Exam 1 Microbiology
- What are the factors that are related to effective disinfection?
- concentration of disinfectant, organic matter, pH, and time
Figure 6.1, which line best depicts a facultative anaerobe in the absence of O2? a b c
b
In Figure 6.3, which tube shows the expected growth pattern for a facultative anaerobe? a b c d e
b
Which statement best describes what happens when a gram-negative bacterium is placed in distilled water and penicillin? a) No change will result; the solution is isotonic b) Water will move into the cell c) Water will move out of the cell d) the cell will undergo osmotic lysis e) Sucrose will move into the cell from an area of higher concentration to one of lower concentration
b) Water will move into the cell
Which of the following types of radiation is the LEAST effective control method against microorganisms? a. Gamma rays b. Microwaves c. X rays d. UV light
b. Microwaves
You have isolated a cell with a peptidoglycan cell wall. What other structure can you safely assume the cell has? a. a nucleus b. a plasma membrane c. a mitochondrion d. a chloroplast
b. a plasma membrane
A medium containing chemicals to inhibit the growth of gram-positive bacteria would be called __________. a. enriched b. selective c. reduced d. differential
b. selective
A medium containing lauryl sulfate inhibits the growth of gram-positive bacteria. This medium is __________. a. differential b. selective c. enriched d. reduced
b. selective
An antiseptic is used to remove microbes from __________. a. foods before canning them b. skin before an injection c. restaurant glassware d. toilet surfaces e. food preparation areas
b. skin before an injection
Salt agar tends to inhibit the growth of most organisms, except Staphylococci. This is an example of a(n) __________ medium. a. enriched b. all-purpose c. selective d. differential
c. selective
Consider a culture medium on which only gram-positive organisms such as Staphylococcus aureus colonies can grow due to an elevated NaCl level. A yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the pH as a result and changing the color of a pH indicator chemical. This type of medium would be referred to as a(n) a. differential and enrichment culture. b. selective medium. c. selective and differential medium. d. differential medium. e. enrichment culture.
c. selective and differential medium.
In a _________, cells are added to melted agar and poured into a Petri dish.
pour plate
A student has obtained a sample of pond water for study. Using the high-power lens, he observes several cells with nuclei. He can conclude that the cells are NOT bacteria: - true or false
true
Adding salts to a solution increases osmotic pressure and is used to preserve food. true or false
true
Agar is used as a solidifying agent in microbiological media since few bacteria can degrade it. true or false
true
An isolated colony on a streak plate contains millions (or even billions) of identical cells all arising from one initial cell. true or false
true
An unknown organism grows at the top of a tube of thioglycolate broth. This organism is best described as an obligate aerobe for its oxygen requirements. true or false
true
Anton van Leeuwenhoek was the first to observe microbes: - true or false
true
Autoclaving is the most effective method of moist heat sterilization. true or false
true
Bacterial growth refers to an increase in the numbers of cells in a bacterial culture. true or false
true
Bacterial smears should be fixed to the slide before all staining procedures. true or false
true
Both phase-contrast microscopy and differential interference contrast microscopy are used to view the internal structures of cells without staining. true of false
true
Cells viewed in darkfield microscopy appear similar to those stained with the negative stain. true or false
true
Ethylene oxide gas is used to sterilize medical equipment that might be damaged by exposure to the heat of autoclaving. true or false
true
Biofilms are commonly found in which of the following environments? a. a rock in a lake b. teeth c. water pipes d. medical devices e. all of the above
e. all of the above
Microbes are responsible for __________. a. breaking down wastes b. oxygen generation via photosynthesis c. synthesis of vitamins d. synthesis of acetone and alcohol e. all of the above
e. all of the above
Pure cultures can easily be obtained on streak plates, even if the desired bacteria are present in very low concentrations in the initial culture broth. true of false
false
Soap is ineffective in killing bacteria. Therefore, handwashing is a rather ineffective measure in preventing disease transmission. true or false
false
Some viruses can contain both DNA and RNA: - true or false
false
The capsules and flagella of bacteria can be observed in gram-stained smears. true or false
false
The greater resolution of the electron microscope compared to the compound microscope is due to the longer wavelengths of the electrons used to examine specimens. true or false
false
The pH of the medium has no effect on the activity of the disinfectant being applied. true or false
false
The process of pasteurization to reduce food spoilage utilizes high heat to kill all bacteria present: - true or false
false
The vast majority of bacteria are harmful to humans or plants: - true or false
false
Ultraviolet light (UV) causes irreversible breaks in DNA strands. true or false
false
Filtration methods, followed by growth of the bacteria trapped on the filters in growth media, are used to count bacteria present in very low concentrations, such as in lakes and streams. true or false
true
Flagella are appendages that allow locomotion in bacteria: - true and false
true
Flagella are too small to be seen with the light microscope when stained by the Gram stain protocol. true or false
true
If you observe rod-shaped red cells after the Gram stain, you can assume their cell walls contain endotoxin. true or false
true
Immersion oil acts to decrease refraction of light rays and thus increase resolution. true or false
true
In a completed Gram stain, gram-positive bacteria are purple. true or false
true
Laboratory cultivation of obligate anaerobes requires reducing media or special growth chambers filled with inert gases. true or false
true
Microbes are associated with life-sustaining benefits as well as life-threatening diseases: - true or false
true
Moist heat destroys organisms by denaturing proteins. true or false
true
Nitrogen-fixing bacteria, such as cyanobacteria, can use atmospheric nitrogen (N2) for their nitrogen source. true or false
true
Pseudomonas has been found growing in quaternary ammonium compounds (quats). true or false
true
Psychrotrophic organisms are often responsible for food spoilage in refrigerated foods. true or false
true
Scanned probe microscopy is used to examine fine detail of molecular complexes, such as blood clots, or molecules, such as DNA. true or false
true
Small, hydrophobic molecules pass through a cell membrane most easily by diffusion. true of false
true
Some antimicrobial chemicals are considered to be disinfectants and antiseptics. true or false
true
Spheroplasts, protoplasts, and mycoplasms are bacterial cells without cell walls. true or false
true
The Gram stain is important in medical microbiology because the results help physicians select appropriate antibiotics for treatment. true or false
true
The cell membrane is a fluid structure that allows membrane proteins to move freely. true or false
true
The cell walls of bacteria are responsible for the shape of the bacteria and the difference in the Gram stain reaction. true of false
true
The counterstain used in the Gram stain is a basic dye. true or false
true
The internal structure of eukaryotic cilia and flagella are the same. true or false
true
The limit of resolution of the compound microscope illuminated with visible light is approximately 0.2 μm. true or false
true
The plane in which a bacterial cell divides determines the arrangement of cells. true or false
true
The presence of organic matter, such as blood or saliva, may impair the action of antimicrobial chemicals. true or false
true
The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature. true or false
true
Turbidity is an indirect measurement of bacterial growth that can be measured using a spectrophotometer. true or false
true
Vaccines were invented by Alexander Fleming in 1920: - true or false
true
The Nucleus: * double membrane structure (___________) that contains the cell's DNA. * DNA is complexed with _______ proteins to form _________. * during mitosis and meiosis, chromatin condenses into ________.
* (nuclear envelope) * histone/ chromatin * chromosomes
Fimbriae and Pili: - Fimbriae: * hairlike appendages that allow for ________. * ________ than pili. - Pili: * involved in _____ (______ and _______ motions) * ________ involved in DNA transfer from one cell to another.
* attachment * shorter * motility (gliding and twitching) * conjugation pili
Comparing Prokaryotic and Eukaryotic Cells: - Prokaryote: * one _______ chromosome, not in a _________. * no ______ or _______. * include _____ and ______. * bacteria: _______ cells walls * archaea: ______ cell walls * divides by ________. - Eukaryote: * _______ chromosomes, in __________. * has _______ and _______. * ________ cell walls, when present. * divides by _______ for what three things?
* circular/ membrane * histones or organelles * bacteria and archaea * peptidoglycan * pseudomurein * binary fission * paired linear/ nuclear membrane * histones and organelles * polysaccharide * mitosis/ growth, repair, and replace
Compound Light Microscopy: - Brightfield illumination * _______ objects are visible against a _______ background. * Light reflected off the specimen does not enter the _______ lens. - In a compound microscope the image is _______ and ______ from the actual sample you are looking at.
* dark/ light * objective - reversed and backwards
Composition and Characteristics: - Peptidoglycan: * polymer of a repeating ______ in rows: _____ and ______. * rows are linked by _______.
* disaccharide/ NAG and NAM * polypeptides
A disk-diffusion test using Staphylococcus gave the following results: Disinfectant/Zone of inhibition (mm) - A/0 - B/2.5 - C/10 - D/5 * In the table, which compound was bactericidal? a. A b. B c. C d. D e. The answer cannot be determined based on the information provided. * In Table 7.1, which compound was the most effective against Staphylococcus? a. A b. B c. C d. D e. The answer cannot be determined based on the information provided. * In Table 7.1, which compound was the most effective against E. coli? a. A b. B c. C d. D e. The answer cannot be determined based on the information provided.
* e. The answer cannot be determined based on the information provided. * c. C * e. The answer cannot be determined based on the information provided.
Atypical Cell Walls: - Acid-fast cell walls: * like _________ cell walls * include _____ and ______ * stain with _________ * _______ (______) bound to peptidoglycan = this interferes with gram staining! - Myoplasmas: * lack _______ (need a controlled environment because it is susceptible to _____________) * ______ in plasma membrane - Archaea: * ______ or * walls of _______ (lack NAM and D-amino acids).
* gram-positive * mycobacterium and nocardia * carbolfuchsin * waxy lipid (mycolic acid) * cell walls/ (osmotic pressure changes) * sterols * wallless * pseudomurein
- Scientific names: * are ______ or _________ * the ______ is capitalized and the ________ is lowercase. * are ________ and used worldwide * may be ________ or honor a scientist - Escherichia coli: * honors the discoverer, ___________ * describes the bacterium's habitat - ____________ - Staphylococcus aureus * describes the ________ (staphylo-) __________ (coccus) cells * describes the _________ (aureus) colonies * this is normal biota of the ___________. - What is the study of shapes?
* italicized or underlined * genus/ specific epithet * latinized * descriptive * Theodor Escherich * large intestine or colon * clustered/ spherical * gold-colored * respiratory system - morphology
Gram-Positive Cell Walls: - Teichoic acids: * _______ links cell wall to plasma membrane. * wall ________ links the peptidoglycan. * carry a _______ charge (due to acid) * regulate movements of ______. - _______ and ________ provide antigenic specificity. - What gives gram-positive bacteria strength and rigidity? - What does penicillin target in gram-positive bacteria?
* lipoteichoic acid * teichoic acid * negative * cations - polysaccharides and teichoic acids - carbohydrate backbone - the enzyme that forms the bond between protein and carbohydrate cross-linkage.
Three Domains: - Bacteria: * no ________ or ________. * _________ cell walls * 1 _____ polymer * F-methionine * _________ rare * no __________ * ________ chromosomes - Archaea: * no ______ or _______ * no peptidoglycan/ several polymers/ methionine/ introns present * has ________ * _______ chromosomes - Eukarya: * has a ______ and _______ * no peptidoglycan/ several polymers/ methionine/ introns are common. * has ________ * ______ chromosomes
* nucleus or organelles * peptidoglycan * RNA * introns * histamines * circular * nucleus or organelles * histamines * circular * nucleus or organelles * histamines * linear
The Plasma (cytoplasmic) Membrane: - Compare and contrast prokaryotic and eukaryotic plasma membranes: * Similar in structure to prokaryotic cell membranes include: ________ and ________. * Differences in structure: ______ - complex lipids and ________ for attachment and cell-to-cell recognition. *Similar functions include: __________ and all _______/_______ processes. * Differences in function: - __________: phagocytosis and pinocytosis. - __________: pseudopods extend and engulf particles. - __________: membrane folds inward, bringing in fluid and dissolved substances.
* phospholipid bilayer and internal/peripheral proteins * sterols/ carbohydrates * selective permeability and passive/active * endocytosis/ phagocytosis/ pinocytosis
The Cell Wall and Glycocalyx: - Cell Wall: * found in _______ (3) * made of ________ (_____ in plants, _______ in fungi, and ________ in yeasts). - Glycocalyx: * found in _______ * _________ bonded to ________ and _______ in the plasma membrane.
* plants, algae, and fungi * carbohydrates (cellulose/ chitin/ glucan and mannan) * animal cells * carbohydrates/ proteins and lipids
- E. coli O157:H7: * _________ producing strain of E. coli. * first seen in 1982; causes ________ diarrhea (leading cause of diarrhea worldwide) ... death from dehydration. - Middle East Respiratory Syndrome (MERS): * caused by the Middle East respiratory syndrome ________ (MERS-CoV). * common to SARS: causes severe _____________. * 100 deaths in the Middle East from 2012 to 2014. - Avian Influenza A (H5N1) * Influenza A virus * primarily in _______ and _______ * sustained human-to-human transmission has not yet occurred. - Methicillin-Resistant Staphylococcus aureus (MRSA): * Is a type of ________. * 1950s: ________ resistance developed * 1980s: ________ resistance * 1990s: MRSA resistance to ________ reported (VISA = vancomycin-intermediate S. aureus/ VRSA = vancomycin-resistant S. aureus) - West Nile Encephalitis (WNE): * caused by the _______. * first diagnosed in the West Nile region of Uganda in 1937 * appeared in New York City in 1999 * transmitted between birds and to horses and humans by _______. - Bovine Spongiform Encephalopathy (________): * caused by a ________ (an infectious ________ that also causes _________) * new variant of CJD in humans is related to cattle that have been given feed made from prion-infected ________. - Ebola Hemorrhagic Fever (EHF): * Ebola ______ * causes fever, hemorrhaging and _________ * transmitted via contact with infected _____ or _______. * first identified near Ebola River, Congo * 2014 outbreak in Guinea, hundreds killed - Crytosporidiosis: * Crytosporidium ____________ * first reported in 1976 * causes 30% of ________ illness in developing countries. * in the United States, transmitted via _______. - AIDS (Acquired Immunodeficiency Syndrome): * caused by ___________. * first identified in 1981 * _______ affecting males and females * worldwide epidemic infecting 35 million people; 6000 new infections every day * HIV/AIDS in the United States: ____% are female, and ____% are African American
* shiga toxin * bloody * coronavirus * acute respiratory syndrome * waterfowl and poultry * bacteria (big deal in hospital settings) * penicillin * methicillin * vancomycin (last resort because of bad side effects = messes with liver) * West Nile virus * mosquitoes - mad cow * prion/ (mis-folded protein/ Creutzfeldt-Jakob disease (CJD) * sheep * virus * blood clotting * blood or body fluids * protozoa * diarrheal * water * human immunodeficiency virus (HIV) * STI * 26/ 49
- Knowledge of microorganisms allows human to: * prevent food __________ * prevent __________ * understand _______ and ________ of disease to prevent epidemics.
* spoilage * disease * causes and transmission
- Gram-Positive Cell Walls: * _______ peptidoglycan (___________) * ________ acids * _____ in basal body of flagella. * produce _______. * _____ susceptibility to penicillin * disrupted by ________. - Gram-Negative Cell Walls: * ______ peptidoglycan * ______ membrane (main difference) * _________ space * _______ in basal body of flagella * produce ______ and ______. * _____ susceptibility to penicillin. - _____% of bacteria fall into one of these groups.
* thick (outer layer) * teichoic * 2-rings * exotoxins * high * lysozyme * thin * outer * periplasmic * 4-rings * endotoxins and exotoxins * low - 99
The Microbiome: - The Human Microbiome Project (begun in 2007) * goal of determining the makeup of __________ of various areas of the body. * secondary goal of understanding relationship between changes in _______ and __________. - The National Microbiome Initiative (NMI, begun 2016) * explores the role microbes play in different _________.
* typical microbiota * microbiome and human diseases * ecosystems
Plasma Membrane Structure: - Fluid Mosaic Model: * membrane is as _________ as olive oil. * semipermeable and ________ (______ have a hard time passing) * _____ move freely for various functions. * _______ rotate and move laterally. * self-sealing and self-healing * surprisingly _________. * proteins receive ________ from the world outside or transport ________ and ________.
* viscous * selective/ (charged ions) * proteins * phospholipids * flexible (supple) * signal/ nutrients and wastes
Evolution of Eukaryotes: - Life arose as simple organisms _____ to _____ billion years ago. - First eukaryotes evolved _____ billion years ago. - Endosymbiotic Theory: * larger bacterial cells engulfed smaller bacterial cells, developing the first ___________. * ingested photosynthetic bacteria became ________. * ingested aerobic bacteria become _________.
- 3.5 to 4 - 2.5 * eukaryotes * chloroplasts * mitochondria
Plate Counts: - Count colonies on plates that have ____ to _____ colonies (CFUs). - To ensure the right number of colonies, the original inoculum must be diluted via ________ (in a line or series). THE MOST COMMON WAY TO DETERMINE # OF BACTERIA. - Counts are performed on bacteria mixed into a dish with agar (___________) or spread on the surface of a plate (___________). - Serial Dilution equation: ? * If there are 54 colonies on a plate of 1:100 dilution, then the count of bacteria/ml in sample is ________.
- 30 - 300 - serial dilution - (pour plate method)/ (spread plate method) - number of colonies on plate x reciprocal of dilution of sample = number of bacteria/ml * 5400
Preparing Smears for Staining: - Live and/or unstained specimens have little contrast with the surrounding medium (________ for the most part). Live specimens are used to study ________. - ________: coloring microorganisms with a dye that emphasizes certain structures. - _______: a thin film of a material containing microorganisms spread over a slide. - Microorganisms are _______(attached) to the slide, which kills the microorganisms.
- (transparent)/ cell behavior - staining - smear - fixed
Other Chemical Used for Sterilization: - Plasma: * ________ state of matter, consisting of electrically excited gas. * _________ destroy microbes * used for ____________. - Supercritical Fluids: * _______ with gaseous and liquid properties. * used for ____________ * demonstrates all _______ of matter. - Peroxygens and Other Forms of Oxygen: * ________ agents (what do they do with electrons?) * used for _________ and _________ * example
- * fourth * free radicals * tubular instruments - * CO2 * medical implants * 3 phases - * oxidizing (lose them) * contaminated surfaces and food packaging * O3 (ozone), H2O2, and peracetic acid
Chemical Requirements: - Carbon: * structural backbone of ________ molecules (forms 4 covalent bonds) * __________ use organic molecules as energy (humans) * _________ use CO2 as energy (photosynthesis) * what does -troph mean? - Nitrogen: * component of _________, ________, and _______. * most bacteria decompose _________ material for the nitrogen source. * some bacteria use NH4+ or NO3- from organic material. * a few bacteria use N2 in ______________ (which is what?) * what is the element that be breath in most? - Sulfur: * used in _________, _______, and _______. * most bacteria decompose ________ for the sulfur source. * some bacteria use SO4 2- or H2S. - Phosphorus: * used in ______, ______, and _______. * found in _________. * PO4 3- is a source of phosphorus. - Trace Elements: * _______ elements required in small amounts. * usually as enzyme _______. * include iron, copper, molybdenum, and zinc.
- * organic * chemoheterotrophs * autotrophs * to eat - * proteins, DNA, and ATP * protein * nitrogen fixation (take N2 and fix it into compounds they can use) * nitrogen (79%) - * amino acids, thiamine, and biotin * proteins - * DNA, RNA, and ATP * membranes - * inorganic * cofactors
Selective and Differential Media: - Selective: * _______ unwanted microbes and _______ desired microbes. * contain _________ to suppress growth. - Differential: * allow __________ of colonies of different microbes on the same plate. - What is an example of media that is selective and differential? EXPLAIN
- * suppress/ encourage (selective for certain organisms) * inhibitors - * distinguishing - mannitol salt agar. It is selective for halophiles (like salt) and is differential when phenol red is used. phenol red has a pH of 7, which gives it its red color. A drop in pH turns the phenol red to a yellow color (drop in pH because they can metabolize it).
- Cell in isotonic solution: Under these conditions, the solute concentration in cell is equivalent to a solute concentration of _________ (physiological saline). - Plasmolyzed cell in hypertonic solution: If the concentration of solutes such as NaCl is higher in the surrounding medium than in the cell, water tends to _______ the cell and growth of the cell is inhibited (what does not shrink?)
- 0.85% sodium chloride (NaCl) - leave/ (cell wall)
Physical Requirement: pH: - Most bacteria grow between a pH of ________ to _______. - Molds and yeasts grow between _______ and _____. - _________ grow in acidic environments. - Most living cells have a very ________ range of pH. - pH is __________ in all biological organisms. - Each pH unit represents a factor of ______ difference in pH. - pH results in ions, which create ___________.
- 6.5 - 7.5 - 5 - 6 - acidophiles - narrow - controlled - 10 - concentration gradients
- In Table 7.3, which disinfectant is the most effective at stopping bacterial growth? A) Doom B) K.O. C) Mortum D) Sterl E) The answer cannot be determined based on the information provided. - In Table 7.3, which disinfectant was bactericidal? A) Doom B) K.O. C) Mortum D) Sterl E) The answer cannot be determined based on the information provided. - In Table 7.3, which disinfectant was most effective against Salmonella? A) Doom B) K.O. C) Mortum D) Sterl E) The answer cannot be determined based on the information provided.
- A) Doom - C) Mortum - E) The answer cannot be determined based on the information provided.
A Fortunate Accident: Antibiotics: - 1928: ________ discovered the first antibiotic (by accident). - He observed that Penicillium fungus made an antibiotic, __________, that killed __________. * Explain what the fungus/antibiotic does to bacteria! - 1940s: this antibiotic was tested clinically and mass-produced. - Before antibiotics, what did doctors use to treat infections?
- Alexander Fleming - penicillin/ S. aureus * attacks/inhibits the cell wall of bacteria and has no hinder on our own cells (b/c we don't have cell walls). Fungus evolved as a way of survival. - bacteriophages (type of virus) = attack only the bacteria and leave our cells alone
A suspension of 106 Bacillus cereus endospores was put in a hot-air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown. - In Figure 7.1, what is the thermal death time? A) 150°C B) 60 minutes C) 120 minutes D) 100°C E) The answer cannot be determined based on the information provided. - In Figure 7.1, the thermal death point for this culture is A) 15 minutes. B) 50°C. C) 30 minutes. D) 170°C. E) The answer cannot be determined based on the information provided - In Figure 7.1, the decimal reduction time (D value) for the culture, which is defined as the time to reduce a population by one log, is approximately A) 0 minutes. B) 10 minutes. C) 30 minutes. D) 40 minutes. E) 60 minutes.
