci
- Negative staining results in a colorless cell on a stained background. True False - true
- _____ is an example of a direct stain.
- Crystal violet
- Methylene blue
- Safranin
- All of the above - all of the above Gram-positive cells have a thick outer cell wall composed of peptidoglycan. True False - true _____ washes dyes from Gram-negative bacteria.
- Crystal violet
- Iodine
- Decolorizer
- None of the above - decolorizer ____ exist only as single cells and do not form clusters or chains.
- Bacilli
- Cocci
- Spirillum
- All of the above - spirillum Differential staining uses two or more dyes to stain structual components of a cell. True False - true The charge of _____ determines how dyes interact with bacterial cells during staining.
- chromophores
- plasma membranes
- porins
- None of the above - chromophores _____ stains Gram-negative bacteria pink.
- Crystal violet
- Iodine
- Safranin
- All of the above - Safranin Gram-positive bacteria have an outer cell membrane containing endotoxins. True False - false-Gram-negative bacteria have an outer cell membrane lacking endotoxins. Heat fixing is required for the negative staining process. True False - false-Heat fixing is not used in negative staining, only direct staining.
True False - death Gentamicin binds with bacterial _____.
- ribosomes
- cell walls
- mitochondria
- All of the above - ribosomes The effective zone of inhibition is the same for all antibiotics. True False - 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. An antibiotic is a synthetic drug produced in a laboratory. True False - False ____ is a genus that produces antibiotics.
- Bacillus
- Cephalosporium
- Streptomyces
- All of the above - all of the above Penicillin is produced by a _____.
- bacteria
- mold
- virus
- All of the above - mold Novobiocin is a bacteriostatic, narrow-spectrum antibiotic. True False - true Gentamicin is synthesized by a _____.
- Gram-negative bacteria
- Gram-positive bacteria
- black mold
- None of the above - gram-positive bacteria Bacteriocidal agents kill bacteria by _____.
- cell wall lysis
- inhibiting ribosomal activity
- preventing cell division
- All of the above - cell wall lysis
Resistant bacteria will exhibit a large zone of inhibition during a Kirby-Bauer diffusion test. True False - false-Resistant bacteria will exhibit no zone of inhibition during a Kirby-Bauer diffusion test. A spreader is used when inoculating a Kirby-Bauer diffusion plate to _____.
- isolate individual bacteria colonies
- create a uniform bacterial lawn
- confine bacteria to one section of the plate
- None of the above - create a uniform bacterial lawn Zones of inhibition should be measured after they exceed 25 mm. True False - false _____ are asexually-produced spores of the Penicillium fungus.
- Aspergillus
- Bacillus
- Conidia
- None of the above - conidia Identifies metabolic properties of microbes - biochemical test Enzyme that mediates the breakdown of hydrogen peroxide - catalase Anaerobic metabolism that produces acids, alcohol, and gases - mixed acid fermentation Anaerobic metabolism that produces acetoin - butanediol fermentation Metabolic process resulting in oxygen and peroxide by-products - aerobic respiration Biochemical tests are designed to identify _____ properties of microbes.
- morphologic
- metabolic
- motility
- All of the above - metabolic Mixed-acid fermentation produces _____.
- acetic acid
- ethanol
- hydrogen gas
- All of the above - all of the above Methyl red is a pH indicator that turns red in _____ conditions.
False - true Oxygen ions and _____ are metabolites of aerobic respiration that can damage cell structures.
- alcohols
- peroxides
- mixed acids
- None of the above - peroxides _____ broth is used to culture microbes for the methyl red and Voges-Proskauer tests.
- MR-VP
- Phenol red
- Nutrient
- None of the above - MR-VP Red-stained media is a _____ result for the methyl red test.
- positive
- negative
- inconclusive
- None of the above - positive A positive Voges-Proskauer test appears as _____.
- solid red media
- solid yellow media
- a red layer atop yellow media
- None of the above - a red layer atop yellow media _____ is a positive result for catalase testing.
- Bubbling peroxide
- Red media
- Yellow media
- None of the above - bubbling peroxide A microbe produced positive methyl red results and negative Voges-Proskauer results. It can be concluded that the microbe _____.
