WorksheetsMicrobiology Basics and Bacterial Cell Morphology
Total questions: 91
Worksheet time: 46mins
According to the section on Microbiology Basics, why is understanding the characteristics of bacteria, fungi, and viruses important for a veterinary technician?
It aids in collection, handling, and evaluation of samples
It eliminates the need for sterile technique
It ensures all pathogens are visible without staining
It replaces the need for laboratory equipment
Bacterial cells are described as prokaryotic in this section. Which statement best captures what that means for their internal structure?
They have no nucleus and most cellular organelles are absent
They have a true nucleus and abundant membrane-bound organelles
They have a nucleus but lack mitochondria only
They possess chloroplasts for photosynthesis
What size range is given for bacterial cells in this material?
0.02 to 0.2 μm
0.2 to 2.0 μm
2.0 to 20 μm
20 to 200 μm
Which surface features are noted as often present on bacteria in this section?
Capsules
Flagella
Cilia
Cell walls made of cellulose
Match each factor to its role in handling bacterial samples as described in the section.
Temperature requirements
Considered when collecting and preparing samples
pH requirements
Considered when collecting and preparing samples
Oxygen tension requirements
Considered when collecting and preparing samples
Nutritional requirements
Used to help identify samples
Which statement aligns with how environmental and nutritional requirements are used in practice with bacteria, according to the section?
They are irrelevant to sample preparation
They should be considered during collection and preparation and can help identify samples
They only matter after cultures have been fully identified
They apply exclusively to fungi and viruses, not bacteria
When preparing to collect a diagnostic specimen, which combination of tasks from the section should a veterinary technician directly apply?
Plan for proper collection technique
Handle the sample appropriately
Perform evaluation of samples
Skip pH considerations because bacteria are prokaryotic
Which characteristic listed in the section distinguishes bacteria from eukaryotic microorganisms?
Presence of a nucleus
Absence of most cellular organelles
Ability to photosynthesize like plants
Size greater than 20 μm
Which statement best describes obligate aerobes in terms of oxygen use?
They require oxygen for growth
They grow only in the absence of oxygen
They prefer reduced oxygen but can tolerate some
They require high levels of carbon dioxide
A bacterium is inhibited or killed when oxygen is present. Which category fits this organism?
Facultative anaerobe
Obligate aerobe
Obligate anaerobe
Microaerophilic
Facultative anaerobes are best characterized by which growth pattern relative to oxygen?
They cannot survive in oxygen at all
They can survive in oxygen but show limited growth
They require reduced oxygen and grow poorly at normal levels
They require high carbon dioxide and no oxygen
Microaerophilic bacteria differ from obligate aerobes because microaerophiles:
Require complete absence of oxygen
Prefer reduced oxygen levels
Require high carbon dioxide levels
Grow best at temperatures above 104°F
Capnophilic organisms are notable for which environmental requirement?
High levels of carbon dioxide
Absence of oxygen
Reduced oxygen with moderate carbon dioxide
Low pH below 5
Match each oxygen-related category to its defining condition.
Obligate aerobe
Requires oxygen
Obligate anaerobe
Growth inhibited or killed by oxygen
Microaerophilic
Prefers reduced oxygen
Capnophilic
Requires high carbon dioxide
Most bacteria live within which pH range?
5.0 to 6.0
6.5 to 7.5
7.5 to 8.5
8.5 to 9.5
Fastidious microbes are distinguished primarily by their:
Tolerance to high temperatures
Strict nutritional requirements
Ability to grow without oxygen
Preference for low pH
Which temperature category includes almost all pathogenic bacteria in animals, with optimal growth at 68–104°F?
Psychrophiles
Thermophiles
Mesophiles
Capnophiles
Psychrophiles are best described as bacteria that:
Grow optimally at higher temperatures
Grow best at lower temperatures
Require reduced oxygen
Need high carbon dioxide
Thermophiles differ from mesophiles because thermophiles:
Prefer lower temperatures
Prefer higher temperatures
Prefer reduced oxygen
Require high carbon dioxide
Select all categories that relate specifically to oxygen or gas composition requirements.