- B) 60 minutes - E) The answer cannot be determined based on the information provided - B) 10 minutes.
Biosafety Levels: - __________: no special precautions; basic teaching labs. - __________: lab coat, gloves, and eye protection. - __________: biosafety cabinets to prevent airborne transmission. - __________: sealed, negative pressure; "hot zone" * exhaust air is filtered twice through _________.
- BSL-1 - BSL-2 - BSL-3 - BSL-4 * HEPA filters
Bacterial Growth Curve: - Lag phase: ? - Log phase: ? - Stationary phase: ? - Death phase: ?
- Bacteria are metabolically very active, but the numbers are not increasing. - Period of most rapid growth. Number of bacteria is increasing exponentially. - Population growth has halted. Number of new cells formed balances the number of cells dying. - Rate of the cell death exceeds the rate at which new cells are being formed. Numbers of cells decline exponentially.
Recombinant DNA Technology cont.: - 1941: ________ and ________ showed that genes encode a cell's enzymes. - 1944: _________, ________, and _________ showed that DNA is the hereditary material. - 1953: ________ and _________ proposed a model of DNA structure. * __________: used her crystal structure to determine the 3D structure of DNA; however she is not credited. - 1961: _________ and _________ discovered the role of mRNA in protein synthesis.
- Beadle and Tatum - Avery, MacLeod, and McCarty - Watson and Crick * Rosalind Franklin - Jacob and Monod
Classification of Microorganisms: - Developed by __________ in 1977. - Three domains based on ___________. - What are the three domains? - What are the four subcategories (kingdoms) of eukarya? - Explain endosymbiosis! * mitochondria are related to __________. * chloroplasts are related to _________. **** MITOCHONDRIA CAN NOT GROW ON ITS OWN IF PULLED OUT OF CELLS BECAUSE ITS GENOME IS EVOLVING!
- Carl Woese - cellular organization (structure) - Bacteria (pro.), Archaea (pro.), and Eukarya (euk.) - protist (catch all), fungi, plants, and animals - mitochondria and chloroplasts have their own genome = used to be bacteria (divide by binary fission) and at some point became part of eukaryotic cells. * alpha-proteio bacteria * cyanobacteria
- ___________ established the system of scientific naming of organisms in 1735. * naming known as __________. * He is known as the ____________. - Each organism has _____ names: * the _______ (first) * the _______ or ________ (last) - This allows us to show that there is a relationship between all living things. - What is the order of naming (going from broad to more specific)
- Carolus Linnaeus * binomial nomenclature * father of modern taxonomy - two * genus * specific epithet or species - domain -> kingdom -> phylum -> class -> order -> family -> genus -> species
Vaccination: - 1796: _________ inoculated a person with cowpox virus, who was then immune from _________ (first person to vaccinate a person and exposed him to the actual disease). - Vaccination is derived from the Latin word vacca, meaning _____. - This protection is called _______. - 1717: _________: did work in vaccination by exposing people to active forms of the cowpox virus (variolation - similar to vaccination).
- Edward Jenner/ smallpox - cow - immunity - Lady Mary Montagu
- Who developed a vaccine against smallpox? - Who discovered how DNA controls protein synthesis in a cell? - Who discovered penicillin? - Who discovered that DNA can be transferred from one bacterium to another? - Who disproved spontaneous generation? - Who was the first to characterize a virus? - Who was the first to use disinfectants in surgical procedures? - Who was the first to observe bacteria? - Who was the first to observe cells in plant material and name them? - Who observed that viruses are filterable material? - Who proved that DNA is the hereditary material? - Who proved that microorganisms can cause disease? - Who said living cells arise from preexisting living cells? - Who showed that genes code for enzymes? - Who spliced animal DNA to bacterial DNA? - Who used bacteria to produce acetone? - Who used the first synthetic chemotherapeutic agent? - Who proposed a classification system for streptococci based on antigens in their cells walls?
- Jenner - Jacob and Monad - Fleming - Lederberg and Tatum - Pasteur - Stanley - Lister - Van Leeuwenhoek - Hooke - Iwanowski - Avery, MacLeod, and McCarty - Koch - Virchow - Beadle and Tatum - Berg - Weizmann - Elrlich -Lancefield
- _________ discovered a cholera outbreak at a water pump in London.
- John Snow
The Germ Theory of Disease: - 1860s: Applying Pasteur's work showing that microbes are in the air, can spoil food, and cause animal disease, _________ used a chemical antiseptic (_______) to prevent surgical wound infections. * ______ is a good primary germ barrier. - 1876: _________ discovered that a bacterium causes anthrax and provided the experimental steps, ____________, to demonstrate that a specific microbe causes a specific disease. * anthrax is caused from a _______ bacteria known as __________. * use this process to determine the _______ of a disease even to this day (where it comes from).
- Joseph Lister/ (phenol) * skin - Robert Koch/ Koch's postulates * soil/ Bacillus anthrasis * etiology
Which of the following conclusions can be drawn from Pasteur's experiment involving the flasks with S-shaped necks? Select all that apply! - Microbial life can arise from nonliving matter. - Microbial life can be destroyed by heat. - Pasteur's observations support the theory of spontaneous generation. - Microbes can be blocked from accessing favorable growth environments. - Microorganisms can be present in nonliving matter, such as air, liquids, and solids. - Beef broth is an unsuitable environment for growing microorganisms. - Pasteur's observations support the theory of biogenesis.
- Microbial life can be destroyed by heat. - Microbes can be blocked from accessing favorable growth environments. - Microorganisms can be present in nonliving matter, such as air, liquids, and solids. - Pasteur's observations support the theory of biogenesis.
Theory of Biogenesis: - What was the landmark for this theory? * provided paradime shift - Pasteur _______ flask keeps microbes out but allows air in. - Broth in the flask showed no __________. - Neck of the flask traps microbes. - Microorganisms originate in ______ or _______, not mystical forces.
- Pasteur and his S-shaped flask - swan neck - signs of life - air or fluids
The Golden Age of Microbiology: - 1857-1914 - Beginning with ________ work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs.
- Pasteur's
The First Observations: - 1665: ________ reported that living things are composed of little boxes, or cells (coined the term cells). * Observed a piece of cork. * Marked the beginning of the ________: all living things are composed of cells. - The first microbes were observed from 1623-1676 by __________. * He called them ________ when viewing them through the magnifying lenses (saw the first microorganisms). * Created what type of microscope and what were its magnification powers (human blood cells and sperm through original microscope.
- Robert Hooke * cell theory - Anton van Leeuwenhoek * Animalcules * simple microscope/ 70x - 250x
- _______ infects E coli. - Jim Humble: came up with a miracle mineral solution, which was basically ________.
- T4 virus - industrial bleach (ClO2-)
Select each statement that accurately describes what is happening to bacterial cultures during stationary phase. - The number of cells that are dying is balanced by the number of new cells that are being formed. - The cells are dead; therefore, the number is staying constant. - The cells are likely running out of nutrients. - Harmful waste products may be accumulating. - Cells are not increasing in number because they have not yet adjusted to the nutrient availability in the new media.
- The number of cells that are dying is balanced by the number of new cells that are being formed. - The cells are likely running out of nutrients. - Harmful waste products may be accumulating.
Bacterial Division: - Also known as ________ - Increase in _______ of cells, not cell ______. - Uses ________. - Budding (yeasts and molds) - Conidiospores (actinomycetes) - Fragmentation of filaments
- bacterial growth - number/ size - binary fission
Antibiotics: - ___________: proteins produced by one bacterium that inhibits another. - ______ and ________ prevent spoilage of cheese.
- bacteriocins - nisin and natamycin
- _________: is the study of bacteria. - ________: is the study of fungi. - _______: is the study of protozoa and parasitic worms.
- bacteriology - mycology - parasitology
Fluorescence Microscopy: - Uses ____ (_____ wavelength) light - Fluorescent substances absorb _______ and emit longer wavelength (visible) light. - Cells can be stained with fluorescent dyes (__________) if they do not naturally fluoresce. - Used a lot to identify _________ like _______.
- UV (short) - UV light - fluorochromes - microorganisms/ strep
Nomenclature: - After the first use, scientific names may be ________ with the first letter of the genus and the specific epithet: * Escherichia coli and Staphylococcus aureus are found in the human body. * E. coli is found in the ________, and S. aureus is on the ______.
- abbreviated * large intestine/ skin
Active Processes: - __________: requires a transporter protein and ATP; goes against gradient. - _________; requires a transporter protein and phosphoenolpyruvic acid (PEP); substance is altered as it crosses the membrane.
- active transport - group translocation
Culture Media: - Solid = ______. - Agar: * complex _________ * used as a ___________ for culture media in Petri plates, slants, and deeps. * generally not ______ by microbes. * liquifies at ______ * solidifies at ______
- agar * polysaccharide * solidifying agent * metabolized * 100 degrees C * about 40 degrees C
Chemical Sterilization: - Gaseous sterilants cause __________ - replacing hydrogen atoms of a chemical group with a _________. - Cross links ________ and _________. - Used for _________ material. * example?
- alkylation/ free radical - nucleic acid and proteins - heat-sensitive * ethylene oxide
Heavy Metals and their Compounds: - Heavy metals are ________ agents. - ____________: very small amounts exert antimicrobial activity. - _________ proteins. - Ag, Hg, Cu, and Zn * ________ is used to prevent ophthalmia neonatorum (newborn) * __________ prevents mildew in paint. * _________ is an algicide * ________ is found in mouthwash
- antimicrobial - oligodynamic action - denature * silver nitrate * mercuric chloride * copper sulfate * zinc chloride
- What are the steps of gram staining? - What does a mordant do?
- application of crystal violet (purple dye) - application of iodine (mordant) - alcohol wash (decolonization) - application of safranin (counterstain) - seals color of g+ to the surface of the cells.
- Which graph in Figure 7.2 best depicts the effect of placing the culture in an autoclave for 15 minutes at time x? a b c d e - Which graph in Figure 7.2 best depicts the effect of placing the culture at 7°C at time x? a b c d e
- b - d
Shapes of Bacteria: - Include? * rod-shaped = * spherical = * spiral = * what differentiates spirillum from spirochete? - Most bacteria are spherical because it requires the _________ to maintain the shape.
- bacillus, coccus, spiral, star-shaped, or rectangular * bacillus * coccus * vibrio, spirillum, and spirochete * spirochetes have an endoflagella - least amount of energy
What are the types of microorganisms (kingdoms)?
- bacteria, archaea, fungi, protozoa, algae, viruses, and multicellular animal parasites
Scanning Electron Microscopy: - An electron gun produces a _________ that scans the surface of an entire specimen. - Secondary electrons emitted from the specimen produce a ______ image. - Magnifies objects _____ to _______; resolution of ______. - Sweep across the entire specimen.
- beam of electrons - 3D - 1000 - 10000x/ 10 nm
- _________: is the use of microbes for practical applications, such as producing food and chemicals.
- biotechnology
- An adult human is composed of 10^13 __________. * harbors another 10^14 _________ (10x more) = these help provide _________ immunity. - The ________ is a community of microbes that live stably on/in the human body. * help to maintain ________. * can prevent growth of ________ microbes. * may help train the ________ to discriminate threats. - Microbes normally present in/on the human body are called _________.
- body cells * bacterial cells/ innate - microbiome * good health * pathogenic * immune system - normal microbiota
Special Culture Techniques: - Used with what type of organisms? - Capnophiles: * microbes that require high _______ conditions. * what type methods achieve these conditions?
- capnophiles * CO2 * CO2 packet or candle jar
Indicate the bacterial structures that are likely to be antigens, to which host antibodies bind, marking the invader for phagocytosis: nucleoid capsule flagella cell wall ribosomes plasmids fimbriae
- capsule/ flagella/ cell wall/ fimbriae
- What are the chemical requirements for microbial growth?
- carbon, nitrogen, sulfur, phosphorus, trace elements, oxygen, and organic growth factors.
Glycocalyx: - External to the ______. - ______ and gelatinous. - Made of _______ and/or ______. - Two types: * ______: neatly organized and firmly attached. * _____: unorganized and loose. - Contribute to __________: * capsules prevent _________. * extracellular polymeric substance helps form ______.
- cell wall (peptidoglycan) - viscous - polysaccharide/ polypeptide * capsule * slime layer - virulence * phagocytosis (hid from immune system) * biofilms
- What structures do all bacteria have? - What structures do only some bacteria have?
- cell wall, plasma membrane, cytoplasm, 70s ribosomes, nucleoid containing DNA - capsule, flagella, inclusions, plasmid, fimbriae
Culture Media: - ____________: exact chemical composition is known. * ________ organisms are those that require many growth factors provided in this type of media. * used in the growth of ________ and _______; microbiological assays. - __________: made from parts of yeasts, meat, or plants; chemical composition varies batch to batch (on the EXAM what should you look for to tell that it is this type of media?) * examples? * used in the growth of most __________ organisms.
- chemically defined media * fastidious * chemoautotrophs and photoautotrophs - complex media (extracts and digests) * nutrient broth and nutrient agar * chemoheterotrophic
The Birth of Modern Chemotherapy: Dreams of a Magic Bullet: - Treatment of disease with chemicals is called ________. - Hurdle: scientists can develop a drug that kills a bacteria but also the host = _________; looking for the magic bullet! - Chemotherapeutic agents used to treat infectious disease can be __________ or _________. - _______ are chemicals produced by bacteria and fungi that inhibit or kill other microbes (do not work against _________). * Why would doctors give penicillin (for bacteria) if you have a virus (viral infections do not react to penicillin)?
- chemotherapy - cross reactivity - synthetic drugs or antibiotics - antibiotics (viruses) - to prevent a second infection (bacterial) because the immune system is already weak from the viral infection.
The Nucleoid: - Bacterial _________ (nucleoid): _____ thread of DNA that contains the cell's genetic information. - ________: extrachromosomal genetic elements; carry non-crucial genes that help with ________ and ________.
- chromosome/ circular, singular - plasmids/ antibiotic resistance and production of toxins
- What are the three major morphologies? - What does red around the type of microscope mean? - What is the reproductive part of fungi? - Amoeba use ______ for movement and engulfing food particles .... macrophages use these too.
- coccus (round)/ bacillus (rod)/ and spiral (corkscrew) - the specimen has been artificially colored - sporangia - pseudopods
Biofilms: - Microbial ____________. - Form ______ or ________ that adhere to surfaces. * bacteria communicate cell-to-cell via __________. - Share ________. - Shelter bacteria from _______ environmental factors. - Found in ________ and sewage treatment systems; can clog pipes. - _______ resistant to microbicides. - Involved in _____% of infections * Examples of places that can get infections?
- communties - slime or hydrogels * quorum sensing - nutrients - harmful - digestive system - 1000x - 70 * catheters, heart valves, contact lenses, and dental caries
Aldehydes: - Inactivate proteins by __________ with functional groups (NH2, OH, COOH, SH) = prevents 3D structure = can't function. - Used for preserving specimens and in ___________. - Formaldehyde and ortho-phthalaldehyde - _________ is one of the few liquid chemical sterilizing agents. - LOOK AT PICTURE OF BASIC ALDEHYDE STRUCTURE.
- cross-linking - medical equipment - glutaraldehyde
Cell Walls and the Gram Stain Mechanism: - ________ crystals form inside cell. - Gram-positive: * _______ dehydrates peptidoglycan * CV-I crystals ________. - Gram-negative: * alcohol dissolves _______ and leaves holes in ________. * CV-I _______; cells are colorless. * ______ added to stain cells. - What are the four steps of the staining process?
- crystal violet-iodine * alcohol * do not leave * outer membrane/ peptidoglycan * washes out * safranin - 1. crystal violet (basic purple dye) for 1 minute/ 2. mordant (iodine) = sticks dye to bacteria = 1 minute/ 3. decolorizer (alcohol) = seconds/ 4. counterstain (red safranin) = 1 minute.
Culture Media: - _________: nutrients prepared for microbial growth. - ________: no living microbes - ________: introduction of microbes into a medium (mixing). - _______: microbes growing in or on a culture medium.
- culture medium - sterile - inoculum or inoculation - culture
- _________ substance inside the plasma membrane and outside the nucleus. - ________: fluid portion of cytoplasm - ________: made of microfilaments and intermediate filaments; give _______ and _______. - ________: movement of the cytoplasm throughout a cell.
- cytoplasm - cytosol - cytoskeleton/ shape and support - cytoplasmic streaming
Preserving Bacterial Cultures: - What are two methods for preserving bacteria? * How do these methods preserve the bacteria? * Deep-freezing: ______ to _____ degrees C. * Lyophilization (freeze-drying): frozen (_______ to _______ degrees C) and _______ in a vacuum.
- deep-freezing or lyophilization (freeze-drying) * the lower temperatures cause metabolism and molecular vibrations to slow down. * -50 - -95 * (-54 - -72)/ dehydrated(desiccate)
Surface Active Agents: - Soap = ________; emulsification - Acid-anionic sanitizers = anions react with __________. - Quaternary ammonium compounds (quats) = cations are _________, _______ proteins, and disrupt ___________.
- degerming - plasma membrane - bactericidal, denature, plasma membranes
Why 70% ethanol instead of 95%: - Protein _________ is the mode of action in alcohol sterilization. Since pure ethyl alcohol is a dehydrating agent and water supports the denaturing of proteins, the proteins are denatured more readily by ethanol in the presence of _______. * if the percent is too high, the bacteria still grow because all of the proteins just _________ on the cells = cannot penetrate the plasma membrane to kill it.
- denaturation/ water * clump
Heat: - Heat ________ enzymes. - ______________: lowest TEMPERATURE at which all cells in a liquid culture are killed in 10 minutes (specific). - _____________: minimal TIME for all bacteria in a liquid culture to be killed at a particular temperature. - ______________ minutes to KILL 90% of a population at a given temperature (like in the microbial death curve).
- denatures - thermal death point (TDP) - thermal death time (TDT) - decimal reduction time (DRT)
Moist Heat Sterilization: - Moist heat ________ proteins (allows heat to penetrate the _________). *boiling * free-flowing steam - __________: steam under pressure. * specifications? (most vegetatively growing organisms will be killed at this) * kills all organisms and _________. * ______ must contact the item's surface/ the _________ allows for boiling without overflowing of liquid.
- denatures/ (plasma membrane) - autoclave * 121 C/ 15 psi/ 15 minutes * steam/ pressure
Arrangement of Coccus Bacterial Cells: - Pairs: - Clusters: - Chains: - Groups of four: - Cube-like groups of eight:
- diplo- - staphylo- - strepto- - tetrads - sarcinae
- ___________ for microbial growth: count microbial cells. * what are the four ways that can achieve this? - What are the three indirect methods for estimating bacterial numbers?
- direct measurements * plate count, filtration, most probable number (MPN) method, and direct microscopic count - turbidity, metabolic activity, and dry weight
- Differential Stains: used to _______ between bacteria. * what are the two types?
- distinguish * gram stain and acid-fast stain
Generation Time: - Time required for a cell to _________: _____ minutes to 24 hours. - Binary fission _______ the number of cells each generation. - Total number of cells = _________ - ________ are represented logarithmically or exponentially.
- divide/ 20 - doubles - 2^ number of generations - growth curves
Mitochondria: - ______ membrane. - Contain inner folds (________) and fluid (_______) - Involved in __________ (ATP production).
- double - (cristae)/ (matrix) - cellular respiration
The Disk Diffusion Method: - Evaluates _______ of chemical agents. - Filter paper disks are soaked in a chemical and placed on a culture. - Look for the _________ around the disk, this indicates how well the chemical works against the microbe. * ie the ____________ = the better the chemical substance is. - cannot differentiate between bactericidal or bacteriostatic.
- efficacy - zone of inhibition * bigger halos
What microscope allows for the highest resolution and magnification?
- electron microscope
Electron Microscopy: - Uses _______ instead of light. - The shorter wavelength of electrons gives _________. - Used for images too small to be seen with light microscopes, such as _________.
- electrons - higher resolution - viruses
Axial Filaments: - Also called _________. - Found in _________. - Anchored at one end of a cell. - Rotation causes cell to move like a _________ because it is wrapped around the actual bacteria.
- endoflagella - spirochetes - corkscrew
- _________: encourages the growth of a desired microbe by increasing very small numbers of a desired organism to detectable levels. * usually a _______.
- enrichment culture * liquid
Algae Characteristics: - __________ - _________ cell walls - Found in freshwater, saltwater, and soil - Use _________ for energy - Produce ________ and __________. - ALL LIFE RESULTS FROM THESE GUYS! - __________; are the ancestral precursors for land plants. - A lot of algae are communal, meaning ________. - 6 CO2 + 6 H20 -> (sun) O2 + sugar! - Are green because chlorophyll A and B ______ all colors except green and _______ it.
- eukaryotes - cellulose - photosynthesis - oxygen and carbohydrates - spirogyra - numerous single cells working together in a colony. - absorb/ reflect
Fungi Characteristics: - _________ (distinct nucleus) - ______ cell walls - Absorb ______ chemicals for energy - _______ are unicellular examples - _______ and ________ are multicellular examples * Molds consist of masses of ________, which are composed of filaments called _______. - ________: mold that grows on wheat and bread (green color).
- eukaryotes - chitin - organic - yeasts - molds and mushrooms * mycelia/ hyphae - mucor
Multicellular Animal Parasites Characteristics: - __________ - Multicellular animals - Not strictly _________. - Parasitic flatworms and roundworms are called _________. - Have some microscopic stages in their _________.
- eukaryotes - microorganisms - helminths - life cycles
Protozoa (protists) Characteristics: - ___________ - Absorb or ingest _______ chemicals - May be motile via _________. - _________ or ________(derive nutrients from a living host) - Use _________ to digest food, and use amoeboid action = extensions known as _________. - ________ are major examples.
- eukaryotes - organic - pseudopods, cilia, or flagella - free-living or parasitic - phagocytosis/ pseudopods - amoeba
Passive Processes: - __________: solute combines with a transporter protein in the membrane. * transports _____ and _______ across a membrane with the concentration gradient. - _________; the movement of water across a selectively permeable membrane from an area of high water to an area of low water concentration. * through ______ layer/ ______ (water channels)
- facilitated diffusion * ions and larger molecules - osmosis * lipid/ aquaporins
Cilia are appendages that allow locomotion in bacteria: - true or false
- false
The avian influenza A virus is transmitted only between birds: - true or false
- false
- Pasteur showed that microbes are responsible for __________. - Fermentation is the microbial conversion of ______ to ________ in the absence of air. - Microbial growth is also responsible for _______ of food and beverages. - Bacteria that use air spoil wine by turning it to _______ (_________) - Fermentation for animals creates ________. - Lower temperatures in fridge slows down metabolism of bacteria = extends lifetime of food.