- respires aerobically
- produces mixed acids but does not use the butanediol pathway
- uses the butanediol pathway but does not produce mixed acids
- None of the above - produces mixed acids but does not use the butanediolh pathway bacteria with numerous flagella at one end - lophotrichous bacteria with a single flagellum at each end - amphitrichous agents that prohibit the growth of some microbes - selective media
gel that prevents the diffusion of some microbes - motility media _____ is a form of functional media used to identify unknown microbes.
- Differential media
- Enriched media
- Selective media
- All of the above - all of the above _____ media contain an indicator that enables differences between microbes to be visualized.
- Differential
- Enriched
- Selective
- All of the above - differential Bacteria move by _____.
- flagella
- axial filaments
- slime secretions
- All of the above - all of the above _____ bacteria have flagella distributed all over the surface of the cell.
- Amphitrichous
- Monotrichous
- Peritrichous
- All of the above - peritrichous Motility media is a _____ used to detect bacterial movement.
- firm agar
- concentrated broth
- soft gel
- None of the above - soft gel _____ is a positive test result when using motility media.
- Flocculent growth
- Turbidity
- Clear media
- None of the above - turbidity ____ media contain agent(s) that prohibit the growth of some microbes.
- Differential
- Enriched
- Selective
- All of the above - selective
Very acidic or alkaline solutions compromise microbial respiration. True False - true _____ optimally grow at a pH between 8.0 and 11.5.
- Acidophiles
- Alkaliphiles
- Halophiles
- All of the above - alkaliphiles _____ solutions can lead to microbial cell swelling and rupture.
- Hypertonic
- Hypotonic
- Isotonic
- None of the above - hypotonic Microbes are only found growing at temperatures between 0°C and 100°C. True False - false Although oxygen is required for metabolism in many microbes, it is toxic to other species. True False - true _____ solutions can lead to cell shrinkage and eventual death.
- Hypertonic
- Hypotonic
- Isotonic
- None of the above - hypertonic _____ are microbes that require a high salt concentration for growth.
- Acidophiles
- Alkaliphiles
- Halophiles
- None of the above - halophiles Most microbes prefer to grow in environments that are pH neutral and isotonic. True False - true A _____ broth after incubation is a positive result when testing for pH and salt tolerances of microbes.
- clear
- turbid or cloudy
- green-colored
- None of the above - turbid or cloudy _____ is added to nutrient broth to adjust it to pH 9.
- Distilled water
- NaOH
- HCl
- None of the above - NaOH A microbe that produces clear broths when tested at 7% and 15% NaCl is considered a halophile. True False - false A microbe that only produces turbid broths in pH tests at pH 7 is considered a(n) _____.
- acidophile
- alkaliphile
- neutrophile
- None of the above - neutrophile Condition caused by viruses, bacteria, parasites, and fungi - infectious disease condition passed from person to person - contagious disease disruption of the normal state that impairs bodily structure and function - disease substance that stimulates the production of antibodies - vaccine Infectious diseases are caused by microscopic agents called pathogens. True False - true A _____ is a non-moving object responsible for the indirect transmission of disease.
- fomite
- vaccine
- vector
- All of the above - fomite A _____ is an example of a fomite.
- doorknob
- tissue
- used needle
- All of the above - all of the above All vaccines contain killed microorganisms. True
pathogenic microbe responsible for the majority of reported foodborne illeness - salmonella rapid heating and cooling of a liquid to reduce microbial numbers - pasteurization pathogenic microbe present on improperly washed raw vegetables - listeria One is six Americans become ill from foodborne pathogens every year. True False - true _____ is a pathogenic bacteria associated with foodborne illness.
- Campylobacter
- Listeria
- Salmonella
- All of the above - all of the above Food may become contaminated by coming into contact with microbes in the _____.
- soil
- irrigation water
- digestive tract
- All of the above - all of the above Pasteurization reduces microbial numbers by rapidly heating then cooling a liquid. True False - true _____ is the transfer of bacteria from one food item to another.
- Cross contamination
- Intoxication
- Pasteurization
- All of the above - cross contamination Most microbes associated with food are harmful to humans. True False - false ____ is a cause of foodborne illness.
- Cross contamination
- Endotoxin exposure
- Improper hand washing
- All of the above - all of the above C. botulinum infections are associated with poor food handling and processing procedures. True
False - true _____ are used to maintain safety in packaged and prepared foods.