Obligate aerobe
Facultative anaerobe
Microaerophilic
Capnophilic
Mesophiles
Select the set of categories that are defined by temperature preferences.
Mesophiles, Psychrophiles, Thermophiles
Obligate aerobes, Obligate anaerobes, Microaerophilic
Capnophilic, Facultative anaerobes, Obligate aerobes
Fastidious microbes, Mesophiles, Capnophilic
A clinical isolate grows weakly in normal atmospheric oxygen but better when oxygen is reduced. Which classification is most appropriate?
Obligate aerobe
Obligate anaerobe
Microaerophilic
Thermophile
Refer to the diagram showing bacterial cell shapes labeled bacilli, cocci, and spirals. Which term describes spherical bacteria?
Bacilli
Cocci
Spirals
Palisades
In bacterial morphology, which arrangement depicts round cells grouped in grape-like clusters?
Chains
Clusters
Pairs
Tetrads
Match each bacterial arrangement to its description.
Chains
Linear sequence of cells end-to-end
Pairs
Two cells attached side-by-side
Tetrads
Group of four cells in a square
Palisades
Rod-shaped cells aligned like fences
Which statement best characterizes bacilli in the morphology figure?
They are spherical cells forming tetrads.
They are rod-shaped cells.
They are spiral-shaped cells with multiple turns.
They are oval cells always in pairs.
Which property is emphasized in the spores slide: endospores are resistant to which combination of stressors?
Heat
Desiccation
Chemicals
Radiation
Low pH only
According to the spores slide, endospore formation is characteristic of which genera when cultured?
Escherichia and Salmonella
Staphylococcus and Streptococcus
Bacillus and Clostridium
Mycobacterium and Neisseria
In the endospore diagram, the green spheres appear at different positions within a rod. What does this depict?
Binary fission stages
Flagellar arrangements
Endospore positions within a bacterial cell
Formation of capsules
Which statement about bacterial genetic organization and reproduction is shown on the growth slide?
They contain multiple linear chromosomes and divide by mitosis.
They contain a single DNA strand and reproduce primarily by binary fission.
They contain segmented RNA genomes and bud like yeasts.
They contain circular plasmids only and replicate by meiosis.
Place the four bacterial growth phases in logical order from first to last.
Initial/lag
1st
Exponential
2nd
Stationary
3rd
Death
4th
During the exponential phase described on the slide, which condition halts rapid growth?
Nutrients become depleted
Waste products accumulate
Space becomes limited
DNA mutates once
Binary fission ceases for genetic reasons
Which description best fits the stationary phase of bacterial growth?
Rapid doubling continues due to abundant nutrients.
Cells adapt to new media with little net change.
Population shows no net increase or decrease.
Cells die faster than they divide.
What distinguishes the lag phase from the death phase in the four-phase model?
Lag involves adaptation to new media; death involves decline in viable cells.
Lag is the period of maximal doubling; death is adaptation.
Lag shows no change while death shows exponential growth.
Lag and death both indicate rapid binary fission.
Based on the description, which statement best characterizes how fungi obtain nutrients?
They synthesize sugars internally through photosynthesis.
They absorb preformed organic molecules after external enzymatic digestion.
They fix atmospheric nitrogen directly into amino acids.
They ingest food particles via phagocytosis like many protists.
Identify the correct pairing of fungal terms with their definitions.
Mycelium
A large network formed by many slender tubes
Hyphae
Individual slender tubes that compose the network
Saprophytic
Obtains nutrients by decomposing dead organic matter
Parasitic
Obtains nutrients by living on and harming a host
Which statements about fungal structure and growth are accurate? Select all that apply.
Most fungi are multicellular, but yeast is an exception.
Hyphae form large webs that grow toward food sources.
Fungi grow toward light sources to enhance photosynthesis.
Hyphae are thick, flat tissues specialized for internal digestion.
According to the diagram showing hyphae secreting enzymes into soil, what is the immediate role of those enzymes?