- fermentation - sugar/ alcohol - spoilage - vinegar (acetic acid) - lactic acid
Flagella: - _______ appendages external of the cell. - _______ bacteria. - Made of protein _______. - Movement is _______ driven. - Three parts: * ________: outermost region. * ________: attaches to the filament. * _______: consists of rod an pairs of rings; anchors flagellum to the cell wall and membrane. - Flagella allow bacteria to move toward or away from stimuli (________) - Flagella rotate to _____ or ______. - Flagella proteins are ________ and distinguish among _______ (e.g. Escherichia coli O157:H7) = (ie this is an ___________). - ________: foreign substances that cause the immune system to make antibodies.
- filamentous - propel - flagellin - ATP * filament * hook * basal body - (taxis) - run or tumble - H antigens/ serovars/ (antigenic flagella) - antigens
Filtration: - Solution passed through a ______ that collects bacteria. - Filter is transferred to a _______ and grows as colonies on the surface. - Used for bacteria that are in ________ samples (like E. coli in sewage). - Pore size is 2 micrometers, capturing most bacteria, but what won't be captured in this method?
- filter - Petri dish - water - viruses
1. ____________:used after initial focusing to sharpen the image 2. ____________:controls how much light from the illuminator reaches the specimen 3. _____________:used for initial focusing; should never be used when the high-power objective lens or oil immersion objective lens is in place 4. _____________:used to focus the light from the illuminator onto the slide 5. ____________:lens that is closest to the slide and provides initial magnification of a specimen 6. _____________:lens that you look through 7. ___________:platform on which the slide is placed for viewing
- fine focus knob - diaphragm - coarse focus knob - condenser lens - objective lens - ocular lens - stage
Two-Photon Microscopy: - Cells are stained with __________. - Two photons of __________ light are used to excite the dyes. - Can study living cells up to _____ deep.
- fluorochrome dyes - long-wavelength (red) - 1mm
Confocal Microscopy: - Cells are stained with __________. - ___________ light is used to excite a single plane of a specimen. - Each plane in a specimen is illuminated and a 3D image is constructed with a _________.
- fluorochrome dyes - short-wavelength (blue) - computer
- Psychrotrophs cause __________. - Thermophiles are found in ________ and _______.
- food spoilage - hot springs and organic compost
Gram Stains: - Classifies bacteria into _______ or _______. - Gram positive bacteria have thick ___________ - Gram negative bacteria have thin _________ and a layer of __________. - This staining method allows us to determine and differentiate = put in a category.
- gram-negative or gram-positive - peptidoglycan cell walls - peptidoglycan cell walls/ lipopolysaccharides
- coccus are usually _______. - rods are usually _______. * if flipped then they are pathogenic.
- gram-positive (purple) - gram-negative (red)
- Pasteur demonstrated that spoilage bacteria could be killed by _______ that was not hot enough to evaporate the alcohol in wine. - __________ is the application of a high heat for a short time to kill harmful bacteria in beverages = reduce the number of bacteria and extend the lifetime of the product (these bacteria were ________). **** Pasteurization is not _________ *****
- heat - pasteurization/ (heat labile) - sterilization
Physical Requirement: Osmotic Pressure: - __________ environments (higher in solutes than inside the cell) cause ________ due to high osmotic pressure. - _________ or _________ require high osmotic pressure (high salt). - _________ tolerate high osmotic pressure. - _________: restricted to a particular function or mode of life. - _________: capable of but not restricted to a particular function or mode of life.
- hypertonic/ plasmolysis (imploding) - extreme and obligate halophiles - facultative halophiles - obligate - facultative
- _______: is the study of immunity. * _______ and _______ are used to prevent and cure viral diseases. - A major advance in immunology occurred in 1933 when ________ classified streptococci based on their cell wall components. * The grouping of streptococci into distinct groups is based on its _________ and macrophages identify these for destruction.
- immunology * vaccines and interferons - Rebecca Lancefield * cell wall
Identify antibacterial strategies that would likely be selectively toxic for bacteria: inhibition of peptidoglycan synthesis interfering with translation at 70s ribosomes interfering with lysosomal function inhibition of fimbriae synthesis inhibition of microtubule function
- inhibition of peptidoglycan synthesis/ interfering with translation at 70s ribosomes/ inhibition of fimbriae synthesis
Radiation (kills cells): - ___________: X-rays, gamma rays, and electron beams. * ionizes water to create reactive ____________. * damages ______ by causing lethal mutations. * strips off _______ from the atoms, causing free radical to form. * used to sterilize _______. - __________: UV, 260 nm * damages DNA by creating ___________ = results in damaged transcription and translation. - ___________; kill by heat; not especially ___________ (some microorganisms can survive). * impact covalent bonds in _______ = causes vibrations. - __________ wavelengths = higher energy (explain).
- ionizing radiation * hydroxyl radicals * DNA * charges/electrons * Petri dishes - non ionizing radiation * thymine dimers - microwaves/ antimicrobial * water - shorter/ (gamma rays have shorter wavelength than microwaves = just look at how much more DAMAGE gamma rays cause)
- __________: solute concentrations equal inside and outside of cell; water is at equilibrium. - _________: solute concentration is lower outside than inside the cell; water moves into cell, causing ___________. - _________: solute concentration is higher outside of cell than inside; water moves out of cell, causing _________. - ________: the pressure needed to stop the movement of water across the membrane. * what environment were meats placed in for preservation before refrigerators?
- isotonic solution - hypotonic solution/ osmotic lysis (cell bursts) - hypertonic solution/ plasmolysis (imploding/ cell wall stay intact) - osmotic pressure * hypertonic
Recycling Vital Elements: - _________: is the study of the relationship between microorganisms and their environment. - Bacteria convert ______, _____, ______, ______, and ______ into forms used by plants and animals (are crucial to recycle the energy from producers and consumers = _________)
- microbial ecology - carbon, oxygen, nitrogen, sulfur, and phosphorus/ (decomposers)
Phase of Growth: - What are the phases of bacterial growth? - _______: intense activity preparing for population growth, but no increase in population. - _______: exponential increases in population. - ______: period of equilibrium; microbial deaths balance production of new cells (why does this occur?). - _______: population is decreasing at a logarithmic rate. - What are the two phases that use logs?
- lag phase, log phase, stationary phase, and death phase - lag phase - log phase - stationary phase/ (nutrients are used up/ no space/ and wastes toxify the environment) - death phase - log growth and log death
- __________: any kind of microscope that uses visible light to observe specimens. - Types include?
- light microscope - compound light microscope/ dark field microscopy/ phase-contrast microscope/ differential interference contrast (DIC) microscopy/ fluorescence microscopy/ and confocal microscopy
Darkfield Microscopy: - ______ objects are visible against a _______ background. - ________ placed in condenser. - Only light is reflected off the ________ and enters the objective lens.
- light/ dark - opaque disk - specimen
- Which of the lines best depicts the log phase of a thermophile incubated at room temperature? - Which of the lines best depicts the log phase of Listeria monocytogenes growing in a human
- line C - line A
Phenol and Phenolics: - Injure or target the _______ of ____________, causing leakage. - ________: contain two phenol groups connected by a bridge (hexachlorophene and triclosan) * disrupts the ___________.
- lipids of plasma membranes - bisphenol * plasma membranes
Phase-Contrast Microscopy: - Allows examination of ________ and ________. - Brings together two sets of light rays; ______ and ______; to form an image. - ________ = microorganism can move around.
- living organisms and internal cell structures - direct rays and diffracted rays - hanging drop sample
Flagella and Cilia: - Projections used for _______ or moving substances along the cell surface. - ________: long projections; few in number - ________: short projections; numerous. - Both consist of _______ made of the protein _______. * microtubules are organized as _____ pairs in a ring, plus ______ microtubules in the center (______ array). - Allow flagella to move in a _______ manner.
- locomotion - flagella - cilia - microtubules/ tubulin * nine/ two/ (9+2) - wavelike
Flagella Staining: - Flagella are structures of _________. - Uses a _______ and ________.
- locomotion - mordant and carbolfuchsin
Physical Methods for Microbial Control: - _________ has a bacteriostatic effects. * examples: refrigerator, deep-freezing, and _________ (freeze drying). - _________ denatures proteins. - _________: absence of water prevents metabolism. - __________: uses salts and sugars to create hypertonic environment; causes ________ of the cell.
- low temperatures * lyophilization - high pressure - desiccation - osmotic pressure/ plasmolysis
Terms: - _________: breaking down of the membrane of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity (mechanical). - ________: occurs when a cell bursts due to an osmotic imbalance that has caused excess water to move into the cell. - ________: process in which cells lose water in a hypertonic solution, plasma membrane pulls away from cell wall (plants and bacteria).
- lysis - cytolysis - plasmolysis
Organelles: - __________: vesicles formed in the Golgi complex/ contain digestive enzymes. - __________: cavities in the cell formed from the Golgi complex/ bring food into cells; provide shape and storage. - _________: oxidize fatty acids; destroy H2O2. - _________: networks of protein fibers and centrioles/ form the mitotic spindle; crucial role in cell division.
- lysosomes - vacuoles - peroxisomes - centrosomes
Damage to Cell Wall: - _______ hydrolyzes bonds in peptidoglycan (in tears, sweat, and saliva). - ______ inhibits peptide bridges in peptidoglycan - ________ is a wall-less gram-positive cell. - ________ is a wall-less gram-negative cell. * both other the previous ones are susceptible to ________. - ______ are wall-less cells that swell into irregular shapes.
- lysozyme - penicillin - protoplast - spheroplast * osmotic lysis - L forms
Actions (Effects) of Microbial Control Agents on Cellular Structures: - Alteration of ___________. - Damage to ______ (enzymes). - Damage to _________.
- membrane permeability - proteins - nucleic acids
Inclusions: - ___________: phosphate reserves. - ___________ (3): energy reserves - ___________: RuBisCO enzyme for CO2 fixation during photosynthesis. - __________: protein-covered cylinders that maintain buoyancy. - __________: iron oxide inclusions; destroy H2O2 * doesn't constitute as a ________.
- metachromatic granules (volutin) - polysaccharide granules, lipid inclusions, and sulfur granules - carboxysomes - gas vacuoles - magnetosomes * organelle
Atomic Force Microscopy: - Uses a _______ placed onto a specimen. - Produces ______ images
- metal-and-diamond probe - 3D
Bioremediation: - Using microbes to clean up ________. - Ex. Bacteria degrade organic matter in _______. - Ex. Bacteria degrade or detoxify pollutants such as _____ and ______. - Ex. landfill = bacteria convert waste into ___________ - Ex. bacteria who help in oil spills and in wells.
- pollutants - sewage - oil and mercury - methane
Recombinant DNA Technology: - __________: the study of how microbes inherit traits. - _________: the study of how DNA directs protein synthesis. - _________: the study of an organism's genes; has provided new tools for classifying microorganisms. - _________: DNA made from two different sources. * In the 1960s, __________ inserted animal DNA into bacterial DNA, and the bacteria produced an animal protein.
- microbial genetics - molecular biology - genomics - recombinant DNA * Paul Berg
- Microorganisms are measured in ___________ and _________. - List the metric system units!
- micrometers (um) and nanometers (nm) - Exa: E: 10^18/ Peta: P: 10^15/ Tera: T: 10^12/ Giga: G: 10^9/ Mega: M: 10^6/ Kilo: k: 10^3/ Hecto: h: 10^2/ Deka: da: 10^1/ deci: d: 10^-1/ centi: c: 10^-2/ milli: m: 10^-3/ micro: u: 10^-6/ nano: n: 10^-9/ pico: p: 10^-12/ femto: f: 10^-15/ atto: A: 10^-18
- __________: are organisms that are too small to be seen with the unaided eye. - __________: include bacteria, fungi, protozoa, microscopic algae, and viruses.
- microorganisms - microbes
Physical Requirements Temperature: - What are the 3 cardinal temperatures to consider for each bacteria? - ___________: cold-loving bacteria. - __________: grow between 0 and 20-30 degrees C. Cause food spoilage. - _________: moderate-temperature-loving bacteria (what is special about these?) * How does the innate immune system help kill bacteria? - _________: heat-loving/ optimum growth temperature of 50-60 degrees C/ found in hot springs and organic compost. - ________: optimum growth temperature above 80 degrees C.
- minimum growth temperature, optimum growth temperature, and maximum growth temperature - psychrophiles - psychrotrophs - mesophiles (this is around body temperature = bacteria of the body fall in this category = physicians are most concerned with these) * fever = slow down metabolism of bacteria = fight it! - thermophiles - hyperthermophiles
3 Cardinal Temperatures: - First, what are the 3 cardinal temperatures? - Psychophiles = ? - Psychotrophs = ? - Mesophiles = ? - Thermophiles = ? - Hyperthermophiles = ?
- minimum growth temperature, optimum growth temperature, and maximum growth temperature ALL OF THE ANSWERS ARE IN CELSIUS - -7/ 12/ 18 (can survive in when water freezes and in refrigerator) - 0/ 22/ 31 (can survive in refrigerator and at room temperature) - 10/37/ 48 (can survive at room temperature and body temperature) - 40/61/ 72 - 66/ 92/ 110
- ________ staining is used for capsules. - Capsules are important for bacteria because they? - Suspension of _______ or ________ contrasts the background within the capsule, which appears as a _____ around the cell.
- negative - camouflage the bacteria = eludes the immune system (covers proteins) = increases valiance (ability to cause disease) - India ink or nigrosin/ halo
Virus Characteristics: - _________ chemicals - ________ (not made of cells) = STRIKE - Consist of _____ or ______ core. - Core is surrounded by a ________ coat. - Coat may be enclosed in a __________. * those without = _______ * those with this, get it from the host cell they infect (take some of its ___________). - Are replicated only when they are in a living host cell (________________) * Some bacteria also have to do this (must reproduce inside the cell) = not differentiating between viruses and bacteria. EX. _______ or ______. - Insert outside living hosts (cannot _________ on their own) = STRIKE
- nonliving - acellular - DNA or RNA - protein - lipid envelope * naked * cell membrane - (obligate intracellular parasite)/ chlamydia or rickettsia - reproduce
- _________: is the collection of acquired microorganisms on/in a healthy human being. * being to be acquired as newborns (explain exposure of bacteria at birth!) * may colonize the body indefinitely (_________) * may colonize the body fleetingly (making them _________ microbiota) = most pathogens are this type. - __________ can only occur at body sites that provide nutrients and the right environment for the microbes to flourish.
- normal microbiota * amnionic sac is sterile, and at birth they are exposed to numerous amounts of bacteria * resident * transient - colonization
The Rate of Microbial Death: - Effectiveness of treatments depends on what 4 things? - Bacteria die in an ___________ way (what percent dies with one log decrease?)
- number of microbes, environment (organic matter, temperature, biofilms), time of exposure, and microbial characteristics - exponential (90%)
Chemical Requirement: Oxygen: - ___________; require oxygen (what is the reason why humans need oxygen?) - ___________; grow via fermentation or anaerobic respiration when oxygen is not available. - ___________; unable to use oxygen and are harmed by it. - ___________; tolerate but cannot use oxygen. - ___________; require oxygen concentration lower than air. - GO OVER PRINTED PICTURE!!!!!!!
- obligate aerobes (ETC: oxygen takes up the extra electrons (free radicals) and makes water) - facultative anaerobes - obligate anaerobes - aerotolerant anaerobes - microaerophiles
- __________: remagnifies the image formed by the objective lens. - _________: transmits the image from the objective lens to the ocular lens. - _________: primary lenses that magnify the specimen. - ________: holds the microscope slides in position. - ________: focuses light through the specimen. - _________: controls the amount of light entering the condenser. - ________: light source.
- ocular lens - body tube - objective lenses - stage - condenser - diaphragm - illuminator
Most Probable Number (MPN) Method: - Multiple tube test - Count _______ tubes - Compare with a ________.
- positive - statistical table
Compound Light Microscopy: - In a compound microscope, the image from the objective lens is magnified again by the ____________. - _________ is the process of enlarging the appearance, not physical size, of something. - ___________ = objective lens x ocular lens - _________: area seen in the microscope. - _________: is the ability of the lenses to distinguish two points. * A microscope with a resolving power of 0.4 nm can distinguish between two points at least 0.4 nm apart. * __________ of light provide greater resolution (what colors have the greats resolution based on the color spectrum). - The __________ is a measure of the light-bending ability of a medium. * light may refract after passing through a specimen to an extent that it does not pass through the _____________ (effects __________). * _________ is used to keep light from refracting (used at high magnifications). This substance _______ light towards the objective lens.
- ocular lens - magnification - total magnification - field of view - resolution * shorter wavelengths (Y, I, G) - refractive index * objective lens/ (resolution) * immersion oil/ compresses
- A simple microscope has _____ lens and was invented by ________.
- one/ Anton van Leeuwenhoek
Golgi Complex: - Transport ________. - Modifies _______ from the ER. - Transports modified proteins via _________ to the plasma membrane.
- organelle - proteins - secretory vesicles
The Cell Wall: - Prevents _______ and protects the cell membrane. - Made of ______ (in bacteria) - Contributes to ________.
- osmotic lysis - peptidoglycan - pathogenicity
Dry Heat Sterilization: - Kills by direct application of heat. - Kills with _________. - Example?
- oxidation - flaming, incineration, and hot-air sterilization (oven)
Special Stains: - Used to distinguish ______ of microorganisms. - What are the three types of special stains?
- parts - capsule stain, endospore stain, and flagella stain
The Movement of Materials Across Membranes: - __________: substances move from high concentration to low concentration; _______ expended (DIFFUSION). - _________: substances move from low concentration to high concentration; ______ expended.
- passive processes/ no energy - active processes/ energy
Heat: - __________: reduces spoilage organisms and pathogens, but is NOT a form of _____________. - Equivalent treatments: * ______ degrees C for 30 minutes. * _________________: ______ degrees C for 15 seconds (USA and Canada = 7-10 days). * _______________: ______ degrees C for 4 seconds (Europe = 3 months) - __________ organisms will survive pasteurization. - duric = _______.
- pasteurization/ sterilization * 63 * high-temperature short time (HTST): 72 * ultra-high temperature (UHT): 140 - thermoduric - durable
Microbes in Our Lives: - A few are _________ (disease-producing), while most are beneficial (have a ________ relationship). - Some ________ organic waste. - Some generate oxygen by _____________ (ex. __________). - Some produce ____________ such as ethanol, acetone, and vitamins. - Some produce _________ such as vinegar, cheese, and bread. - Some produce products used in _____________ (cellulase) and ______________ (insulin).
- pathogenic/ (synergist) - decompose - photosynthesis (cyanobacteria) - chemical products - fermented foods - manufacturing/ disease treatment
Normal Microbiota: - Normal microbiota prevent growth of _________. - Normal microbiota produce growth factors such as ______ and ______. - _________ is the ability of the body to ward off disease. * resistance factors include ______, ________, and _________. * provide an immunological benefit called __________. ***** First thing pathogens have to do for infection to occur is to _________ ******
- pathogens - vitamin B and K - resistance * skin, stomach acid (helicobacter neutralize stomach acid) , and antimicrobial chemicals * bacterial antagonism ***** attach *****
Gram-Negative Cell Walls: - _______ between the outer membrane and the plasma membrane contains peptidoglycan (______ layer). - Outer membrane made of _______, ________, and ________. - Protect from ______, ______, and _______. - Made of ____________ (is a strong antigen that causes ________). * _________ functions as antigens (antigenic LPS). * _______ is an endotoxin embedded in the top layer. - ________(proteins) form channels through membrane. - What happens if you destroy a single gram-negative bacteria into lots of pieces?
- periplasm/ (thin) - polysaccharides, lipoproteins, and phospholipids - phagocytes, complement, and antibiotics - lipopolysaccharide (LPS)/ (fever) * O polysaccharide * Lipid A - porins - antigenic storm = amplify immune response = shock (sepsis)
Flagella Types: - ___________; multiple flagella everywhere. - ___________; one flagella. - ___________; multiple flagella on polar end. - ___________; multiple flagella on both ends.
- peritrichous - monotrichous - lophotrichous - amphitrichous
The Plasma (cytoplasmic) Membrane: - __________ that encloses the cytoplasm. - ________ on the membrane surfaces. - ______ and ______ proteins penetrate the membrane. - These proteins are what the _________ looks for in order to identify the cells.
- phospholipid bilayer - peripheral proteins - integral and transmembrane - immune system
Chloroplasts: - Locations of __________. - Contain flattened membranes (________) that contain chlorophyll.
- photosynthesis - (thylakoids)
Cytoplasm: - The substance inside the _______. - Eighty percent ______ plus proteins, carbohydrates, lipids, and ions. - Rigidity: _________ for eukaryotes and _________ for prokaryotes.
- plasma membrane - water - cytoskeleton/ cell wall
Preparing Smears for Staining: - Stains consist of a _______ and _____ ion, one of which is colored (______). - In a ______, the chromophore is a cation (+). * note: the polar head of phospholipids has an intrinsic ________. - In an _______, the chromophore is an anion (-) - Staining the background instead of the cell is called ________. - Using an _____ dye with stain everything but the cell and using a ____ dye with usually stain the cells (like bacteria).
- positive and negative/ (chromophore) - basic dye * negative charge - acidic dye - negative staining - acidic/ basic
- Prokaryote comes from the Greek words for ________. - Eukaryote comes from the Greek words for ________.
- prenucleus - true nucleus
Differential Interference Contrast (DIC) Microscopy: - Similar to phase-contrast - Uses two light beams and ________ to split light beams, giving more _____ and _____ to the specimen.
- prisms/ contrast and color
Archaea Characteristics: - ____________ - Lack _________ cell walls * May have ___________ (unusual for single celled organisms) - Often live in _________ environments = called __________. - Include: * _________ (CO2 -> CH4) * ___________ (salt) * ___________ (temperature) - Generally not known to cause ________ in humans. - What is the normal salt content for humans? * most pathogens have coevolved with us = why we get sick.
- prokaryotes - peptidoglycan * no cell wall - extreme/ extremophiles * methanogens * extreme halophiles * extreme thermophiles - disease - .85%
Bacteria Characteristics: - ____________ (pre-nucleus) = no ________. The DNA is ________. - ________ celled - ________ cell walls (carbohydrate polymer matrix = protects the bacteria against ____________) - Divide via ________ (genetically identical offspring) - Derive nutrition from ______ or _______ chemicals or __________. - May swim by using moving appendages called ________. - E. coli divide every _____ minutes, meaning they have __________ rates.