- Butchering standards
- Pasteurization procedures
- Product recalls
- All of the above - all of the above Colder temperatures reduce the reproductive rates of most microbes. True False - true Sterile swabs should be moistened with _____ before collecting microbes from the surface of food items.
- distilled water
- isopropyl alcohol
- undiluted bleach
- All of the above - distilled water Unwashed vegetables possess the same numbers of microbes than those washed with soap and water. True False - false Microbe numbers in milk increase the longer it is stored in the refrigerator. True False - true One dye is used to directly stain the bacterial cell or the background. Cell shape, size, and arrangement may be determined with simple staining techniques. - simple stain A type of simple stain; only the bacterial cell becomes colored, leaving the background or external environment clear and colorless - direct stain A type of simple stain; the cell is unstained and appears as a bright, often colorless object against a dark-stained environment. - negative stain Two or more dyes are used. Cell morphology can be described and identification of the structural components (composition of the cell wall and other cell features like flagella, capsules, or endospores) is possible. - differential stain Colored ions in a stain - chromophores contains positively charged chromophores - basic stain
is a bacteriostatic, narrow-spectrum antibiotic that targets DNA gyrase in some Gram- positive bacteria. - Novobiocin enzyme necessary for DNA replication - DNA gyrase causes inhibition of growth of cells, not death - bacteriostatic antibiotics causes each of cells - bactericidal are designed to identify various metabolic properties of different bacteria species. More importantly, these tests, in conjunction with taxonomy, can lead to the unambiguous identification of an organism. - biochemical tests an anaerobic metabolic process that produces lactic acid, acetic acid, ethanol, carbon dioxide and hydrogen gas. - mixed-acid fermentation test is designed to identify microbes that ferment glucose via the butanediol pathway - Voges-Proskauer test esults in metabolites (by-products) that include oxygen ions and peroxides. These metabolites are chemically reactive and can cause damage to cell structures. - aerobic respiration Bacteria that live in oxygenated environments produce the enzyme ________ to neutralize the harmful effects of hydrogen peroxide. - catalase anaerobic microbes generally lack what enzyme - catalase is the conversion of pyruvic acid (the by-product of glycolysis), into an acid with or without the production of gas. - fermentation is a simple carbohydrate found in fruits and vegetables. - fructose is a simple carbohydrate produced by plant photosynthesis and from the metabolism of glycogen in animals - glucose is crystalline alcohol produced by many plants. - mannitol is commonly used as a pH indicator in carbohydrate fermentation tests. - Phenol red- turns yellow in acidic solutions are often used to determine the identity of unknown microbes, and come in several forms. See Figure 1. Three of the primary forms are selective, differential, and enriched.
contain agent(s) that prohibit the growth of some organisms, thus selecting or allowing the growth of other organisms. - selective media enable many types of microbes to grow; however, differential media contain an indicator that enables differences between microbes to be visualized. - differential media are supplemented with essential growth factors for organisms that do not grow well on typical media. - enriched media self-propelled motion - motility Bacteria cells with a single flagellum are termed - monotrichous single flagellum at each end are called - amphitrichous bacteria with numbers flagella at one end are described as what - lophotrichous flagella distributed all over the cell are called what - peritrichous microorganisms that grow best in a pH of 7 and maintaining a pH in their cytoplasm between 6.8 and 7.4 - neutrophiles optimally grow in pH between o and 5.5 - acidophiles optimally grow at pH between 8.0 and 11.5 - alkaliphiles refers to the concentration of solutes within a solution. - osmolarity require high salt concentration fro growth - halophiles occurs when a pathogen is passed immediately from one person to another via direct contact, such as a hand shake or by kissing. - direct transmission
- the pathogen is transferred to a fomite, a non-moving object such as a doorknob, tissue, or used needle. ● The pathogen becomes airborne via water droplets produced by coughing or sneezing. ● The pathogen is transported by a vector, a living organism such as a mosquito, fly, or tick. - indirect transmission is a substance that stimulates the immune system to produce antibodies; proteins that identify and neutralize pathogens and other foreign threats. - vaccine contains microorganisms that have been destroyed (killed) - killed vaccine