To catalyze hydrolysis reactions that break down nutrients externally
To transport absorbed nutrients from soil directly into spores
To increase the temperature around hyphae for faster metabolism
To assemble nutrients into mycelium before absorption
Which statement about fungal reproduction is correct?
Yeasts reproduce primarily by budding.
Yeasts are multicellular and reproduce by binary fission.
All fungi reproduce only sexually via spores.
Yeasts reproduce by photosynthetic fragmentation.
According to the virology overview, which statement best describes how serologic testing confirms a recent viral infection?
A single high antibody titer measured at any time confirms recent infection.
Paired serum samples collected 2–3 weeks apart showing a rising antibody titer indicate recent infection.
A declining antibody titer in a single sample proves acute infection.
Serologic testing is only valid when performed in non-specialized laboratories.
Most viral diagnostic testing is conducted in which type of facility, based on the virology overview?
Primary care clinics
Home testing environments
Specialized laboratories
General hospital wards
Which practice aligns with recommended use of serologic tests for diagnosing viral diseases? Select all that apply.
Collect paired serum samples 2–3 weeks apart.
Interpret a rising antibody titer as evidence of recent infection.
Rely exclusively on clinical signs without laboratory testing.
Use a single baseline titer to definitively diagnose an acute infection.
In cell culture, what fundamental requirement is necessary for viruses to grow and replicate in the laboratory?
Nutrient-rich acellular media alone
Living cells to support viral replication
Antibiotics to stimulate viral division
High oxygen tension without cells
Which statement accurately describes the role of animal cells in vitro for viral diagnostics?
Animal cells are avoided because viruses only grow in bacterial cultures.
Animal cells grown in vitro are used to grow the viral sample.
Animal cells in vitro are used to measure antibody titers directly.
Animal cells are only necessary for bacterial pathogens, not viruses.
Match the diagnostic approach to what it can typically determine about a viral pathogen.
Clinical signs
Suggest family-level identification, sometimes genus/species
Cell culture
Grow virus in living cells for observation
Serologic procedures
Provide definitive identification via antibodies
Molecular testing (PCR)
Detect and identify pathogen using nucleic acids
Which statement best differentiates preliminary identification from definitive identification of a virus?
Clinical signs and cell culture alone provide definitive species-level ID.
Definitive identification generally requires serologic procedures, while clinical signs and cell culture may identify to family and possibly genus/species.
Molecular testing cannot be used for pathogen identification.
In-house tests replace the need for serology in all cases.
Which options correctly describe available diagnostic tools mentioned for viral pathogens? Select all that apply.
Some in-house tests exist for certain viral pathogens.
PCR is used as a molecular method to identify pathogens.
Only serologic testing is available; molecular methods are not used.
Cell culture is irrelevant for identifying viruses to any taxonomic level.
According to the guidelines for an in-house microbiology laboratory, which feature best supports effective decontamination of work surfaces?
Carpeted flooring to absorb spills
Textured benches that increase friction
Smooth surfaces that are easily disinfected
Wooden countertops that resist heat
Which statement most accurately describes the recommended location of an in-house microbiology laboratory relative to the facility?
Adjacent to the main traffic corridor for easy access
Integrated into the reception area to monitor visitors
Ideally in a separate room away from the main traffic areas
On an outdoor patio to maximize ventilation
Select all design elements that are recommended for the physical setup of an in-house microbiology laboratory.
Adequate lighting and ventilation
A washable floor
Multiple entry points to encourage traffic
Electrical outlets
Ample storage
In the recommended layout, the lab should have at least two work areas. Which pairing reflects the intended separation of tasks?
Microscopy and sterilization
Processing and culture work
Training and administrative work
Waste disposal and delivery
Which action is specifically prescribed for managing a spill of microbial culture in the lab?
Wipe immediately with dry paper towels
Apply disinfectant and allow a 20-minute contact time
Cover with sand to absorb liquid
Move the spill to the sink for dilution
Which practices align with laboratory safety expectations when working with potentially pathogenic and/or zoonotic organisms? Select all that apply.