- prokaryotes/ no membrane bound organelles or nucleus/ floating around freely - single - peptidoglycan/ (osmotic pressure changes) - binary fission - organic or inorganic/ photosynthesis - flagella - 20/ exponential growth
Ribosomes: - Sites of ________. - Made of _____ and ribosomal ______. - Prokaryotes = _______ (____S + _____S) - Eukaryotes = _______ (____S + ______S) * sedimentation coefficients in ________ units. * why are the S units important?
- protein synthesis - protein/ RNA - 70S (50/ 30) - 80S (60/ 40) * Svedberg * doctors exploit the difference in S units in order to target cells with protein synthesis inhibitors.
Alcohol: - Denature ________ and dissolve _______. - No effect on ________ and _________. - Ethanol and isopropanol: require ________.
- proteins/ lipids - endospores and non enveloped viruses - water
Obtaining Pure Cultures: - A _________ contains only one species or strain. - A _______ is a population of cells arising from a single cell or spore or from a group of attached cells. - A colony is often called a ___________. - The _________ is used to isolate pure cultures.
- pure culture - colony - colony-forming units (CFU) - streak plate method
The First Synthetic Drugs: - ________ from tree bark was long used to treat malaria (is a ________ that lives in salivary mucosa). - _________ speculated about a magic bullet that could destroy a pathogen without harming the host. * 1910: He developed a synthetic ______ drug, ________, to treat syphilis. - 1930s: _________ were synthesized.
- quinine (plasmodium) - Paul Ehrlich * arsenic/ salvarsan - sulfonamides
- ____________: enables bacteria and fungi to produce a variety of proteins, vaccines, and enzymes. * Missing or defective genes in human cells can be replaced in __________. * Genetically modified bacteria are used to protect crops from _______ and from ________. * Is an example of _________. * Two examples of this type of DNA are _______ and _______, which allow us to purify and produce large amounts.
- recombinant DNA technology * gene therapy * insects/ freezing * biotechnology * insulin and Bt endotoxin gene (plants)
Anaerobic Growth Media and Methods: - Uses what? - Reducing media: * used for the cultivation of __________. * contains chemicals (_____________) that combine O2 to deplete it. * _______ to drive off O2.
- reducing media * anaerobic bacteria (obligate) * (sodium thioglycolate) * heated
- When a pathogen invades a host and overcomes the host's _________, disease results. - ____________: new diseases and diseases increasing in incidence. - What are the main EIDs we need to know?
- resistance - emerging infectious diseases (EIDs) - E coli. O157:H7, Middle East respiratory syndrome (MERS), avian influenza A (H5N1), methicillin-resistant Staphylococcus aureus (MRSA), west nile encephalitis (WNE), bovine spongiform encephalopathy (mad cow), ebola hemorrhagic fever (EHF), crytosporidiosis, acquired immunodeficiency syndrome (AIDS)
Endospore Staining: - Endospores are _________, _______ structures inside some cells that cannot be stained by ordinary methods. - Endospores are NOT a _________, they are a ___________ = survival mechanism. - Primary stain: ________, usually with heat (forces color into spores) - Counterstain: ________ - Spores appear ______ within _____ or ______ cells. - What are two examples of endospores? - Endospores can be inside canned food -> bulging from gases trapped -> _______ interferes with germination of endospores.
- resistant, dormant (highly resistant to heat and antibiotics) - reproductive organs, time capsule - malachite green - safranin - green/ red or pink - clostridium and bacillus (anthrax) - nitrates
Endospores: - _____ cells; produced when ________ are depleted. - Very _______ to desiccation (_________), heat, chemicals, and radiation and antibiotics. - Produced by _______ and _______ (both soil bacteria). - __________; endospore formation. - _________; endospore returns to vegetative state (growing and dividing = make new bacteria) - NOT a _____________; rather a tie capsule. - Can all bacteria make these? - Important in food production because ________ interfere with germination processes.
- resting/ nutrients - resistant/ (removal of water) - Bacillus and Clostridium - sporulation - germination - reproductive organ - no - nitrates
- __________: are the sites of protein synthesis. - 80S: * consists of the large ______ subunit and the small _______ subunit. * membrane bound: attached to _______. * free: in ________. - 70S; * in _______ and ________.
- ribosomes * 60S/ 40S * ER * cytoplasm * chloroplasts and mitochondria
Select the structures below that are found in all bacterial cells. flagella ribosomes capsule cell wall plasma membrane nucleoid cytoplasm fimbriae pilus (pili)
- ribosomes/ plasma membrane/ nucleoid/ and cytoplasm
Identify the picture and determine the scenario(s) in which airborne microbial contamination of the sterile broth is most likely to occur: - scenario a: break near the mouth of the flask - scenario b: break before the first curve in the S-shaped neck - scenario c: break between the first and second curve in the S-shaped neck - scenario d: break after the second curve in the S-shaped neck
- scenario a: break near the mouth of the flask - scenario b: break before the first curve in the S-shaped neck
Filtration: - Passage of substances through a _________ material. - Used for ________ materials. - ___________: remove microbes > 0.3 micrometers. - _________: remove microbes > 0.22 micrometers/ these will not trap _______.
- screenlike - heat-sensitive - high-efficiency particulate air (HEPA) filters - membrane filters/ viruses
Plasma Membrane Functions: - The plasma membrane's _________ allows the passage of some molecules, but not others. - Contains enzymes for _____ production. - Some membranes have photosynthetic pigments on foldings called __________. - Damage to the membrane by ______, _________, and _______ causes leakage of cell contents (disrupts its integrity). - The plasma membrane creates a barrier which makes ____________ = creates energy (DAM EXAMPLE). - Where do bacteria has ATPase (used to make ATP)?
- selective permeability - ATP - chromatophores - alcohols, quaternary ammonium (detergents), and polymyxin antibiotics - concentration gradients - on outer membrane
Estimating Bacterial Numbers by Indirect Methods: - _________: measurement of cloudiness with a spectrophotometer. * in the light method, cell _______ the light. So _______ cells = less light through. - ________: amount of metabolic product is proportional to the number of bacteria. * how is this measured? - ________: bacteria are filtered, dried, and weighed; used for ___________ organisms.
- turbidity * reflect/ more - metabolic activity * measure the amount of waste products/ measure the before and after nutrients - dry weight/ filamentous
The Terminology of Microbial Control: - ________: refers to bacterial contamination. - _______: is the absence of significant contamination. * aseptic surgery techniques prevent the microbial contamination of _______. - _______: removing and destroying all microbial life. - _______: killing C. botulinum endospores from canned goods. * what interferes with endospore formation? - _______: destroying harmful microorganisms (nonliving surfaces). - _______: destroying harmful microorganisms from living tissue. - _______: the mechanical removal of microbes from a limited area (reducing microbial count, not ____________) - ______: lowering microbial counts on eating utensils to safe levels. - ______: treatments that kill microbes. - ______: inhibiting, not killing, microbes. - We want to be able to ________ the growth of microbes!!!! - cide = _______ - stasis = _______
- sepsis - asepsis * wound - sterilization - commercial sterilization * nitrites and nitrates - disinfection - antisepsis - degerming (sterilization) - sanitization - biocide (germicide) - bacteriostasis - control - killing - stationary = interfering but not killing
Simple Stains: - Simple stain: use of a ________. - Highlights the entire microorganism to visualize _______ and ______. - What are the three common basic dyes? - A _________ may be used to hold the stain or coat the specimen to enlarge it. * _______ is commonly used as a mordant in gram staining.
- simple basic dye - cell shapes and structures - crystal violet, methylene blue, and safranin (red) - mordant * iodine
- __________: movement of a solute from an area of high concentration to an area of low concentration. * continues until molecules reach _________. * with this process, large (polar) ions can't move through, but what can diffuse through the membrane?
- simple diffusion * equilibrium * O2, CO2, and water
Oxygen: - ___________: boosted to a higher-energy state and is reactive. - __________: (O2-): * O2- + O2- + 2H+ --(enzyme?)--> H2O2 + O2 - _________: (O2 2-): * 2H2O2 --(enzyme?)--> 2H2O + O2 (hydrogen peroxide) * H2O2 + 2H+ --(enzyme?)--> 2H2O - _______: (OH-) - All of the enzymes on here are found in bacteria in order to get rid of _________.
- singlet oxygen - superoxide radicals: * superoxide dismutase (SOD) - peroxide anion: * catalase * peroxidase - hydroxyl radical - free radicals
Biofilms: - Microbes attach to ______ surfaces and grow into masses (are everywhere!) - They will grow on rocks, pipes, teeth, and medical implants. - Biofilms can cause ________ and are often resistant to _________ (exchange nutrients between each other!)
- solid - infections/ antibiotics
Scanning Acoustic Microscopy: - Measures ________ that are reflected back from a specimen. - Used to study cells __________. - Resolution of ______ (things smaller than this we can't see).
- sound waves - attached to surfaces (like biofilms) - 1 um
The Debate over Spontaneous Generation: - Occurred at the same time as Hooke and Leeuwenhoek discovers. - __________: the hypothesis that life arises from nonliving matter; a "vital force" is necessary for life. - _________: the hypothesis that living cells arise only from preexisting living cells.
- spontaneous generation - biogenesis
Arrangement of Bacillus Bacterial Cells: - Include: single bacillus, coccobacillus, diplobacillus, and streptobacillus. - What arrangement can bacillus bacteria not be? Why?
- staphylo-/ because they don't divide along their long axis
Chemical Food Preservatives: - ________ prevents wine spoilage. - Organic acids: * inhibits _________. * sorbic acid, benzoic acid, and calcium propionate prevent molds in __________. - __________ prevent endospore germination.
- sulfur dioxide * metabolism * acidic foods - nitrites and nitrates
The Requirements for Growth: - The 3 major physical requirements that are critical when growing bacteria include? - The 5 chemical requirements to consider when growing bacteria include?
- temperature, pH, and osmotic pressure - carbon/ nitrogen, sulfur, and phosphorus/ trace elements/ oxygen/ and organic growth factors
Endoplasmic Reticulum: - Folded ______ network: - _________: studded with ribosomes; sites of protein synthesis. - ________: no ribosomes; synthesizes cell membranes, fats, and hormones.
- transport - rough ER - smooth ER
Scanning Tunneling Microscopy: - Uses a _______ to scan a specimen and reveal details of its surface. - Resolution of _______ of an atom - Drag across surface (like a record player)
- tungsten probe - 1/100
Transmission Electron Microscopy: - A beam of electrons passes through _______ sections of a specimen, then through an ________ lens, then focused on a ________ lens. - Specimens may be stained with _________ for contrast. - Magnifies objects _______ to _______; resolution of ______. - ____ resolution and magnification. - Do not look directly at sample = look at a _______.
- ultrathin/ electromagnetic/ projector - heavy metal salts - 10000 - 100000x/ 10 pm - high - viewing screen
Given what you have learned from the design of Pasteur's experiment, which of the following scenarios would be considered an aseptic technique? Select all that apply! - using a Bunsen burner (flame) to heat a wire inoculating loop prior to use - allowing sterile solutions to be openly exposed to the air - wearing gloves when handling sterile laboratory equipment - blowing on heated, sterile surfaces with your mouth in order to facilitate cooling - taking steps to prevent contaminants from entering sterile solutions
- using a Bunsen burner (flame) to heat a wire inoculating loop prior to use - wearing gloves when handling sterile laboratory equipment - taking steps to prevent contaminants from entering sterile solutions
- _______: is the study of viruses. - _________ in 1892 and ________ in 1935 discovered the cause of mosaic disease of tobacco as a virus. - _______ microscopes have made it possible to study the structure of viruses in detail.
- virology - Dmitri Iwanowski and Wendall Stanley - electron
Direct Microscopic Count: - _______ of a bacterial suspension placed on a slide. - Average number of bacteria per _______ is calculated. - Uses a special ________ counter. - Number of bacteria = __________.
- volume - viewing field - Petroff-Hausser - number of cells counted/ volume of area counted
Acid-Fast Stain: - Binds only to bacteria that have a ______ material (_________ = inhibits crystal violet and safranin of gram stain) in their cell walls, which is not decolorized by ________. - Used for the identification of ______ and _______. - What is one common disease that needs this type of stain? - What is the end color of acid-fast bacteria vs. non-acid-fast bacteria. - Does not use what step that gram stains use?
- waxy (mycolic acid)/ acid-alcohol - mycobacterium and nocardia - tuberculosis - red vs. blue - mordant
If you begin with 6 bacterial cells how many cells will you have after 3 rounds of division?
48 cells
Proof that a microbe could cause disease was provided by A) Pasteur. B) Lister. C) Koch. D) Wasserman. E) Semmelweis.
C) Koch.
What is the purpose of a counterstain in the acid-fast stain?
A counterstain stains the colorless non-acid-fast cells so that they are easily seen through a microscope (blue color)
All of the following substances are effective against nonenveloped viruses EXCEPT A) alcohol. B) chlorine. C) ethylene oxide. D) ozone. E) None of the answers is correct; all of these are equally effective against nonenveloped viruses.
A) alcohol.
8) Which of the following places the steps in the correct sequence? 1-Staining 2-Making a smear 3-Fixing A) 2-3-1 B) 1-3-2 C) 3-2-1 D) 1-2-3 E) The order is unimportant.
A) 2-3-1
6) Which of the following is NOT true regarding the acid-fast stain? A) If cells are acid-fast, they are gram-negative. B) It is used to identify members of the genus Mycobacterium. C) Non-acid-fast microbes appear blue in a completed acid-fast stain. D) Acid-fast cells appear red in a completed acid-fast stain. E) Acid-fast cells retain the primary dye after treatment with acid-alcohol.
A) If cells are acid-fast, they are gram-negative.
The use of phenol (carbolic acid) as a wound disinfectant was first practiced by A) Lister. B) Semmelweis. C) Pasteur. D) Holmes. E) Koch.
A) Lister.
The arguments supporting spontaneous generation were finally disproved by A) Louis Pasteur. B) Francesco Redi. C) Rudolf Virchow. D) John Needham. E) Lazzaro Spallanzani.
A) Louis Pasteur.
Which of the following best describes the pattern of microbial death? A) The cells in a population die at a constant rate. B) All the cells in a culture die at once. C) Not all of the cells in a culture are killed. D) The pattern varies depending on the antimicrobial agent. E) The pattern varies depending on the species.
A) The cells in a population die at a constant rate.
Which step in the Gram stain is the critical step in differentiating gram-positive cells from gram-negative cells? A) alcohol-acetone B) iodine C) safranin D) crystal violet
A) alcohol-acetone
Which of the following pairs of terms is mismatched? A) bacteriostatic — kills vegetative bacterial cells B) germicide — kills microbes C) virucide — inactivates viruses D) sterilant — destroys all living microorganisms E) fungicide — kills yeasts and molds
A) bacteriostatic — kills vegetative bacterial cells
All of the following substances are used to preserve foods EXCEPT A) biguanides. B) nisin. C) potassium sorbate. D) sodium nitrite. E) calcium propionate.
A) biguanides.
The addition of which of the following to a culture medium will neutralize acids? A) buffers B) sugars C) pH D) heat E) carbon
A) buffers
Which structure acts like an "invisibility cloak" and protects bacteria from being phagocytized? A) capsule B) slime layer C) cell wall D) fimbriae E) cell membrane
A) capsule
Which of the following is NOT found in mitochondria and prokaryotes? A) cell wall B) binary fission C) circular chromosome D) 70S ribosomes E) ATP-generating mechanism
A) cell wall
In bacteria, photosynthetic pigments are found in A) chromatophores. B) ribosomes. C) cytoplasm. D) chloroplasts. E) mesosomes.
A) chromatophores.
In which of the following situations would Koch's postulates be utilized? A) determination of the cause of a patient's illness in a hospital microbiology lab B) development of a new antibiotic in a pharmaceutical lab C) determination of the cause of cancer in a patient D) formulation of a vaccine against a new pathogen in a genetic engineering lab E) whenever the scientific method is used to investigate a microbiological problem
A) determination of the cause of a patient's illness in a hospital microbiology lab
An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n) A) disinfectant. B) antiseptic. C) aseptic. D) fungicide. E) virucide.
A) disinfectant.
The term aerotolerant anaerobe refers to an organism that A) does not use oxygen but tolerates it. B) is killed by oxygen. C) tolerates normal atmospheric nitrogen gas levels. D) requires less oxygen than is present in air. E) requires more oxygen than is present in air.
A) does not use oxygen but tolerates it.
The microbial process of converting sugars to alcohol is known as A) fermentation. B) pasteurization. C) tyndallization. D) lyophilization. E) alcoholism.
A) fermentation.
Which of the following is NOT associated with viruses? A) organelles B) nucleic acid C) envelope D) spikes E) capsid
A) organelles
Which microscope takes advantage of differences in the refractive indexes of cell structures? A) phase-contrast microscope B) compound light microscope C) darkfield microscope D) electron microscope E) fluorescence microscope
A) phase-contrast microscope
Which microscope is best used for observing the surfaces of intact cells and viruses? A) scanning electron microscope B) phase-contrast microscope C) fluorescence microscope D) brightfield microscope E) darkfield microscope
A) scanning electron microscope
You are studying a cell structure that is approximately 100 nm in size. Which of the following provides the lowest magnification you can use to see this structure? A) scanning electron microscope B) transmission electron microscope C) phase-contrast microscope D) darkfield microscope E) brightfield microscope
A) scanning electron microscope
2) What structure does light pass through after leaving the condenser in a compound light microscope? A) specimen B) ocular lens C) objective lens D) illuminator
A) specimen
The antimicrobial activity of chlorine is due to which of the following? A) the formation of hypochlorous acid B) the formation of hydrochloric acid C) the formation of ozone D) the formation of a hypochlorite ion E) disruption of the plasma membrane
A) the formation of hypochlorous acid
16) A virus measures 100 nm in length. What is its length in μm? A) 0.01 μm B) 1 μm C) 0.001 μm D) 10 μm E) .1 μm
E) .1 μm
Which microscope uses two beams of light to produce a three-dimensional color image? A) fluorescence microscope B) DIC microscope C) phase-contrast microscope D) electron microscope E) darkfield microscope
B) DIC microscope
1) Which of the following is NOT equal to 1 mm? A) 10-3 m B) 100 μm C) 10 6 nm D) 0.1 cm E) 0.001 m
B) 100 μm
Most fungi grow best at pH A) 1. B) 5. C) 7. D) 9. E) 14.
B) 5.
Who is credited with first observing microorganisms? A) Robert Hooke B) Anton van Leeuwenhoek C) Robert Koch D) Louis Pasteur E) Carolus Linnaeus
B) Anton van Leeuwenhoek
Which of the following pairs is mismatched? A) Ag — wound dressings B) alcohols — open wounds C) CuSO4— algicide D) H2O2— open wounds E) organic acids — food preservation
B) alcohols — open wounds
Pathogenic bacteria isolated from the respiratory or intestinal tracts of humans are A) strict aerobes that grow best in candle jars. B) capnophiles that grow best in carbon dioxide incubators. C) facultative anaerobes that require reducing media for growth. D) strict aerobes that grow best in reducing media. E) capnophiles that prefer highly oxygenated growth conditions.
B) capnophiles that grow best in carbon dioxide incubators.
A culture medium consisting of agar, peptone, and beef heart is a A) chemically defined medium. B) complex medium. C) selective medium. D) differential medium. E) reducing medium.
B) complex medium.
Biogenesis refers to the A) spontaneous generation of organisms from nonliving matter. B) development of life forms from preexisting life forms. C) development of aseptic technique. D) germ theory of disease.
B) development of life forms from preexisting life forms.
In using this microscope, the observer does NOT look directly at an image through a lens. A) phase-contrast microscope B) electron microscope C) fluorescence microscope D) compound light microscope E) darkfield microscope
B) electron microscope
Which of the following have a cell wall? A) mycoplasmas B) fungi C) protoplasts D) L forms E) animal cells
B) fungi
Oxidizing agents include all of the following EXCEPT A) chlorine. B) glutaraldehyde. C) hydrogen peroxide. D) iodine. E) ozone.
B) glutaraldehyde.
During which growth phase will gram-positive bacteria be most susceptible to penicillin? A) lag phase B) log phase C) death phase D) stationary phase E) The culture is equally susceptible during all phases.
B) log phase
Which of the following does NOT achieve sterilization? A) dry heat B) pasteurization C) autoclave D) supercritical fluids E) ethylene oxide
B) pasteurization
In a hypertonic solution, a bacterial cell will typically A) burst. B) plasmolyze. C) osmolyze. D) lyse. E) stay the same.
B) plasmolyze.
The difference between simple diffusion and facilitated diffusion is that facilitated diffusion A) moves materials from a lower to a higher concentration. B) requires transporter proteins. C) does not require ATP. D) requires ATP. E) moves materials from a higher to a lower concentration.
B) requires transporter proteins.
Which of the following is the best definition of generation time? A) the length of time needed for lag phase B) the length of time needed for a cell to divide C) the minimum rate of doubling D) the duration of log phase E) the time needed for nuclear division
B) the length of time needed for a cell to divide
Which of the following pairs of microbe classification terms and optimal growth temperatures is mismatched? A) psychrotroph — growth at 0°C B) thermophile — growth at 37°C C) mesophile — growth at 25°C D) psychrophile — growth at 15°C E) hyperthermophiles — growth at 85°C
B) thermophile — growth at 37°C
Which of the following is an organic growth factor? A) glucose B) vitamin B1 C) peptone D) Mg+2 E) H2O
B) vitamin B1
CHAPTER 1: THE MICROBIAL WORLD AND YOU
BEGINS HERE
CHAPTER 3
BEGINS HERE
CHAPTER 4
BEGINS HERE
CHAPTER 6
BEGINS HERE
CHAPTER 6 & 7: QUIZ AND TEST QUESTIONS
BEGINS HERE
CHAPTER 7: THE CONTROL OF MICROBIAL GROWTH
BEGINS HERE
CHAPTERS 3 & 4: QUIZ & TEST QUESTIONS
BEGINS HERE
4) Which of the following places the steps of the Gram stain in the correct order? 1-Alcohol-acetone 2-Crystal violet 3-Safranin 4-Iodine A) 2-1-4-3 B) 1-3-2-4 C) 2-4-1-3 D) 4-3-2-1 E) 1-2-3-4
C) 2-4-1-3
Most bacteria grow best at pH A) 1. B) 5. C) 7. D) 9. E) 14.
C) 7.
Three cells with generation times of 60 minutes are inoculated into a culture medium. How many cells are there after 5 hours? A) 900 B) 180 C) 96 D) 32 E) 15
C) 96
The biosafety level (BSL) for a clinical microbiology laboratory working with potentially airborne pathogens, such as tuberculosis bacteria, is A) BSL-1. B) BSL-2. C) BSL-3. D) BSL-4.
C) BSL-3.
Who was the first scientist to pursue a "magic bullet" that could be used to treat infectious disease? A) Jenner B) Pasteur C) Ehrlich D) Lister E) Semmelweis
C) Ehrlich
Which of the following disinfectants acts by disrupting the plasma membrane? A) soaps B) aldehydes C) bisphenols D) halogens E) heavy metals
C) bisphenols
Classification of organisms into three domains is based on A) the presence of a cell wall. B) the number of cells in the organism. C) cellular organization. D) nutritional requirements. E) cellular proteins.
C) cellular organization.
Which of the following pairs is mismatched? A) endoplasmic reticulum internal transport B) Golgi complex secretion C) centrosome food storage D) lysosome digestive enzymes E) mitochondria ATP production
C) centrosome food storage
Which of the following substances is used for surgical hand scrubs? A) phenol B) chlorine bleach C) chlorhexidine D) soap E) glutaraldehyde
C) chlorhexidine
Which of the following structures is NOT found in some prokaryotic cells? A) pilus B) flagellum C) cilium D) peritrichous flagella E) axial filament
C) cilium
The preservation of beef jerky from microbial growth relies on which method of microbial control? A) filtration B) lyophilization C) desiccation D) ionizing radiation E) supercritical CO2
C) desiccation
Which microscope is used to see detail of a 300-nm virus? A) darkfield microscope B) phase-contrast microscope C) electron microscope D) DIC microscope E) fluorescence microscope
C) electron microscope
Which of the following chemical agents is used for sterilization? A) alcohol B) phenolics C) ethylene oxide D) chlorine E) soap
C) ethylene oxide
The data in Table 6.2 indicate that S. aureus is a(n) A) mesophile. B) facultative anaerobe. C) facultative halophile. D) aerobe. E) halophile.
C) facultative halophile.
Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes? A) lyophilization B) nonionizing radiation C) freezing D) ionizing radiation E) pasteurization
C) freezing
Which of the following is the best method to sterilize heat-labile solutions? A) dry heat B) autoclave C) membrane filtration D) pasteurization E) freezing
C) membrane filtration
Which one of the following is most resistant to chemical biocides? A) gram-negative bacteria B) gram-positive bacteria C) mycobacteria D) protozoan cysts E) viruses with lipid envelopes
C) mycobacteria
Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of A) plasmolysis. B) inhibition of molecular transport. C) osmotic lysis. D) decreased synthesis of peptidoglycan. E) cell shrinkage.
C) osmotic lysis.
The source of nutrients in nutrient agar is A) agar. B) gelatin. C) peptone and beef extract. D) peptone and NaCl. E) agar and NaCl.
C) peptone and beef extract.
Which enzyme catalyzes the reaction: H2O2 + 2H+ → 2H2O? A) catalase B) oxidase C) peroxidase D) superoxide dismutase
C) peroxidase
Which microscope is used to see internal structures of cells in a natural state? A) darkfield microscope B) fluorescence microscope C) phase-contrast microscope D) electron microscope E) compound light microscope
C) phase-contrast microscope
Which of the following is an advantage of the direct microscopic count? A) can readily count organisms that are motile B) can easily distinguish live from dead cells C) requires no incubation time D) sample volume is unknown E) requires a large number of cells
C) requires no incubation time
Which microscope can be used to visualize DNA or botulinum toxin? A) scanning electron microscope B) compound light microscope C) scanning tunneling microscope D) confocal microscope E) phase-contrast microscope
C) scanning tunneling microscope
Which of the following pairs is mismatched? A) darkfield microscope —uses visible light B) fluorescence microscope —uses a fluorescent light C) scanning tunneling microscope —allows visualization of atoms D) scanning electron microscope —produces a three-dimensional image E) confocal microscope —produces a three-dimensional image
C) scanning tunneling microscope —allows visualization of atoms
Where are phospholipids most likely found in a prokaryotic cell? A) flagella B) around organelles C) the plasma membrane D) ribosomes E) the plasma membrane and around organelles
C) the plasma membrane
Assume you inoculated 100 cells, with a generation time of 20 minutes, into 100 ml of nutrient broth. You then inoculated 100 cells of the same species into 200 ml of nutrient broth. After incubation for 4 hours, you can reasonably expect to have A) more cells in the 100 ml. B) more cells in the 200 ml. C) the same number of cells in both. D) The answer cannot be determined based on the information provided.
C) the same number of cells in both.
The following is true of quarternary ammonium compounds EXCEPT A) they are non-toxic at lower concentrations. B) they are tasteless. C) they are effective when combined with soaps. D) they are stable. E) they may be an ingredient in mouthwash.
C) they are effective when combined with soaps.
Which microscope is used to see intracellular detail in a living cell? A) brightfield microscope B) fluorescence microscope C) two-photon microscope D) atomic force microscope E) transmission electron microscope
C) two-photon microscope
Thirty-six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample? A) 4 per milliliter B) 9 per milliliter C) 18 per milliliter D) 36 per milliliter E) 72 per milliliter
D) 36 per milliliter
An experiment began with 4 cells and ended with 128 cells. How many generations did the cells go through? A) 64 B) 32 C) 6 D) 5 E) 4
D) 5
A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained A) 54 cells per milliliter. B) 540 cells per milliliter. C) 5,400 cells per milliliter. D) 54,000 cells per milliliter. E) 540,000 cells per milliliter.
D) 54,000 cells per milliliter.
The formal system for classifying and naming organisms was developed by A) Robert Koch. B) Ignaz Semmelweis. C) Aristotle. D) Carolus Linnaeus. E) Louis Pasteur.
D) Carolus Linnaeus.
If cells are grown in media containing amino acids labeled with radioactive nitrogen (15N), most of the radioactivity will be found in the cells' A) DNA. B) proteins. C) phospholipids. D) DNA and proteins. E) DNA and phospholipids.
D) DNA and proteins.
Which of the following is a limitation of the autoclave? A) It requires an excessively long time to achieve sterilization. B) It cannot inactivate viruses. C) It cannot kill endospores. D) It cannot be used with heat-labile materials. E) It cannot be used with glassware.
D) It cannot be used with heat-labile materials.
How do spirochetes and spirilla differ? A) Spirochetes have a rigid, corkscrew shape while spirilla are helical and more flexible. B) Spirochetes and spirilla are basically the same organisms and the terms can be used interchangeably. C) Spirilla are found in chains of cells whereas spirochetes exist as individual cells. D) Spirilla have an external flagella but spirochetes have axial filaments. E) Spirochetes do not have a cell wall but spirilla do.
D) Spirilla have an external flagella but spirochetes have axial filaments.
What will happen if a bacterial cell is placed in distilled water with lysozyme? A) The cell will plasmolyze. B) Lysozyme will diffuse into the cell. C) Water will leave the cell. D) The cell will undergo osmotic lysis. E) No change will result; the solution is isotonic.
D) The cell will undergo osmotic lysis.
Which of the following treatments is the most effective for controlling microbial growth? A) 63°C for 30 minutes B) 72°C for 15 seconds C) 140°C for 4 seconds D) They are equivalent treatments. E) None of the answers is correct.
D) They are equivalent treatments.
Which of the following statements best describes what happens when a bacterial cell is placed in a solution containing 5 percent NaCl? A) Water will move into the cell. B) Sucrose will move into the cell from a higher to a lower concentration. C) The cell will undergo osmotic lysis. D) Water will move out of the cell. E) No change will result; the solution is isotonic.
D) Water will move out of the cell.
Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder) are susceptible to infections because A) injected solutions are contaminated. B) their immune systems are weakened. C) infections can be transmitted from other people. D) biofilms develop on catheters. E) bacteria cause infections.
D) biofilms develop on catheters.
Simple staining is often necessary to improve contrast in which microscope? A) phase-contrast microscope B) fluorescence microscope C) darkfield microscope D) compound light microscope E) electron microscope
D) compound light microscope
You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume that the cell A) lives in an extreme environment. B) has 9 pairs + 2 flagella. C) has a mitochondrion. D) has a cell wall. E) has cilia.
D) has a cell wall.
Salts and sugars work to preserve foods by creating a A) depletion of nutrients. B) hypotonic environment. C) lower osmotic pressure. D) hypertonic environment. E) lower pH.
D) hypertonic environment.
Ethylene oxide A) is a good antiseptic. B) is not sporicidal. C) requires high heat to be effective. D) is a sterilizing agent. E) is the active chemical in household bleach.
D) is a sterilizing agent.
Which of the following is NOT a direct method to measure microbial growth? A) direct microscopic count B) standard plate count C) filtration on a support membrane followed by incubation on medium D) metabolic activity E) most probable number (MPN)
D) metabolic activity
All of the following are methods of food preservation EXCEPT A) desiccation. B) high pressure. C) ionizing radiation. D) microwaves. E) osmotic pressure.
D) microwaves.
Which of the following organelles most closely resembles a prokaryotic cell? A) Golgi complex B) cell wall C) nucleus D) mitochondrion E) vacuole
D) mitochondrion
Fungal infections are studied by A) virologists. B) bacteriologists. C) parasitologists. D) mycologists. E) herpetologists.
D) mycologists.
7) The purpose of a mordant in the Gram stain is to A) remove the simple stain. B) make gram-negative cells visible. C) make the flagella visible. D) prevent the crystal violet from leaving the cells. E) make the bacterial cells larger.
D) prevent the crystal violet from leaving the cells.
In microscopy, the term resolution A) is only observed in stained specimens. B) is improved when longer wavelengths of light are employed. C) refers to magnification when using the electron microscope. D) refers to the ability to distinguish fine structure and detail in a specimen. E) is the same as the total magnification of a specimen.
D) refers to the ability to distinguish fine structure and detail in a specimen.
5) Which of the following pairs is mismatched? A) alcohol-acetone — decolorizer B) crystal violet — basic dye C) carbolfuchsin — basic dye D) safranin — acid dye E) iodine — mordant
D) safranin — acid dye
Which of the following is NOT useful for observing living cells? A) darkfield microscope B) brightfield microscope C) scanning acoustic microscope D) scanning electron microscope E) phase-contrast microscope
D) scanning electron microscope
Which disease has been eliminated through the use of vaccines? A) tuberculosis B) measles C) rubella D) smallpox E) influenza
D) smallpox
Which enzyme catalyzes the reaction: O2- + O2- + 2H+ → H2O2 + O2? A) catalase B) oxidase C) peroxidase D) superoxide dismutase
D) superoxide dismutase
Oxygen crosses a plasma membrane A) by osmosis. B) through facilitated diffusion. C) through porins. D) through simple diffusion. E) with the help of a nonspecific transporter.
D) through simple diffusion.
A gram-positive bacteria suddenly acquires resistance to the antibiotic methicillin. This trait most likely occurred due to A) binary fission. B) meisosis. C) conjugation. D) transformation. E) transduction.
D) transformation.
Which of the following regarding antimicrobial control agents is FALSE? A) Contaminating organic debris such as blood or sputum will decrease effectiveness. B) Some agents kill by denaturing microbial cell proteins. C) Some agents affect microbial cell membranes by dissolving lipids. D) Some agents are utilized as both an antiseptic and a disinfectant. E) A true antimicrobial control agent is equally effective against both bacteria and viruses.
E) A true antimicrobial control agent is equally effective against both bacteria and viruses.
Which of the following statements about gram-negative cell walls is FALSE? A) They are toxic to humans. B) They have an extra outer layer composed of lipoproteins, lipopolysaccharides, and phospholipids. C) Their Gram reaction is due to the outer membrane. D) They protect the cell in a hypotonic environment. E) They are sensitive to penicillin.
E) They are sensitive to penicillin.
You find colorless areas in cells in a gram-stained smear. What should you apply next? A) an acid-fast stain B) a capsule stain C) a flagella stain D) a simple stain E) an endospore stain
E) an endospore stain
Which of the following are NOT energy reserves? A) polysaccharide granules B) sulfur granules C) metachromatic granules D) lipid inclusions E) carboxysomes
E) carboxysomes
This microscope produces an image of a light cell against a dark background; internal structures are NOT visible. A) electron microscope B) compound light microscope C) phase-contrast microscope D) fluorescence microscope E) darkfield microscope
E) darkfield microscope
Which microscope uses visible light? A) scanning acoustic microscope B) confocal microscope C) fluorescence microscope D) scanning electron microscope E) differential interference contrast microscope
E) differential interference contrast microscope
Which microscope is used to observe a specimen that emits light when illuminated with an ultraviolet light? A) electron microscope B) darkfield microscope C) compound light microscope D) phase-contrast microscope E) fluorescence microscope
E) fluorescence microscope
Which of the following results in lethal damage to nucleic acids? A) heat B) radiation C) certain chemicals D) heat and radiation E) heat, radiation, and some chemicals
E) heat, radiation, and some chemicals
An iodophor is a(n) A) phenol. B) agent that reduces oxygen. C) quaternary ammonium compound. D) form of formaldehyde. E) iodine mixed with a surfactant.
E) iodine mixed with a surfactant.
The DNA found in most bacterial cells A) utilizes histones for chromosomal packaging. B) is found in multiple copies. C) is surrounded by a nuclear membrane. D) is linear in structure. E) is circular in structure.
E) is circular in structure.
Bacteria are a commonly used organism for studies of genetic material in the research laboratory. The nucleic acids must first be isolated from the cells for these studies. Which of the following would most likely be used to lyse the bacterial cells for nucleic acid isolation? A) polymixins B) water C) alcohol D) mycolic acid E) lysozyme
E) lysozyme
Which of the following elements is NOT correctly matched with its cellular function? A) nitrogen — needed for amino acid synthesis B) phosphorus — incorporated into nucleic acids C) sulfur — used for synthesis of thiamin and biotin D) magnesium and potassium — required as cofactors for enzymes E) phosphorus — used for production of carbohydrates.
E) phosphorus — used for production of carbohydrates.
If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar? A) bleach B) boiling for one hour C) hydrogen peroxide D) oven at 121°C for one hour E) pressure cooker at 121°C for 15 minutes
E) pressure cooker at 121°C for 15 minutes
Which microscope is most useful for visualizing a biofilm? A) phase-contrast microscope B) compound light microscope C) fluorescence microscope D) transmission electron microscope E) scanning acoustic microscope
E) scanning acoustic microscope
Microorganisms are involved in each of the following processes EXCEPT A) infection. B) decomposition of organic material. C) O2 production. D) food production. E) smog production.
E) smog production.
Where are phospholipids most likely found in a eukaryotic cell? A) ribosomes B) the plasma membrane C) surrounding flagella D) around organelles E) the plasma membrane, around organelles, and surrounding flagella
E) the plasma membrane, around organelles, and surrounding flagella
Which microscope is used to observe viruses and the internal structure of thinly sectioned cells? A) brightfield microscope B) fluorescence microscope C) darkfield microscope D) scanning electron microscope E) transmission electron microscope
E) transmission electron microscope
Starch is readily metabolized by many cells, but a starch molecule is too large to cross the plasma membrane. How does a cell obtain the glucose molecules from a starch polymer? How does the cell tranposrt these glucose molecules across the plasma membrane?
Endocytosis occurs to engulf and take in a starch polymer. The cell uses active transport to move the glucose molecules across the plasma membrane
Why is a mordant used in the Gram stain? In the flagella stain?
In a Gram stain, the mordant combines with the basic dye to form a complex that will not wash out of gram-positive cells. In a flagella stain, the mordant accumulates on the flagella so that they can be seen with a light microscope.
What is the purpose of a decolorizer in the Gram stain? In the acid-fast stain?
In the Gram stain, the decolorizer removes the color from gram-negative cells. In the acid-fast stain, the decolorizer removes the color from the non-acid-fast cells.
What was instrumental in DISPROVING spontaneous generation?
Pasteur's experiments using a swan-necked flask that prevented microbes from entering flasks open to the air.
In Figure 6.1, which line shows the growth of an obligate aerobe incubated anaerobically? a b c
c
In Figure 6.1,which line best depicts an obligate anaerobe in the presence of O2? a b c
c
Contaminated hospital equipment represents a difficult environment to control harmful microbial growth. Why is this?
The cell wall of gram-negative bacteria is especially resistant to many chemicals that are used destroy microbes.
What would happen if the septum did not form during binary fission?
The parent cell would now have two copies of the chromosome.
For the three types of media in Table 6.1, which medium (or media) is/are chemically defined? a b c a and b a and c
a
In Table, 6.1, in which medium (or media) would an autotroph grow? a b c a and b a and c
a
Which statement best describes what happens when a gram-positive bacterium is placed in an aqueous solution of lysozyme and 10% sucrose? a) No change will result; the solution is isotonic b) Water will move into the cell c) Water will move out of the cell d) the cell will undergo osmotic lysis e) Sucrose will move into the cell from an area of higher concentration to one of lower concentration
a) No change will result; the solution is isotonic
You have isolated a motile, gram-positive cell with no visible nucleus. You can assume this cell has: a) ribosomes b) mitochondria c) an endoplasmic reticulum d) a Golgi complex e) all of the above
a) ribosomes
Which of the following is NOT visible through a compound light microscope? a. 0.02-µm ribosome b. 1.5-mm tick c. 5-µm nucleus d. 15-µm white blood cell
a. 0.02-µm ribosome
Most bacteria are in the __________ size range. a. 1-10 micrometer b. 1-10 nanometer c. 2-5 millimeter d. 0.5-1 centimeter
a. 1-10 micrometers
If you use a compound light microscope, a 2-µm bacterial cell is best seen at which magnification? a. 1000× b. 10× c. 100× d. 400×
a. 1000x
The maximum magnification of a compound microscope is (a)_____; that of an electron microscope, (b)______. The maximum resolution of a compound microscope is (c)______; that of an electron microscope, (d)______. One advantage of a scanning electron microscope over a transmission electron microscope is (e)______.
a. 2,000X b. 100,000X c. 0.2μm d. 0.0025μm e. Seeing three-dimensional detail.
Which of the following is true of biofilms? a. A biofilm is a complex aggregation of microbes. b. A biofilm is the layer of material examined on a microscope slide. c. Biofilms are never found in humans. d. Biofilms are weak aggregations of microbes that are easily removed from surfaces.
a. A biofilm is a complex aggregation of microbes.
Consider the following situations, and determine when a simple stain should be used instead of a Gram stain. a. A microbiologist is trying to determine whether an organism has flagella. b. An unknown species of bacteria is being characterized and identified. c. A wound specimen is being examined. d. A specimen is being examined in which the presence of multiple species of bacteria is suspected.
a. A microbiologist is trying to determine whether an organism has flagella.
Which of the following is an example of a healthcare-associated infection (HAI)? a. A patient develops a Pseudomonas infection during treatment in a burn unit. b. A child visits a clinic with a suspected case of strep throat. c. A man enters the hospital with a suspected rabies infection due an animal bite. d. A cancer patient is admitted to the hospital with complications.
a. A patient develops a Pseudomonas infection during treatment in a burn unit.
Which of the following processes occurs in bacterial plasma membranes but NOT in eukaryotic plasma membranes? a. ATP synthesis b. Active transport c. Protein synthesis d. Facilitated diffusion e. RNA synthesis
a. ATP synthesis
The biosafety level (BSL) for most introductory microbiology laboratories is a. BSL-1. b. BSL-2. c. BSL-3. d. BSL-4.
a. BSL-1.
Which level of biosafety (BSL) is appropriate for handling organisms that present the highest risk level for infection and the lowest success rate for prevention and treatment? a. BSL-4 b. BSL-1 c. BSL-2 d. BSL-3
a. BSL-4
Which of the following is true of bacteria that have atypical cell walls, such as those in the genus Mycoplasma? a. Bacteria with atypical cell walls are generally among the smallest bacteria that can reproduce outside a host cell. b. These atypical bacteria have the same plasma membrane typical of bacteria. c. These atypical bacteria usually stain gram-negative. d. Although small, these atypical bacteria cannot pass through most filters.
a. Bacteria with atypical cell walls are generally among the smallest bacteria that can reproduce outside a host cell.
Which one of the following substances is effective against bacterial endospores? a. Chlorine b. Mercury c. Bisphenols d. Quaternary compounds
a. Chlorine
Which type of microscope would be best to use to observe each of the following? a. a stained bacterial smear b. unstained bacterial cells: the cells are small, and no detail is needed c. unstained live tissue when it is desirable to see some intracellular detail d. a sample that emits light when illuminated with ultraviolet light e. intracellular detail of a cell that is 1μm long f. unstained live cells in which intracellular structures are shown in color
a. Compound Light Microscope b. Darkfield Microscope c. Phase-Contrast Microscope d. Fluorescence Microscope e. Electron Microscope f. Differential Interference Contrast Microscope
Which of the following statements about E.coli is false? a. E.coli was the first disease causing bacterium identified by Koch b. E.coli is part of the normal microbiota of humans c. E.coli is beneficial in human intestines d. E. coli gets nutrients from intestinal contents. e. None of the above
a. E. coli was the first disease causing bacterium identified by Koch
Which of the following staining procedures is correctly matched with the principal use for that particular stain? a. Endospore stain to distinguish dormant structures formed during adverse environmental conditions b. Acid-fast stain for microbes with capsules c. Negative stain used to differentiate cell wall components d. Flagella stain used to detect capsules
a. Endospore stain to distinguish dormant structures formed during adverse environmental conditions
Which of the following statements is true? a. Endospores are extremely durable structures that can survive high temperatures. b. Endospores allow a cell to attach to solid surfaces and to surfaces within the host. c. Endospores are reproductive structures. d. One bacterial cell produces many endospores.
a. Endospores are extremely durable structures that can survive high temperatures.
Which one of these chemical treatments kills cells by causing cross-linking of nucleic acids and proteins and inhibits vital cellular functions? a. Ethylene oxide b. Alcohol c. Heavy metals d. Soaps and detergents
a. Ethylene oxide
You contaminate the kitchen counters with Salmonella enterica in chicken blood and expose it to a variety of treatments to study the survival of the bacteria on kitchen surfaces. The following DRT values were obtained: 2.0 minutes at 52°C; 3.7 minutes at pH 2.6; 13.3 minutes with 10 mM hydrogen peroxide; and > 35 days without treatment. Which treatment is most effective against S. enterica? a. Heat (52ºC) b. 10 mM hydrogen peroxide c. Acid (pH 2.6) d. These are equivalent treatments. e. The most effective treatment cannot be determined from the given data.
a. Heat (52ºC)
Pasteur discovered that microbes can cause food spoilage. His solution to protect wine from spoiling was a process called pasteurization, which is based on what principle? a. Heating beer and wine just enough to kill those organisms causing the spoilage b. The destruction of all microbes in the wine c. Filtration of the wine to remove all microbes d. Addition of specific disinfectants and food preservatives that prevent the spoilage
a. Heating beer and wine just enough to kill those organisms causing the spoilage
Which of the following statements about a gram-negative cell wall is FALSE? a. It contains teichoic acid. b. It includes a thin layer of peptidoglycan. c. It functions as an endotoxin. d. It maintains the shape of the cell.
a. It contains teichoic acid.