Use aseptic technique
Wear appropriate personal protective equipment
Eat and drink at the bench to maintain hydration
Wash hands
Report accidents promptly
For biological waste and used cultures, what disposal approach is indicated by the safety guidance?
Flush all cultures down the drain with hot water
Autoclave or dispose of properly according to protocol
Store indefinitely in cold storage to prevent growth
Burn openly in a fume hood
Which personal grooming or conduct recommendation is part of the lab safety rules?
Wear perfume to mask odors
Handle contact lenses only after donning gloves
Keep hair pulled back and avoid eating, drinking, or applying cosmetics
Trim nails at the bench during downtime
Which item is explicitly listed as essential for maintaining controlled growth conditions during microbiology procedures?
A good-quality incubator
Wooden tongue depressors
Rayon swabs in transport media
Discard jar—disinfectant
Select all items that are identified as collection and preparation supplies for microbiology work.
Sterile cotton-tipped swabs
Dull scalpel blades
Antibiotic discs and dispensers
High-quality glass slides and coverslips
Which pairing correctly matches a volume range of syringes with the gauge range of needles specified?
3- to 20-mL syringes with 21- to 25-g needles
1- to 5-mL syringes with 18- to 20-g needles
10- to 50-mL syringes with 14- to 16-g needles
2- to 10-mL syringes with 25- to 30-g needles
Which device is indicated for airway or urinary sampling in the supplies list?
Sterile endotracheal tube or jugular or urinary catheter
Bunsen burner or alcohol lamp
Candle jar or anaerobe jar
Racks for tubes
Which item is specified for transporting swab specimens?
Rayon swabs in transport media
Inoculating loops—reusable metal
Gram stain reagents
Polystyrene shipping containers
Which items are named for specimen preservation and initial handling?
Collection tubes and preservatives
Sterile cotton-tipped swabs
Variety of culture media
Scissors, forceps
Match each tool to its primary use category based on the list.
Inoculating loops or wires
Transfer of cultures
Bunsen burner or alcohol lamp
Heat/flame source
Antibiotic discs and dispensers
Antimicrobial susceptibility testing
Racks for tubes
Organization/holding of tubes
Which item provides an environment suitable for anaerobic growth according to the list?
Candle jar or anaerobe jar
Refrigerator—cold packs
Wooden tongue depressors
High-quality glass slides
Select the items that are explicitly identified as culture media or support for culturing organisms.
Variety of culture media
Inoculating loops or wires—reusable metal or disposable plastic
Gram stains and other stains
Antibiotic discs and dispensers
Which staining category is explicitly named among the supplies?
Gram stains and other stains
Acid-fast stains only
Simple methylene blue stain only
No stains listed
Which items are indicated for cutting or grasping during procedures?
Scissors
Forceps
Wooden tongue depressors
Racks for tubes
Which item in the list is intended for safe disposal by containing disinfectant?
Discard jar—disinfectant
Refrigerator—cold packs
Candle jar
Endotracheal tube
Which pair of materials is specified for slide preparation?
High-quality glass slides and coverslips
Plastic Petri dishes and lids
Aluminum plates and foils
Paper cards and tape
Which item offers a flame needed for sterilizing tools like loops?
Bunsen burner or alcohol lamp
Candle jar or anaerobe jar
Antibiotic discs and dispensers
Wooden tongue depressors
Select the items listed that are part of refrigeration and transport logistics.
Refrigerator—cold packs
Polystyrene shipping containers
Variety of culture media
Scissors, forceps
Match each collection supply to its typical application.
Sterile cotton-tipped swabs
Surface or mucosal sampling
Dull scalpel blades
Tissue scraping when sharpness is not required
Sterile endotracheal tube
Airway sampling
Jugular or urinary catheter
Blood or urine collection pathway
Which item is explicitly listed as a wooden tool used in microbiology procedures?
Wooden tongue depressors
Plastic inoculating loops
Glass slides
Metal forceps
Which items are identified as either reusable metal or disposable plastic according to the list?
Inoculating loops or wires
Scissors and forceps
Antibiotic discs
Collection tubes
Which statement best defines culture media used in microbiology?