Which of the following is used to control microbial growth in foods? a. Organic acids b. Alcohols c. Aldehydes d. Heavy metals e. All of the above.
a. Organic acids
When properly subjected to an acid fast stain protocol, bacteria in the genus Mycobacterium appear __________. When using a 10× ocular lens and a 40× objective, the total magnification achieved is __________. a. Red; 400X b. Red; 1000X c. Blue; 1000X d. Purple; 400X
a. Red; 400X
Which of the following statements accurately describes the culture medium necessary for growing an obligate anaerobe, such as Clostridium tetani? a. Reducing media are complex media containing chemicals, such as thioglycolate, that combine with oxygen, creating an anaerobic environment. b. A complex medium is one whose exact chemical composition is known. c. A chemically defined medium is one made up of extracts such as those from yeasts, meat, or plants whose exact chemical composition may vary slightly. d. Nutrient agar contains ingredients that combine with oxygen and remove it, creating an anaerobic environment.
a. Reducing media are complex media containing chemicals, such as thioglycolate, that combine with oxygen, creating an anaerobic environment.
Which of the following correctly describes antisepsis? a. Removal of vegetative microorganisms from living tissue b. Destruction of vegetative microorganisms on inanimate surfaces c. Destruction of all organisms on any surface d. Reduction of microbial cells on eating or drinking utensils
a. Removal of vegetative microorganisms from living tissue
A microscopist is studying the surface pores on a bacterial specimen. Which microscope provides the best three-dimensional surface structure image? a. Scanning electron microscope b. Transmission electron microscope c. Fluorescence microscope d. Brightfield microscope
a. Scanning electron microscope
What is quorum sensing? a. The ability of bacteria in a biofilm to communicate with each other and coordinate their activities b. The ability of bacteria in a biofilm to sense O2 c. The ability of bacteria in a biofilm to use inorganic nitrogen sources d. The ability of bacteria in a biofilm to grow on selective media
a. The ability of bacteria in a biofilm to communicate with each other and coordinate their activities
What will occur if a bacterial cell with a weakened or damaged cell wall is placed in pure water? a. The cell will swell and burst. b. The cell will remain the same size. c. The cell will shrink. d. The cell will form endospores. e. The cell will form a new cell wall.
a. The cell will swell and burst.
Which of the following statements regarding infections involving biofilms is FALSE? a. There is no way to prevent biofilms from developing on surfaces. b. The majority of hospital-acquired infections (nosocomial infections) are related to biofilms. c. Microbes in biofilms are more resistant to antimicrobials than are independent organisms. d. It is estimated that nearly 70% of all infections are caused by biofilms.
a. There is no way to prevent biofilms from developing on surfaces.
In the Gram stain, what is the purpose of the decolorizer? a. To selectively remove stain from cells b. To clean off excess stain c. To wash slides d. To stain gram-negative cells
a. To selectively remove stain from cells
In the figure, which line best illustrates the growth of a facultative anaerobe incubated aerobically? a. a b. b c. c
a. a
In a prokaryotic cell, all of the following are functions of either fimbriae or pili EXCEPT __________. a. protection from phagocytosis or determining the shape of the cell b. transfer of DNA c. formation of biofilms d. attachment to a surface
a. a. protection from phagocytosis or determining the shape of the cell
Which of the following processes requires cellular energy in the form of ATP? a. active transport b. simple diffusion c. osmosis d. facilitated diffusion
a. active transport
Cells may frequently find themselves in an environment with very low extracellular concentrations of substances needed in higher amounts inside the cell. To obtain these needed items, such cells would be most likely to engage in a. active transport. b. facilitated diffusion. c. osmosis. d. simple diffusion.
a. active transport.
Microbes are NOT responsible for __________. a. antibody production b. breaking down wastes c. the synthesis of vitamins d. the synthesis of acetone and alcohol e. oxygen generation via photosynthesis
a. antibody production
Which of the following is an example of bioremediation? a. application of oil degrading bacteria to an oil spill b. application of bacteria to a crop to prevent frost damage c. fixation of gaseous nitrogen into usable nitrogen d. production by bacteria of a human protein such as interferon e. all of the above
a. application of oil degrading bacteria to an oil spill
Which type of microscope uses a metal and diamond probe that is gently forced down along the surface of a specimen? a. Atomic force b. Confocal c. Transmission electron d. Scanning electron e. Scanning tunneling
a. atomic force
Some antimicrobial treatments kill microbes; some inhibit growth. Which term refers to an agent that acts by killing bacteria? a. bactericidal b. homeostatic c. germicidal d. bacteriostatic e. fungicidal
a. bactericidal
Which of the following physical methods of microbial control denatures proteins as a mechanism of action? a. boiling or autoclaving b. incineration c. osmotic pressure d. radiation
a. boiling or autoclaving
Which of the following properties are true of both bacteria and archaea? a. both are characterized as prokaryotes b. both have cell walls composed of peptidoglycan c. both are known to cause disease in humans d. both contain either DNA or RNA e. both bacteria and archaea contain methanogens, extreme halophiles, and extreme thermophiles
a. both are characterized as prokaryotes
Which of the following properties are true of both bacteria and viruses? a. both use a molecule of nucleic acid to determine heredity b. both have cell walls composed of peptidoglycan c. both can replicate using biogenesis d. both are surrounded by a protein coat e. both contain DNA and RNA
a. both use a molecule of nucleic acid to determine heredity
In 1996, scientists described a new tapework parasite that had killed at least one person. The initial examination of the patient's abdominal mass was most likely made using: a. brightfield microscopy b. darkfield microscopy c. electron microscopy d. phase-contrast microscopy e. fluorescence microscopy
a. brightfield microscopy
Which enzyme catalyzes the following reaction? 2H2O2 → 2H2O + O2 a. catalase b. oxidase c. peroxidase d. superoxide dismutase
a. catalase
Looking at the cell of a photosynthetic microorganism, you observe that the chloroplasts are green in brightfield microscopy and red in fluorescent microscopy. You conclude that: a. chlorophyll is fluorescent b. the magnification has distorted the image c. you're not looking at the same structure in both microscopes d. the stain masked the green color e. none of the above
a. chlorophyll is fluorescent
Protozoan motility structures include a. cilia, flagella, and pseudopods. b. cilia c. pseudopods d. cilia and pseudopods only e. flagella
a. cilia, flagella, and pseudopods.
Which of the following types of microscopy provides advantages for viewing live images? a. darkfield microscopy b. fluorescent microscopy c. scanning electron microscopy d. transmission electron microscopy
a. darkfield microscopy
Application of heat to living cells can result in all of the following EXCEPT a. decreased thermal death time. b. breaking of hydrogen bonds. c. damage to nucleic acids. d. alteration of membrane permeability. e. denaturation of enzymes.
a. decreased thermal death time.
The negative stain is used to a. determine cell size. b. visualize endospores. c. visualize fimbriae. d. determine Gram reaction. e. determine flagella arrangement.
a. determine cell size.
During log phase, bacteria are __________. a. dividing at the fastest possible rate b. preparing to divide c. dying and dividing in equal numbers d. dying exponentially
a. dividing at the fastest possible rate
Which of the following findings was essential for Edward Jenner's vaccination process? A) Exposure to a milder disease form may produce immunity. B) Disease is caused by viruses. C) Someone who recovers from a disease will not acquire that disease again. D) Pathogenic microorganisms infect all humans and animals in the same manner. E) A weakened microorganism will not cause disease.
a. exposure to a milder disease form may produce immunity
In the Gram stain, crystal violet remains in gram-positive cells after treatment with alcohol because crystal violet--iodine (CV--I) complexes are trapped __________. a. in thick layers of peptidoglycan b. in the outer membrane c. by endospores d. by flagella e. in mycolic acid
a. in thick layers of peptidoglycan
Which of the following is not characteristic of a protozoan? a. lacks organelles such as a mitochondrion. b. may be autotrophic or heterotrophic c. contains ribosomes in its cytoplasm d. may utilize a flagellum for locomotion
a. lacks organelles such as a mitochondrion
In which phase of the growth curve is the population-doubling time fastest? a. log phase b. lag phase c. logarithmic decline phase d. death phase e. stationary phase
a. log phase
Microbial control methods usually target any of the following microbial structuresEXCEPT which one? a. mitochondria b. microbial proteins c. plasma membrane d. permeability e. nucleic acids
a. mitochondria
Which of the following is not a functionally analogous pair of stains? a. nigrosin and malachite green b. crystal violet and carbolfuchsin c. safranin and methylene blue d. ethanol-acetone and acid-alcohol e. none of the above
a. nigrosin and malachite green
Bacteria that CANNOT grow in the presence of oxygen (O2) are called __________. a. obligate anaerobes b. facultative anaerobe c. aerotolerant anaerobe d. microaerophile
a. obligate anaerobes
The fate of E. coli O157:H7 in apple cider held at 8°C for 2 weeks, with and without preservatives, is shown below: - Cider only: 2.2 - Cider with potassium sorbate: 2.0 - Cider with sodium benzoate: 0.5 - Cider with potassium sorbate + sodium benzoate: 0 In the table, which preservative is most effective? a. potassium sorbate + sodium benzoate b. potassium sorbate c. no preservative d. sodium benzoate
a. potassium sorbate + sodium benzoate
Which of the following types of microorganisms and its description are NOT correctly matched? a. protozoa - small animals b. bacteria - prokaryotic c. fungi - eukaryotic d. helminths - multicellular animals
a. protozoa - small animals
You are performing a Gram stain on gram-negative bacteria and you stop after the addition of the mordant. What is the appearance of the bacteria at this point? a. purple b. red c. colorless d. brown
a. purple
Clostridium can be cultured in an anaerobic incubator or in the presence of atmospheric oxygen if thioglycolate is added to the nutrient broth. The addition of thioglycolate makes the medium __________. a. reduced b. selective c. differential d. enriched
a. reduced
Which of the following types of microscopy is used to study the structure of the slimy accumulation of bacteria on an IV catheter tip? a. Scanning acoustic b. Atomic force c. Scanning electron d. Phase-contrast e. Confocal
a. scanning acoustic
Pasteurization was first developed to kill __________ in wine. a. spoilage bacteria b. all bacteria c. disease-causing bacteria d. antibiotic-producing bacteria e. probiotic bacteria
a. spoilage bacteria
How would you recognize an antibiotic-producing soil bacterium on a plate crowded with other bacteria? The bacterial colony producing the antibiotic would be __________. a. surrounded by a clear area b. red or yellow c. star-shaped d. visible as massed called mycelia e. characterized by pseudopods
a. surrounded by a clear area
Pasteurized milk in an unopened container spoils in the refrigerator. A sample reveals the presence of microorganisms. The most likely explanation is __________. a. the microbes that survived pasteurization were able to grow at 4ºC b. the microbes are pathogens c. the pasteurization process was ineffective d. pasteurization-resistant mutants developed after pasteurization e. the milk was pasteurized too long
a. the microbes that survived pasteurization were able to grow at 4ºC
In the Gram-stain procedure, a clear oval in the center of a cell could indicate __________. a. the presence of an endospore b. a capsule c. an unstained nucleus d. lack of the central nucleoid e. the unstained bacterial chromosome
a. the presence of an endospore
Which of the following represents a chemical that is NOT an oxidizing agent and also would NOT be effective in killing the organism paired with it? a. triclosan; E. coli b. hypochlorite; cysts of protozoa c. hydrogen peroxide; Clostridium endospores d. chlorine; Mycobacterium tuberculosis e. ozone; Pseudomonas aeruginosa
a. triclosan; E. coli
If you were setting up an experiment to disprove spontaneous generation in a liquid medium, which of the following would be essential to the experiment? A) using a sterile liquid and eliminating exposure to microorganisms B) adding antibiotics to the liquid C) supplying the liquid with nutrients D) starting with a liquid that contains microorganisms E) adding carbon dioxide to the liquid
a. using a sterile liquid and eliminating exposure to microorganisms
All of the following factors contribute to the threat of emerging infectious diseases (EIDs) EXCEPT __________. a. vaccinations against various types of childhood diseases b. spread of known diseases to new geographic regions or populations by modern transportation c. increased human exposure to new, unusual infectious agents in areas that are undergoing ecological changes such as deforestation and construction d. evolutionary changes to existing organisms through genetic changes
a. vaccinations against various types of childhood diseases
The infectious agent that causes AIDS is a ______ A) virus. B) mold. C) bacterium. D) protozoan. E) yeast.
a. virus
Gluteraldehydes are among the most effective chemical control agents because they______.
are relatively safe, yet considered a sterilizing agent
The antibiotic amphothericin B disrupts plasma membranes by combining with sterols; it will affect all the following cells except: a) animal cells b) gram-negative bacterial cells c) fungal cells d) Mycoplasma cells e) plant cells
b) gram-negative bacterial cells
Which of the following pairs is mismatched? a) glycocalyx -- adherence b) pili -- reproduction c) cell wall -- toxin d) cell wall -- protection e) plasma membrane -- transport
b) pili -- reproduction
A broth medium has been inoculated, and microbial numbers will be counted periodically to generate a bacterial growth curve. At 2 hours after inoculation, the culture has progressed through lag phase and is now in log phase. At this point, the population size is 1 million cells. The generation time is 30 minutes. Assuming the continuation of log growth, how many cells would there be at 2 hours of growth in log phase? a. 8 million b. 16 million c. 4 million d. 32 million e. 2 million
b. 16 million
Chlamydia trachomatis elementary bodies measure approximately 0.25 micrometers in diameter. What is this measurement expressed in nanometers (nm)? a. 2500 nm b. 250 nm c. 25,000 nm d. 25 nm e. 2.5 nm
b. 250 nm
A scientist is using sterilized river water as a growth medium for her bacterial cultures. The nutrient availability is very low in this water, and no additional nutrients have been added. What type of membrane transport are the bacteria growing in this media most likely to be using to obtain nutrients? a. Pinocytosis b. Active transport c. Facilitated diffusion d. Simple diffusion e. Osmosis
b. Active transport
Penicillin was discovered by accident by a. Edward Jenner. b. Alexander Fleming. c. Joseph Lister. d. Robert Koch. e. Paul Ehrlich.
b. Alexander Fleming.
Which of the following names is incorrectly matched with their discovery? a. Lancefield—Classification of streptococci b. Beijerinck and Winogradsky—Gene therapy c. Watson and Crick—Structure and replication of DNA d. Avery, MacLeod, McCarthy—DNA was the hereditary material e. Lederberg and Tatum—Transfer of genetic material via conjugation
b. Beijerinck and Winogradsky—Gene therapy
A chemostat is continuous culture system that is designed to promote and prolong exponential growth and prevent bacteria from entering stationary phase. How might this work? a. Chemostats promote the formation of endospores, which enable the long-term survival of the bacteria. b. Chemostats provide a continued source of fresh nutrients and remove wastes and dead bacterial cells. c. Chemostats include growth-promoting agents that prolong microbial growth. d. Chemostats include detoxifying agents that inactivate growth-inhibiting toxins that develop during continued microbial growth.
b. Chemostats provide a continued source of fresh nutrients and remove wastes and dead bacterial cells.
Which of the following statements about biofilms is FALSE? a. Biofilms in your body protect mucous membranes from harmful microbes. b. Compared to free-living bacteria, biofilms are more sensitive to antibiotics. c. Biofilms in pipes can block the flow of water. d. Biofilms on rocks provide food for animal life. e. Biofilms on medical devices cause infections.
b. Compared to free-living bacteria, biofilms are more sensitive to antibiotics.
Which of the following is NOT characteristic of the glycocalyx found in bacteria? a. A structure that can be visualized by negative staining b. Creates a slimy, slippery coating that prevents bacteria form attaching to surfaces c. If firmly attached, contributes to bacterial virulence d. A viscous coating surrounding the cell made of polysaccharide, polypeptide, or both
b. Creates a slimy, slippery coating that prevents bacteria form attaching to surfaces
Which of the following is NOT a step in bacterial cell division? a. Splitting apart of two new daughter cells b. Disappearance of nuclear envelope c. Cell elongation d. Replication of the genetic material
b. Disappearance of nuclear envelope
Some microbes are very resistant to antimicrobial chemicals. Which of the following would be the easiest to kill? a. Pseudomonas aeruginosa b. E. coli c. Cysts of protozoa d. Clostridium endospores e. Mycobacterium tuberculosis
b. E. coli
Which of the following is the most effective for sterilization mattresses and plastic petri dishes? a. Chlorine b. Ethylene oxide c. Glutaraldehyde d. Autoclaving e. Nonionization radiation
b. Ethylene oxide
Before cells are stained, the specimen must be fixed. Fixing a specimen accomplishes all of the following EXCEPT which one? a. Fixation kills the cells that are being stained for observation. b. Fixation differentiates the various cells being observed. c. Fixation attaches cells to the slide so that they will not wash off during the staining process. d. Fixation preserves cellular structure in the natural state, with minimum distortion.
b. Fixation differentiates the various cells being observed.
Which of the following is true of microbes? a. 99% of all microbes are pathogenic. b. Gene expression in bacteria is very similar to gene expression in humans, which facilitates the use of bacteria in recombinant biotechnology and gene therapy. c. All bacterial enzymes are harmful to humans and the environment. d. Microbes create pollutants and toxins that harm the environment.
b. Gene expression in bacteria is very similar to gene expression in humans, which facilitates the use of bacteria in recombinant biotechnology and gene therapy.
Which of the following is most likely to be bactericidal? a. Membrane filtration b. Ionizing radiation c. Lyophilization (freeze-drying) d. Deep- freezing e. All of the above.
b. Ionizing radiation
A strain of Streptococcus pneumoniae is no longer able to synthesize its capsular polysaccharide. What is a likely outcome? a. It will produce more potent toxins which damage the host b. It will be readily phagocytized upon entering the host c. It will not be able to appropriately transport ions across its plasma membrane d. It will no longer be motile e. It will no longer be able to carry out fermentation
b. It will be readily phagocytized upon entering the host
Which of the following would be the most effective method in preserving bacterial cultures? a. Deep-freezing b. Lyophilization c. Refrigeration d. Autoclaving
b. Lyophilization
Which of the following is a likely outcome, based on the unique cell structure of members of the genus Mycoplasma? a. Mycoplasma species can release endotoxins when they lyse. b. Mycoplasma species have very flexible cells that can pass through bacteriologic filters. c. Mycoplasma species usually stain gram-positive. d. Mycoplasma species are susceptible to penicillin. e. Mycoplasma species are susceptible to disruption by lysozymes.
b. Mycoplasma species have very flexible cells that can pass through bacteriologic filters.
Which of these conditions is likely to interfere with the effectiveness of an antiseptic or disinfectant? a. Increased temperature b. Presence of biofilms c. Increased time of exposure d. Absence of endospores
b. Presence of biofilms
Which of the following is NOT a sign or symptom of a Clostridium difficile infection? a. Abdominal pain b. Respiratory distress c. Fever d. Bloody stools
b. Respiratory distress
Which of the following kinds of microscopy would be most appropriate for viewing the shape and arrangement of pili or fimbriae on the surface of a bacterial cell? a. Brightfield microscopy b. Scanning electron microscopy c. Darkfield microscopy d. Phase-contrast microscopy e. Transmission electron microscopy
b. Scanning electron microscopy
__________ has little value as an antiseptic but is important in the mechanical removal of microbes. a. Alcohol b. Soap c. Iodine d. Silver
b. Soap
Which of the following is not a characteristic of quaternary ammonium compounds? a. Bactericidal against gram positive bacteria b. Sporicidal c. Amebicidal d. Fungicidal e. Kills enveloped viruses.
b. Sporicidal
For which of the following can Koch's postulates be used to identify the organism causing the disease? a. Treponema pallidum, the causative agent of syphilis, which cannot be grown in the laboratory b. Streptococcus pyogenes, the organism that causes strep throat, which can be cultured on blood agar in the laboratory c. HIV (human immunodeficiency virus), the agent causing AIDS, a disease of the human immune system d. Allergies
b. Streptococcus pyogenes, the organism that causes strep throat, which can be cultured on blood agar in the laboratory
A classmate is trying to determine how a disinfectant might kill cells. You observed that when he spilled the disinfectant in your reduced litmus milk, the litmus turned blue again. You suggest to your classmate that. a. The disinfectant might inhibit cell wall synthesis. b. The disinfectant might oxidize molecules c. The disinfectant might inhibit protein synthesis. d. The disinfectant might denature proteins. e. He take his work away from yours.
b. The disinfectant might oxidize molecules
The nucleus of a eukaryotic cell differs from the nucleoid of a prokaryotic cell in all of the following ways EXCEPT which one? a. The eukaryotic nucleus contains nucleoli. There are no nucleoli in the prokaryotic nucleoid. b. The prokaryotic nucleoid contains DNA combined with histones. Histones are lacking in the eukaryotic nucleus. c. The eukaryotic nucleus is surrounded by a nuclear envelope. There is no envelope surrounding the prokaryotic nucleoid. d. The prokaryotic nucleoid usually contains a single circular chromosome, whereas the eukaryotic nucleus contains multiple linear chromosomes.
b. The prokaryotic nucleoid contains DNA combined with histones. Histones are lacking in the eukaryotic nucleus.
Which of these is NOT a characteristic of the autoclave? a. The use of high temperatures b. The requirement for long (hours) exposure times c. The use of high pressures d. The ability to sterilize solutions with endospores e. The use of moist heat
b. The requirement for long (hours) exposure times
A nurse is working in southeast Asia, where the incidence of Mycobacterium tuberculosis is very high. Why is it necessary to select a specific method of disinfection for this organism? a. The presence of an envelope makes this organism relatively resistant to disinfectants. b. The waxy, lipid-rich components of the cell wall make this organism relatively resistant to disinfectants. c. The presence of a capsule makes this organism more resistant to disinfectants. d. Bacterial endospores made by this organism are resistant to disinfectants.
b. The waxy, lipid-rich components of the cell wall make this organism relatively resistant to disinfectants.