A nutrient material, solid or liquid, that supports microorganism growth
Any sterile container used to hold microbial samples
Only solid materials that inhibit microbial growth
A chemical that kills all microorganisms
Identify the source of agar as a solidifying agent for culture media.
Protein derived from animal tissues
Mineral salts extracted from soil
Dried extract of sea algae
Synthetic polymer produced in a lab
Which statements about common solidifying agents are correct? Select all that apply.
Agar is a dried extract of sea algae
Gelatin is a protein obtained from animal tissues
Agar and gelatin are both antibacterial
Gelatin is a carbohydrate from plants
At what temperature range should culture media be stored according to the guidance?
68–77 °F (room temperature)
41–50 °F (refrigerated)
20–25 °C (ambient lab)
32–40 °F (freezer)
Match each type of media with its primary purpose.
Transport media
Keep microbes alive without encouraging growth
General purpose media
Support broad, non-fastidious microbial growth
Enriched media
Meet requirements of fastidious pathogens
Selective media
Contain antibacterial substances to suppress all but a few types
Differential media
Enable grouping by biochemical reactions
Which description best characterizes enrichment (liquid) media?
Used to keep microbes alive but not growing
Contain dyes to indicate biochemical reactions
Favor growth of a particular group or organism
Contain antibacterial substances to kill most bacteria
Some media can serve more than one function. Which combination is plausible based on the descriptions provided?
Selective and differential in the same formulation
Transport and enriched simultaneously
General purpose and transport simultaneously
Selective and enrichment (liquid) simultaneously
Which media type would you choose to initially maintain a specimen’s viability during transit without promoting proliferation?
General purpose media
Differential media
Transport media
Enriched media
Blood agar is described as both enrichment and differential media. Which property primarily makes it differential?
Presence of sheep blood that supports fastidious growth
Ability to detect and distinguish hemolysis patterns around colonies
Inhibition of Gram-negative bacteria by bile salts
Incorporation of crystal violet to prevent swarming
On blood agar, which hemolysis type is characterized by a clear zone surrounding the colony due to complete lysis of red blood cells?
Alpha hemolysis
Beta hemolysis
Gamma hemolysis
Delta hemolysis
Which description correctly matches alpha hemolysis observed on blood agar?
No change in the appearance of the medium around colonies
Partial hemolysis with a greenish or slimy discoloration around colonies
Complete hemolysis producing a transparent zone around colonies
Double zone hemolysis with two concentric rings
Identify the hemolysis type that produces no visible change in the medium on blood agar.
Alpha hemolysis
Beta hemolysis
Gamma hemolysis
Delta hemolysis
Which statement best describes delta hemolysis on blood agar?
A double zone of hemolysis is present
A greenish discoloration indicates partial hemolysis
A clear halo indicates complete hemolysis
No visible change occurs in the medium
MacConkey agar is formulated to be selective and differential. Which components primarily confer selectivity?
Sheep blood and lactose
Crystal violet and bile salts
Neutral red and peptone
Glucose and sodium chloride
Which organisms are most inhibited by MacConkey agar due to its selective agents?
Gram-positive bacteria
Gram-negative bacteria
Acid-fast bacteria
Anaerobic bacteria
On MacConkey agar, lactose fermentation is detected by colony color. Which interpretation is correct?
Lactose fermenters produce colorless colonies due to lack of acid production
Non-lactose fermenters produce pink colonies because they lower pH
Lactose fermenters produce pink colonies by acidifying the medium
All colonies remain colorless because the dye is inhibitory
Which pairing correctly matches media type to its primary differential feature?
Blood agar
Hemolysis patterns (alpha, beta, gamma, delta)
MacConkey agar
Lactose fermentation indicated by colony color
Blood agar (delta)
Double-zone hemolysis visible around colonies
A clinical sample is streaked on blood agar and MacConkey agar. Colonies show a clear zone on blood agar and colorless colonies on MacConkey. Which interpretation is most consistent?
The organism causes complete hemolysis (beta)
The organism is a lactose fermenter
The organism is inhibited by crystal violet and bile salts
The organism is a non-lactose fermenter