__________ bacteria may survive pasteurization. a. Psychotroph b. Thermoduric c. Mesophiles d. Psychrophile
b. Thermoduric
In one hospital, Pseudomonas aeruginosa serotype 10 infected the biliary tract of 10 percent of 1300 patients who underwent gastrointestinal endoscopic procedures. After each use, endoscopes were washed with an automatic reprocessor that flushed detergent and glutaraldehyde through the endoscopes, followed by a tap water rinse. P. aeruginosa serotype 10 was not isolated from the detergent, glutaraldehyde, or tap water. What was the source of the infections? a. fecal contamination of the bile ducts b. a biofilm in the reprocessor c. bacterial cell walls in the water d. contaminated disinfectant e. None of the answers is correct.
b. a biofilm in the reprocessor
A population of bacterial cells has been placed in a very nutrient-poor environment with extremely low concentrations of sugars and amino acids. Which kind of membrane transport becomes crucial in this environment? a. facilitated diffusion b. active transport c. pinocytosis d. osmosis e. simple diffusion
b. active transport
An organism that has peroxidase and superoxide dismutase but lacks catalase is most likely an a. aerobe. b. aerotolerant anaerobe. c. obligate anaerobe.
b. aerotolerant anaerobe.
Which of the following organisms have eukaryotic cells that do NOT contain a cell wall? a. algae b. animals c. fungi d. plants
b. animals
Which of the following pairs is correctly matched? a. transmission electron microscope and ticks b. atomic force microscopes and DNA c. light microscope and viruses d. scanned-probe microscope and internal bacterial structures
b. atomic force microscopes and DNA
All of the following are examples of biotechnology EXCEPT __________. a. enzyme production by bacteria and fungi b. bacteria that cause disease or serve as normal microbiota c. antibiotic production by bacteria d. bread making with bacteria and fungi
b. bacteria that cause disease or serve as normal microbiota
Which of the following pairs is mismatched? a. nigrosin - negative stain b. basic dye - negative stain c. methylene blue - simple stain d. acidic dye - capsule stain e. crystal violet - simple stain
b. basic dye - negative stain
Arsenic is a relatively common hazardous waste generated by smelting processes and can contaminate soil and water surrounding smelting facilities. A bioprocess using naturally occurring bacteria to remove arsenic has been developed. This process is an example of __________. a. biotechnology b. bioremediation c. gene therapy d. fermentation e. nitrogen fixation
b. bioremediation
Normal microbiota a. almost always cause disease in the host. b. both indefinitely colonize the body and take up residence in sites such as the colon and mouth. c. take up residence in sites such as the colon and mouth. d. indefinitely colonize the body. e. are normally found in blood.
b. both indefinitely colonize the body and take up residence in sites such as the colon and mouth.
Many pathogenic (disease-producing) bacteria produce a(n) __________ that protects them from phagocytosis by host cells. a. flagellum b. capsule c. pilus d. endospore
b. capsule
Robert Hooke's observation of the individual units in thin layers of cork tissue led to the development of the __________ theory. a. biogenesis b. cell c. spontaneous generation d. germ
b. cell
The __________ is a fluid structure that allows membrane proteins to move freely. a. glycocalyx b. cell membrane c. ribosome d. cell wall
b. cell membrane
During the lag phase, __________. a. nutrients are depleted b. cells are engaged in intense enzymatic activity c. cells are decreasing in number d. changes in pH occur e. no cellular activity can be detected
b. cells are engaged in intense enzymatic activity
Which of the following is NOT a functionally analogous pair? a. mitochondria - prokaryotic plasma membrane b. cilia - pili c. nucleus -nucleoid region d. 9+2 flagella - bacterial flagella e. chloroplasts - thylakoids
b. cilia - pili
Gene therapy is currently used to treat all of the following diseases EXCEPT ______ A) LDL-receptor deficiency. B) colon cancer. C) Duchenne's muscular dystrophy. D) severe combined immunodeficiency disease (SCID). E) cystic fibrosis.
b. colon cancer
To look for bacteria that degrade petroleum, a culture medium containing crude oil, sodium nitrate, phosphate buffer, and magnesium sulfate is inoculated with soil. This medium is __________. a. reduced b. complex c. differential d. chemically defined
b. complex
The __________ of a compound light microscope focuses light from the light source on the specimen. a. objective b. condenser c. ocular lense d. stage
b. condenser
Through which structure would the light pass before it reaches the specimen affixed to the stage? a. ocular lens b. condenser c. objective d. illuminator
b. condenser
In which of the following situations would Koch's postulates be utilized? a. whenever the scientific method is used to investigate a microbiological problem b. determination of the cause of a new emerging disease by scientists studying disease transmission c. development of a new antibiotic in a pharmaceutical lab d. formulation of a vaccine against a new pathogen in a genetic engineering lab e. determination of the cause of cancer in a patient
b. determination of the cause of a new emerging disease by scientists studying disease transmission
Blood agar used to observe hemolysis or clearing around Streptococcus pyogenes colonies is an example of a(n) __________. a. reducing media b. differential medium c. selective media d. enrichment media e. isolation media
b. differential medium
Which of the following membrane transport mechanisms takes place in eukaryotic cells but NOT in prokaryotic cells? a. facilitated diffusion b. endocytosis c. osmosis d. active transport
b. endocytosis
Spirochetes and spirilla are both spiral-shaped bacteria. However, they differ in that spirochetes have __________ and spirilla do not. a. fimbriae b. endoflagella (axial filaments) c. peritrichous flagella d. N-acetylglucosamine
b. endoflagella (axial filaments)
Which of the following are NOT a major target for action of antimicrobials? a. proteins b. flagella c. enzymes d. nucleic acids e. cell membranes
b. flagella
Which of the following bacterial structures is necessary for chemotaxis? a. capsules b. flagella c. plasmids d. metachromatic granules
b. flagella
Which of the following types of microscopy can be used to specifically identify pathogens (such as Mycobacterium tuberculosis or rabies virus) in specimens? a. Brightfield b. Fluorescence c. Phase-contrast d. Darkfield e. Transmission electron
b. fluorescence
The endoplasmic reticulum that has ribosomes attached to its outer surface is referred to as __________. a. smooth ER b. rough ER c. wavy ER d. golgi
b. rough ER
Which of the following is an example of a metabolic activity that could be used to measure microbial growth? a. most probable number (MPN) b. glucose consumption c. direct microscopic count d. standard plate count e. turbidity
b. glucose consumption
__________ is important in medical microbiology because the results help physicians select appropriate antibiotics for treatment. a. simple staining b. gram staining c. the observation of morphology of bacteria d. the observation of the size of bacteria
b. gram staining
Carbolfuchsin can be used as a simple stain and a negative stain. As a simple stain, the pH is: a. 2 b. higher than the negative stain c. lower than the negative stain d. the same as the negative stain
b. higher than the negative stain
Which one of the following physical methods of microbial control is bactericidal? a. refrigeration b. incineration c. desiccation d. deep-freezing
b. incineration
A __________ solution is a medium in which the overall concentration of solutes equals that found inside the cell. Water enters and leaves the cell at the same rate. a. hypertonic b. isotonic c. hypotonic d. ionic
b. isotonic
The plasma membrane is considered a barrier to the environment because __________. a. no molecules may pass through it b. it controls the passage of molecules into the cell c. it is located outside of the cell wall d. only water and small molecules may penetrate the membrane e. it contains rigid cellulose and steroid molecules
b. it controls the passage of molecules into the cell
Place these structures of the compound light microscope in the order that light passes through them on the way to the observer's eyes: (1) condenser, (2) ocular lens, (3) light source, (4) specimen, (5) objective lens. a. ocular lens → condenser → specimen → light source → objective lens b. light source → condenser → specimen → objective lens → ocular lens c. light source → condenser → objective lens → specimen → ocular lens d. light source → specimen → condenser → objective lens → ocular lens
b. light source → condenser → specimen → objective lens → ocular lens
Which of the following statements is the best definition of biogenesis? a. Nonliving matter gives rise to living organisms b. Living cells can only arise from preexisting cells c. A vital force is necessary for life d. Air is necessary for living organisms e. Microorganisms can be generated from nonliving matter
b. living cells can only arise from preexisting cells
Which of the following is NOT an Emerging Infectious Disease? a. MERS (Middle East Respiratory Syndrome) b. Measles c. H1N1 influenza (swine flu) d. West Nile Encephalitis e. VRSA (vancomycin-resistant Staphylococcus aureus)
b. measles
A(n) __________ is equal to 0.000001 m. a. nanometer b. micrometer c. millimeter d. centimeter
b. micrometer
Which of the following is NOT a chemical requirement of all bacteria? a. carbon b. molecular oxygen c. nitrogen d. sulfur e. mineral elements
b. molecular oxygen
Chemotaxis refers to the ability of microorganisms to __________. a. survive under adverse conditions b. move toward or away from chemical stimuli c. attach to solid surfaces d. move in a wavelike motion e. escape phagocytosis
b. move toward or away from chemical stimuli
The ability of microbes to utilize N2 as a nitrogen source is called __________. a. nitrate fixation b. nitrogen fixation c. nitrite fixation d. nitrogen oxidation
b. nitrogen fixation
Hooke and van Leeuwenhoek helped to create the basis of the cell theory by __________. a. developing industrial products using microorganisms b. observing and documenting cells, and using microscopes to visualize the invisible structure of living things c. clarifying the connection between disease and microorganisms d. proving that living organisms originate spontaneously from nonliving materials
b. observing and documenting cells, and using microscopes to visualize the invisible structure of living things
Which of the following types of microscopy is most useful for viewing the internal structures of unstained specimens? a. brightfield b. phase-contrast c. confocal d. electron e. fluorescence
b. phase-contrast
This activity asks you to consider various methods of counting or estimating the size of bacterial populations and to select the method that will provide the most accurate data for plotting a bacterial growth curve. Which of the following methods would be most appropriate for gathering data to plot a bacterial growth curve throughout the four phases? a. direct microscopic count b. plate count c. indirect estimate based on turbidity d. electronic cell counter e. Any of these methods will provide reliable data for plotting a growth curve.
b. plate count
All of the following describe a major feature used to classify organisms into three domains (bacteria, archaea, and eukarya) EXCEPT _____________. a. presence or absence of peptidoglycan b. presence or absence of DNA c. nutritional and metabolic factors d. presence or absence of a nucleus
b. presence of absence of DNA
Immersion oil is used with the 100 × objective lens of the compound light microscope to __________. a. increase contrast by bending light. b. prevent the loss of resolution due to refraction c. separate the light into different wavelengths d. condense the light
b. prevent the loss of resolution due to refraction
__________ organisms are often responsible for food spoilage in refrigerated foods. a. Thermophile b. Psychrotroph c. Halophile d. Psychrophile
b. psychrotroph
Which of the following types of media would not be used to cultureaerobes? a. selective media b. reducing media c. enrichment media d. differential media e. complex media
b. reducing media
Gram-negative cells contain a periplasmic space that is __________. a. the site of protein synthesis b. rich in degradative enzymes c. abundant in teichoic acid d. a site of endocytosis e. filled with lysozyme
b. rich in degradative enzymes
All of the following can be used to preserve bacterial cultures EXCEPT __________. a. refrigeration b. storing cultures at room temperature (25°C) c. lyophilization (freeze-drying) d. freezing quickly and storing at -70°C
b. storing cultures at room temperature (25°C)
Vaccinations are available for all of the following diseases EXCEPT ______ A) measles. B) strep throat. C) mumps. D) rubella. E) hepatitis B.
b. strep throat
All of the following are true of the plate count method EXCEPT that it __________. a. is dependable b. takes less than 12 hours to complete c. measures number of viable cells d. involves cell plating and growth e. is the most commonly used method for assay of bacterial cell number
b. takes less than 12 hours to complete
You are viewing a sputum smear that has been stained with an acid-fast stain. On this smear you see 5-micrometer-long red cells. You can conclude that __________. a. human cells are acid-fast b. there are acid-fast bacteria in the specimen c. normal microbiota are acid-fast d. normal microbiota are gram-negative e. there are no acid-fast bacteria in the specimen
b. there are acid-fast bacteria in the specimen
You inoculate two tubes of liquid culture medium with 100 bacterial cells and incubate one tube at 37°C and the other at 55°C. After 48 hours, there are 20,000 bacteria per milliliter in the 37°C tube and 1,568,000 bacteria per milliliter in the 55°C tube. You conclude that this species is a __________. a. mesophile b. thermophile c. hyperthermophile d. psychrophile
b. thermophile
A student is observing an object that displays the internal detail on a virus at great magnification. Which type of microscope is used for this image? a. scanning electron microscope b. transmission electron microscope c. light microscope d. scanning acoustic microscope
b. transmission electron microscope
Jenner's work with vaccinations depended on which of the following? a. Exposing patients to the exact pathogen he was trying to protect them from b. Trusting that the body produced agents that effectively overcame a disease-causing microbe c. Selecting a microbe that could easily evade the immune system d. Selecting a pathogen that was a bacterium
b. trusting that the body produced agents that effectively overcame a disease-causing microbe
Assume that you are viewing a Gram-stained field of red cocci and blue bacilli through the microscope. You can safely conclude that you have: a. made a mistake in staining b. two different species c. old bacterial cells d. young bacterial cells e. none of the above
b. two different species
Bacterial cells have an overall negative charge on their surface. If a bacterial smear is stained by a pink, acidic, water-soluble stain and then washed with water, which of the following describes the result that will be observed when viewing the stained slide under a microscope? a. pink cells b. Unstained cells with no background c. Unstained cells in a pink background d. Pink cells in a pink background e. Purple cells
b. unstained cells with no background
In a negative staining procedure, the bacterial cells would appear __________ when viewed under a microscope. a. brightly colored in a contrasting background b. unstained in a colored background c. stained in an unstained background d. attracted to the dye used in the staining procedure e. the same color as the background and thus not easily observed
b. unstained in a colored background
Which of the following best describes gene therapy? a. use of microbes for bioremediation b. use of a harmless virus to insert a gene in a host cell c. use of microbes to control pests d. use of microbes to recycle nitrogen from the air into the soil
b. use of a harmless virus to insert a gene in a host cell
Pasteurization was first used by Pasteur to control spoilage of __________. a. milk b. wine c. yogurt d. cheese e. canned foods
b. wine
The figure shows a typical bacterial growth curve with the y-axis indicating the log of the number of bacteria and the x-axis indicating time in culture. In the figure, which section (or sections) shows a growth phase where the number of cells dying equals the number of cells dividing? a b c d a and c
c
A microorganism measures 5 μm in length. Its length in mm would be a. 500 mm. b. 0.05 mm. c. 0.005 mm. d. 0.5 mm. e. 50 mm.
c. 0.005 mm.
If a single bacterium replicated every 30 minutes, how many bacteria would be present in 2 hours? a. 4 b. 8 c. 16 d. 32 e. 64
c. 16
The most resistant of the bacterial endospores can withstand boiling for up to a. 10 min. b. 5 hours. c. 20 hours. d. 1 hour. e. 30 min.
c. 20 hours.
When using a 10× ocular lens and a 40× objective, the total magnification achieved is __________. a. 10 b. 40 c. 400 d. 50
c. 400
Assume that you inoculated potato salad with 10 bacterial cells and stored it at room temperature. After 3 hours, there are 640 cells. How many generations did the cells go through? a. 1 generation b. 3 generations c. 6 generations d. 12 generations
c. 6 generations
A nurse is degerming a patient's arm before giving a vaccination. Which of these concentrations of alcohol is most effective? a. 50% b. 100% c. 70% d. 25%
c. 70%
Alcohol is most effective when used as a __________ solution. a. 95% b. 100% c. 70% d. 25% e. 60%
c. 70%
Which of the following is true of an antimicrobial substance with a microbial death rate of 90% after 1 minute? a. All of the microbes would be killed instantly upon application of the agent. b. After the first 2 minutes of application of the agent, 10% of the original microbial count survives. c. After the first minute of application of the agent, 10% of the original microbes are still left on the surface. d. After 1 minute of application of the agent, 75% of the microbes would be killed.
c. After the first minute of application of the agent, 10% of the original microbes are still left on the surface.
Which of the following regarding antimicrobial control agents is FALSE? a. Contaminating organic debris such as blood or sputum decrease effectiveness. b. Some agents affect microbial cell membranes by dissolving lipids. c. Alcohols effectively inactivate nonenveloped viruses by attacking lipids. d. Some agents kill by denaturing microbial cell proteins. e. Silver-impregnated dressings are used for treating antibiotic-resistant bacteria.
c. Alcohols effectively inactivate nonenveloped viruses by attacking lipids.
Which of the following are correctly matched? a. Pasteur—antisepsis b. Erhlich—vaccinations c. Fleming—antimicrobials d. Koch—microscopy
c. Fleming—antimicrobials
Operating rooms may receive ventilation from air that has passed through __________ filters to remove microorganisms. a. air b. UV c. HEPA d. dust
c. HEPA
__________ acts to decrease refraction of light rays and thus increase resolution. a. The condenser b. The glass slide c. Immersion oil d. The specimen
c. Immersion oil
Which of the following is NOT true of the gram-negative outer membrane? a. It is a part of the gram-negative cell wall. b. It contains lipopolysaccharide. c. It contains enzymes for energy synthesis. d. It has polysaccharide antigens that are useful in bacterial identification. e. It contains lipids also known as endotoxins.
c. It contains enzymes for energy synthesis.
Which of the following is NOT a type of a compound microscope? a. brightfield microscope b. fluorescent microscope c. electron microscope d. darkfield microscope
c. electron microscope
A student is observing a Gram stain with the 100 × (oil immersion) lens. The image appears cloudy and dark. Which of the following actions will NOT increase the clarity of the image? a. Increasing the light using the diaphragm b. Using lens paper to clean any dirt or old oil off the lenses c. Lowering the stage to increase the distance between the object and the objective lens d. Adjusting the condenser to better focus light through the specimen
c. Lowering the stage to increase the distance between the object and the objective lens
What is the typical mechanism of action for chemical food preservatives? a. Disruption of plasma membranes b. Oxidation c. Metabolic inhibition d. Surface-active agents for removal of microbes
c. Metabolic inhibition
Which type of radiation is LEAST effective in killing microbes? a. High-energy electron beams b. Ultraviolet rays c. Microwaves d. X rays e. Gamma rays
c. Microwaves
Which of the following statements about culture media is FALSE? a. Complex media are formulated from nutrient-rich whole food sources whose exact ingredients may not be known. b. Reducing media are complex media containing chemicals, such as thioglycolate, that combine with oxygen, creating an anaerobic environment. c. Nutrient agar contains ingredients that combine with oxygen and remove it. d. A chemically defined medium is specifically formulated, and each ingredient is known.
c. Nutrient agar contains ingredients that combine with oxygen and remove it.
Which of the following fields of study and its example are NOT correctly matched? a. Mycology—study of athlete's foot b. Immunology—study of vaccines c. Parasitology—study of HIV d. Bacteriology—study of E. coli O157:H7
c. Parasitology—study of HIV
Which of the following is true about antibiotics? a. Antibiotics are strong chemicals that resist microbial enzymes, retaining antimicrobial activity at all times. b. Antibiotics are chemotherapeutic agents that are always produced in the laboratory. c. Previously treatable microbes have become resistant to some antibiotics. d. Antibiotics kill a wide range of organisms, including viruses.
c. Previously treatable microbes have become resistant to some antibiotics.
Which of these microbes is the most difficult to destroy using either chemical or physical methods? a. MRSA (methicillin-resistant Staphylococcus aureus) b. Bacterial endospores c. Prions d. HIV
c. Prions
__________ ammonium compounds are less effective against gram-negative bacteria and more effective against gram-positive bacteria. a. Secondary b. Tertiary c. Quaternary d. Primary
c. Quaternary
Martian soil is inoculated into a glucose-containing medium. The radioactive form of carbon, 14C, is used in the glucose. After incubation for five days, which of the following would provide evidence suggesting that there is life on Mars? a. No radioactivity b. Radioactive soil c. Radioactive carbon dioxide d. Radioactive glucose
c. Radioactive carbon dioxide
What do all of these bacteria have in common? - Bacteria in the rumen of cattle and sheep - Bacteria in a sewage treatment plant - Bacteria growing in the middle ear in chronic otitis media - Bacteria growing on the teeth in dental plaque a. The bacteria are all gram-positive. b. The bacteria are all thermophilic. c. The bacteria are most likely growing in biofilms. d. The bacteria are all fermenters. e. The bacteria are all obligate aerobes.
c. The bacteria are most likely growing in biofilms.
When bacteria are inoculated into a new sterile nutrient broth, their numbers don't begin to increase immediately. Instead, there is a lag phase that may last for an hour or even several days. Why don't bacterial numbers increase immediately? a. The bacteria have to establish a biofilm before their numbers can increase. b. There are not enough nutrients for the bacteria to grow, and growth is delayed until there are some dead cells to cannibalize. c. The bacteria must adjust to the nutrient content in the new medium, synthesizing necessary amino acids, growth factors, and enzymes. d. The medium contains inhibitors that prohibit rapid growth of the bacteria, and these must be inactivated before bacterial numbers will increase.
c. The bacteria must adjust to the nutrient content in the new medium, synthesizing necessary amino acids, growth factors, and enzymes.
A student completes a Gram stain on a bacterial smear that has a mix of gram-negative and gram-positive organisms. The student stops the procedure without adding safranin. What would be the outcome of the Gram stain? a. All organisms would appear pink (gram-negative). b. The Gram stain would show pink (gram-negative) and purple (gram-positive) bacteria. c. The gram-positive organisms would appear purple, and the gram-negative organisms would be colorless. d. All organisms would appear colorless.
c. The gram-positive organisms would appear purple, and the gram-negative organisms would be colorless.
Which of the following are FALSE concerning microbes? a. Microbes produce vitamins in the intestines. b. Microbes generate oxygen through photosynthesis. c. The primary role of microbes on the planet involves causing disease in animals and humans. d. Microbes play a role in breaking down waste and decomposing dead organisms.
c. The primary role of microbes on the planet involves causing disease in animals and humans.
Which of the following statements is INCORRECT regarding prokaryotic cells? a. They typically have a circular chromosome. b. They lack membrane-enclosed organelles. c. They lack a plasma membrane. d. They reproduce by binary fission. e. Their DNA is not enclosed within a membrane.
c. They lack a plasma membrane.
In the Gram stain, what is the purpose of the counterstain? a. To decolorize gram-positive cells b. To make gram-positive cells visible c. To make gram-negative cells visible d. To decolorize gram-negative cells
c. To make gram-negative cells visible
Which of these chemicals inhibits an enzyme required for synthesis of membrane lipids? a. Hydrogen peroxide b. Chlorine c. Triclosan d. Ozone
c. Triclosan
Which one of the following is an example of bioremediation? a. Use of cowpox virus to vaccinate against smallpox b. Use of Bacillus thuringiensis to kill crop-eating insects c. Use of Pseudomonas to remove uranium from soil at weapons depots d. Use of Saccharomy cescerevisiae to make wine
c. Use of Pseudomonas to remove uranium from soil at weapons depots
For control of microbial growth on a surface, which of these conditions is LEAST likely to interfere with the effectiveness of an antiseptic or disinfectant? a. High numbers of microbes b. Presence of biofilms c. Warm environmental conditions d. Presence of organic matter
c. Warm environmental conditions
Which type of solution would cause a bacterium with a weak or damaged cell wall to burst as water moves into the cell? a. an isotonic solution b. a hypertonic solution c. a hypotonic solution d. either a hypotonic or an isotonic solution
c. a hypotonic solution
Campylobacter bacteria are grown with a CampyPak that produces 5% carbon dioxide and 15% oxygen. This bacterium is __________. a. an anaerobe b. a capnophile c. a microaerophile d. an aerotolerant anaerobe
c. a microaerophile
When stained, bacteria in the genus Mycobacterium are __________. a. gram positive b. gram negative c. acid fast d. all of the listed responses are correct e. none of the listed responses are correct
c. acid fast
29) Robert Koch identified the cause of ______ A) diphtheria. B) tuberculosis. C) anthrax. D) smallpox. E) AIDS.
c. anthrax
Bacillus anthraciscauses the deadly disease anthrax. Organisms of the genus Bacillus may form endospores. This bacterium would be suitable for biological warfare because endospores __________. a. are multilayered structures b. are difficult to stain c. are resistant to high temperatures, UV light, and desiccation d. are centrally located within the bacterial cells e. contain a high concentration of toxic enzymes
c. are resistant to high temperatures, UV light, and desiccation
A new microorganism has been isolated from hot springs in Yellowstone National Park. It consists of single cells, which appear to lack a nucleus. Chemical analysis shows the presence of both DNA and RNA in the cytoplasm and peptidoglycan in the cell wall. In which of the following groups will this organism be classified? a. archaea b. fungi c. bacteria d. plants e. protists
c. bacteria
Which of the following is characteristic of bacteria? a. bacteria live in extreme environments including pH, temperature, and pressure extremes b. bacteria have DNA and RNA, but not both c. bacteria lack a membrane-bound nucleus d. bacteria reproduce by a cell-division process known as mitosis e. bacteria have cellulose or chitin in their cell wall
c. bacteria lack a membrane-bound nucleus
Bacteria reproduce by __________. a. lysogeny b. mitosis c. binary fission d. meiosis
c. binary fission
Normal microbiota are typically found in and on all the following body locations EXCEPT the ______ A) mouth. B) upper respiratory system. C) blood. D) colon. E) skin.
c. blood
In the figure, which line best depicts a psychrotroph incubated at 0°C? a. a b. b c. c
c. c
Only a small percentage of microbes a. maintain balance between chemicals in the environment b. are pests that cause devastating crop diseases c. cause disease d. produce important products for living organisms, such as oxygen and vitamins
c. cause disease
Evaluate the following chemical agents in regard to the effective use against endospores and mycobacteria. In a clinical situation where it is essential to control microbial growth that includes both mycobacteria and endospores, which chemical agent would be the most effective to guarantee the broadest disinfection? a. alcohols b. phenolics c. chlorines d. iodine
c. chlorines
Which of the following is NOT a structure of prokaryotic cells? a. flagellum b. capsule c. chloroplast d. chromosome e. ribosome
c. chloroplast
In the capsule stain using India ink, capsules are distinguished as __________ surrounding cells. a. pink circles b. green shadows c. clear halos d. purple rims e. blue extensions
c. clear halos
An exposure to _________ protects against infection with smallpox. a. penicillin b. chemotherapy c. cowpox d. bacteria e. normal microbiota
c. cowpox
What is the correct order for the Gram stain process? a. crystal violet → safranin → decolorizer → iodine b. iodine → crystal violet → decolorizer → safranin c. crystal violet → iodine → decolorizer → safranin d. malachite green → crystal violet → decolorizer → safranin
c. crystal violet → iodine → decolorizer → safranin
It has been said hat bacteria are essential for the existence of life on Earth. Which of the following is the essential function performed by bacteria? a. control insect populations b. directly provide food for humans c. decompose organic material and recycle elements d. cause disease e. produce hormones such as insulin
c. decompose organic material and recycle elements
Sterilization is the __________. a. elimination of all gram-negative bacteria b. elimination of vegetative bacterial cells and fungal spores c. destruction of all microbial life d. destruction of all forms of microbial life except endospores e. reduction of microbial growth
c. destruction of all microbial life
Lister knew that carbolic acid (phenol) kills bacteria. He used it as the first __________. a. antibiotic b. vaccine c. disinfectant d. gene therapy
c. disinfectant
Increased human exposure to new and unusual infectious agents in areas that are undergoing ecologic changes accounts for the __________. a. debate over the use of vaccines b. increased incidence of smallpox c. emergence of new infectious diseases d. lack of natural resistance to infectious disease e. development of antibiotic-resistant bacteria
c. emergence of new infectious diseases
Assume you stain Bacillus by applying malachite green with heat and then counterstain with safranin. Through the microscope, the green structures are: a. cell walls b. capsules c. endospores d. flagella e. impossible to identify
c. endospores
__________ is used to sterilize medical equipment that might be damaged by exposure to the heat of autoclaving. a. bleach b. iodine c. ethylene oxide gas d. alcohol
c. ethylene oxide gas
Which of the following processes uses membrane proteins that act as channels or carriers allowing ions or large molecules to move across the plasma membrane without using energy? a. active transport b. osmosis c. facilitated diffusion d. simple diffusion
c. facilitated diffusion
An organism that grows both in the presence and the absence of oxygen and uses oxygen when it is available is called a(n) __________. a. aerobe b. microaerophile c. facultative anaerobe d. anaerobe e. aerotolerant anaerobe
c. facultative anaerobe
You are testing the number of coliforms in a drinking water source. Which of the following test methods would be best to use? a. turbidity b. dry weight c. filtration d. direct microscopic count
c. filtration
__________ are too small to be seen with the light microscope without adding a mordant and carbolfuchsin. a. ribosomes b. nuclei c. flagella d. mitochondria
c. flagella
Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper? a. microwaves b. autoclave c. gamma radiation d. sunlight e. ultraviolet radiation
c. gamma radiation
A Gram stain of a wound reveals purple, spherical bacteria that divide and remain attached in grapelike clusters. These are referred to as __________. a. gram-positive streptococci b. gram-positive tetrads c. gram-positive staphylococci d. gram-negative spirochetes
c. gram-positive staphylococci
Surface-active agents act by decreasing surface tension so that microbes can more easily be removed. All of the following agents use this mechanism of action EXCEPT __________. a. acid-anionic sanitizers b. quaternary ammonium compounds (quats) c. halogens d. soaps and detergents
c. halogens
Which of the following is not a characteristic of bacteria? a. are prokaryotic b. have peptidoglycan cell walls c. have the same shape d. grow by binary fission e. have the ability to move
c. have the same shape
Polyphosphate (volutin), carboxysomes, and magnetosomes are examples of __________. a. chloroplasts b. capsules c. inclusion bodies d. fimbriae e. mesosomes
c. inclusion bodies
Within the cytoplasm of bacterial cells are reserve deposits where certain nutrients accumulate. These are called __________. a. vacuoles b. ribosomes c. inclusions d. lysosomes
c. inclusions
Microorganisms are essential to our life. Each of the following is an example of a beneficial function of microorganisms EXCEPT a. agriculture b. bioremediation c. increased number of illnesses d. gene therapy e. alternative fuel production
c. increased number of illnesses
The following steps occur during binary fission. What is the third step? a. cell elongation b. DNA replication c. inward growth of membrane d. cross-wall formation
c. inward growth of membrane
Which of the following is not a characteristic of biofilms? a. antibiotic resistance b. hydrogel c. iron deficiency d. quorum sensing
c. iron deficiency
The term describing bacteria with flagella that are arranged as a tuft coming from one pole is __________. a. amphytrichous b. peritrichous c. lophotrichous d. monotrichous
c. lophotrichous
Ehrlich searched for a/an __________ that would destroy a pathogen without harming the infected host. a. vital force b. vaccine c. magic bullet d. herbal remedy e. pathogen
c. magic bullet
Microbes have very narrow optimum temperature ranges. Which of the following classifications of microbes are most likely to cause human disease, based on temperature requirements? a. psychrophiles b. thermophiles c. mesophiles d. hyperthermophiles
c. mesophiles
Which of the following is the most convenient and appropriate unit for expressing the size of an average bacterial cell? a. millimeter b. centimeter c. micrometer d. nanometer
c. micrometer
Which of the following are NOT typically destroyed byantibacterial agents? a. nucleic acids b. plasma membranes c. nuclei d. proteins
c. nuclei
The term used to describe a disease-causing microorganism is: a. microbe b. infection c. pathogen d. virus e. bacterium
c. pathogen
Disinfection of water is achieved by all of the following EXCEPT a. chlorine. b. ozone. c. peracetic acid. d. copper sulfate. e. UV radiation.
c. peracetic acid.
Fimbriae and pili differ in that a. there are only one or two pili per cell. b. pili are used to transfer DNA. c. pili are used for transfer of DNA and motility. d. pili are used for motility. e. pili are used for attachment to surfaces.
c. pili are used for transfer of DNA and motility.
In the Gram stain, crystal violet is the __________. a. counterstain b. fixative c. primary stain d. mordant e. decolorizing agent
c. primary stain
Bacteria require nitrogen for the synthesis of __________. a. lipids b. carbohydrates c. proteins d. fatty acids e. sugars
c. proteins
__________ is the quality of the microscope that allows one to distinguish between two points that are very close together. a. refractive index b. magnification c. resolution d. oil immersion
c. resolution
Martin Lewis agar is an enriched media (containing heated blood) designed for the growth of Neisseria gonorrhea. Antibiotics are added to suppress the growth of normal microbiota that may be found in patient specimens, yet permit the growth of Neisseria gonorrhea. This medium would best be described as __________. a. differential media b. broad spectrum media c. selective media d. nutrient agar e. reduced media
c. selective media
An antiseptic is used to remove microbes from __________. a. toilet surfaces b. food preparation areas c. skin, before an injection d. foods, before canning them e. restaurant glassware
c. skin, before an injection
Spallanzani's conclusion about spontaneous generation was challenged because Lavoisier had just shown that oxygen was the vital component of air. Which of the following statements is true? a. All life requires air b. Only disease-causing organisms require air c. Some microbes do not require air d. Pasteur kept air out of his biogenesis experiment e. Lavoisier was mistaken
c. some microbes do not require air
Which of the following pairs is matched correctly? a. L form—a wall-less bacterium created by the action of lysozyme; the plasma membrane remains intact, and the cell carries on metabolism b. Mycoplasma spp.—bacteria that spontaneously, or in response to penicillin or lysozyme, partially lose their cell walls and swell into irregularly shaped bacteria that divide and metabolize and may regain their cell wall c. spheroplast—gram-negative bacteria that are exposed to lysozyme but retain some of the outer membrane d. protoplast—a genus of bacteria that typically do not have cell walls
c. spheroplast—gram-negative bacteria that are exposed to lysozyme but retain some of the outer membrane
Spherical bacteria that divide and remain attached in chainlike patterns are called __________. a. staphylococci b. tetrads c. streptococci d. spirochetes
c. streptococci
All of the following are found in the cell walls of gram-negative bacteria EXCEPT __________. a. lipid A b. porins c. teichoic acid d. N-acetylglucosamine e. tetrapeptide chains
c. teichoic acid
Recombinant DNA is? a. DNA in bacteria b. the study of how genes work c. the DNA resulting when genes of two different organisms are mixed d. the use of bacteria in the production of foods e. the production of proteins by genes
c. the DNA resulting when genes of two different organisms are mixed
Assume you inoculated 100 facultatively anaerobic cells onto nutrient agar and incubated the plate aerobically. You then inoculated the second plate anaerobically. After incubation for 24 hours, you should have.... a. more colonies on the aerobic plate b. more colonies on the anaerobic plate c. the same number of colonies on both plates
c. the same number of colonies on both plates
Molecular biology is the study of ______ A) DNA synthesis. B) protein synthesis. C) the structure and function of macromolecules essential to life. D) RNA replication. E) enzyme function.
c. the structure and function of macromolecules essential to life
Why are viruses not classified as prokaryotes or eukaryotes? a. they lack a cell wall b. they lack peptidoglycan c. they need a host to survive, thus are not considered alive d. they are so small, an electron microscope is needed to observe them
c. they need a host to survive, thus are not considered alive
The motility of bacteria with flagella occurs through a series of "runs" and __________. a. phototaxis b. chemotaxis c. tumbles d. turns
c. tumbles
Which of the following pairs is mismatched? a. plasma sterilization - free radicals b. ozone - takes electrons from substances c. ultraviolet radiation - desiccation d. supercritical fluids - CO2 e. ionizing radiation - hydroxyl radicals
c. ultraviolet radiation - desiccation
Acid-fast Mycobacteria differ from non-acid-fast bacteria by the presence of __________. a. capsules b. endospores c. waxy material in their cell walls d. flagella e. peptidoglycan
c. waxy material in their cell walls
Which of the following statements best describes what happens to a cell exposed to polymyxins that destroy phospholipids? a) in an isotonic solution, nothing will happen b) in a hypotonic solution, the cell will lyse c) water will move into the cell d) intracellular contents will leak from the cell e) any of the above might happen
d) intracellular contents will leak from the cell
Which statement best describes what happens when a gram-positive bacterium is placed in distilled water and penicillin? a) No change will result; the solution is isotonic b) Water will move into the cell c) Water will move out of the cell d) the cell will undergo osmotic lysis e) Sucrose will move into the cell from an area of higher concentration to one of lower concentration
d) the cell will undergo osmotic lysis
A paramecium is approximately 150 micrometers in length. What is this measurement expressed in millimeters (mm)? a. 1.5 mm b. 0.015 mm c. 1500 mm d. 0.15 mm e. 15 mm
d. 0.15 mm
Assume you stain Clostridium by applying a basic stain, carbolfuchsin, with heat, decolorizing with acid-alcohol, and counterstaining with an acid stain, nigrosin. Through the microscope, the endospores are (1)____, and the cells are stained (2)____. a. 1 - red; 2 - black b. 1 - black; 2 - colorless c. 1 - colorless; 2 - black d. 1 - red; 2 - colorless e. 1 - black; 2 - red
d. 1 - red; 2 - colorless
If 52 bacterial colonies grow on a nutrient agar plate inoculated with 1 ml of a 1:1000 dilution of hamburger, how many bacteria are in the original hamburger sample? a. 52 bacteria per gram b. 520 bacteria per gram c. 5200 bacteria per gram d. 52,000 bacteria per gram
d. 52,000 bacteria per gram
Decimal reduction time is the time in minutes in which __________ of the population at a given temperature will be killed. a. 10% b. 75% c. 100% d. 90%
d. 90%
Which of the following inanimate objects could ordinarily be treated with a low-level disinfectant? a. An endoscope used to examine the colon b. An endospore-contaminated rectal thermometer c. A surgical scalpel d. A hospital scale
d. A hospital scale
What does refraction mean? a. The ability of a microscope to stay in focus when the objective lenses are moved from low to high magnification b. The ability of a microscope to distinguish fine details and differentiate between two very close objects c. The total magnification of the visual image seen d. A measure of the light-bending ability of a medium
d. A measure of the light-bending ability of a medium
The acid-fast stain differs from the Gram stain procedure in the decolorizing agent used. What is the reagent used in an acid-fast stain, and why is it necessary? a. Acetone-alcohol is used as the decolorizer in order to enhance the primary stain. b. Acetone is used as the decolorizer to penetrate the endospore. c. Alcohol is used as the decolorizer in order to penetrate the bacterial capsule. d. Acid-alcohol is used to remove the primary stain from bacteria that do not have waxy cell walls.
d. Acid-alcohol is used to remove the primary stain from bacteria that do not have waxy cell walls.
Which of the following factors contributes to the frequency of healthcare-associated infections (HAIs)? a. Transmission from healthcare professionals to patients. b. The presence of patients with weakened immune systems. c. The presence of a wide range of pathogens in the healthcare environment. d. All of the above
d. All of the above
Which of the following statements about ribosomes is FALSE? a. Eukaryotic ribosomes are larger (80S) than prokaryotic ribosomes (70S). b. Cells with a high rate of protein synthesis have large numbers of ribosomes. c. Antibiotics that interfere with protein synthesis harm prokaryotic ribosomes, but not eukaryotic ribosomes. d. Antibiotics that interfere with protein synthesis harm both prokaryotic and eukaryotic ribosomes.
d. Antibiotics that interfere with protein synthesis harm both prokaryotic and eukaryotic ribosomes.
Which of the following cannot be used to sterilize a heat- labile solution stored in a plastic container? a. Gamma radiation b. Ethylene oxide c. Supercritical fluids d. Autoclaving e. Short- wave length radiation.
d. Autoclaving
Which of the following treatments achieves sterilization? a. Freezing b. Pasteurization c. Bringing water to a boil d. Autoclaving
d. Autoclaving
Which biosafety level features open laboratory bench tops, gloves, lab coat, and face and eye protection? a. BSL-1 b. BSL-3 c. BSL-4 d. BSL-2
d. BSL-2
Which term refers to an agent that inhibits bacterial growth? a. Fungicidal b. Germicidal c. Homeostatic d. Bacteriostatic e. Bactericidal
d. Bacteriostatic
Which one of these halogen compounds would be considered an antiseptic? a. Chlorine gas b. Hypochlorous acid c. Calcium hypochlorite d. Chlorine dioxide
d. Chlorine dioxide
Which of the following are NOT major targets for action of antimicrobials? a. Proteins b. Enzymes c. Nucleic acids d. Flagella e. Cell membranes
d. Flagella
Which one of these products is most useful for disinfecting medical instruments? a. Iodine b. Soap and detergents c. Alcohols d. Glutaraldehyde
d. Glutaraldehyde
Which one of the following pairs is correctly matched? a. lysosomes—secretion b. mitochondrion—cell division c. centrioles—cellular respiration d. Golgi complex—membrane formation and secretion of proteins
d. Golgi complex—membrane formation and secretion of proteins
Penicillin specifically interferes with peptidoglycan synthesis. Which of the following cells is most likely to be damaged by penicillin? a. Cells of archaea b. Yeast cells c. Human cells d. Gram-positive bacterial cells
d. Gram-positive bacterial cells
You are observing a Gram stain of rod-shaped microorganisms that are linked in a chain and stain purple. How would you describe these bacteria using the correct terminology for the cell shape and arrangement? a. Gram-positive tetrads b. Gram-negative staphylococci c. Gram-positive coccobacilli d. Gram-positive streptobacilli
d. Gram-positive streptobacilli
Which of these disinfectants does not act by disrupting the plasma membrane? a. Phenolics b. Phenol c. Quats d. Halogens e. Biguanides
d. Halogens
Which of the following terms are mismatched? a. Extreme thermophiles; 100°C b. Extreme halophiles; 30% salt c. Psychrophiles; 0°C d. Hyperthermophiles; 0°C e. Acidophiles; low pH
d. Hyperthermophiles; 0°C
Which of the following statements is true? a. Quats are sporicidal, while hypochlorite-based disinfectants are not. b. Quats are halogen-based disinfectants, while hypochlorite-based disinfectants are cationic detergents. c. Quats are considered high-level disinfectants, while hypochlorite-based disinfectants are not. d. Hypochlorite-based disinfectants are effective against a wider range of pathogens than quats.
d. Hypochlorite-based disinfectants are effective against a wider range of pathogens than quats.
Which statement regarding the structure or function of ribosomes is correct? a. The ribosomes in the prokaryote are slightly larger than those found in the eukaryotic endoplasmic reticulum. b. Ribosomes are found both free-floating and attached to the rough endoplasmic reticulum in eukaryotes and in prokaryotes. c. Ribosomes are the sites of lipid biosynthesis in both prokaryotes and eukaryotes. d. In eukaryotes, the ribosomes found in chloroplasts and mitochondria are 70S ribosomes, which are similar in size to prokaryotic ribosomes.
d. In eukaryotes, the ribosomes found in chloroplasts and mitochondria are 70S ribosomes, which are similar in size to prokaryotic ribosomes.
What is the role of iodine in the Gram stain process? a. Iodine is a basic purple dye, which acts as the primary stain in the Gram stain technique. b. Iodine is the decolorizer removing the primary stain after the first step in the Gram stain technique. c. Iodine is a pink dye that acts as the primary stain in the Gram stain technique. d. Iodine is a mordant in the Gram stain technique, which functions to intensify the primary stain.
d. Iodine is a mordant in the Gram stain technique, which functions to intensify the primary stain.
Which of the following statements is correct about passive diffusion? a. It is a process in which molecules move from a region of lower concentration to one of higher concentration (or up a concentration gradient). b. It requires an expenditure of energy by the cell. c. It may require a transport protein. d. It involves movement of molecules down a concentration gradient and may require a transport protein. e. It is a process in which molecules move from a region of higher concentration to a region of lower concentration (or down a concentration gradient).
d. It involves movement of molecules down a concentration gradient and may require a transport protein.
A strain of Neisseria gonorrhoeae has been genetically altered and can no longer produce fimbriae. What is a likely outcome? a. It will be readily phagocytized upon entering the host b. It will be unable to carry out aerobic respiration c. It will no longer be able to secrete exotoxins. d. It will be unable to adhere to host tissue and establish infection e. It will demonstrate increased resistance to antibiotics
d. It will be unable to adhere to host tissue and establish infection
________ is the physician first associated with vaccination. A) Koch B) Escherich C) Pasteur D) Jenner E) Lister
d. Jenner
Which of the following regarding antimicrobial control agents is FALSE? a. Some agents affect microbial cell membranes by dissolving lipids. b. Some agents kill by denaturing microbial cell proteins. c. Contaminating organic debris such as blood or sputum will decrease effectiveness. d. Most chemical agents can achieve sterility. e. Some agents are utilized as both an antiseptic and a disinfectant.
d. Most chemical agents can achieve sterility.
Which of the following does not kill endospores? a. Autoclaving b. Incineration c. Hot-air sterilization d. Pasteurization e. All of the above kill endospores.
d. Pasteurization
Which of the following is NOT a functionally analogous pair? a. Bacterial flagella; 9 + 2 flagella b. Peptidoglycan; cellulose c. 70s ribosomes; 80S ribosomes d. Pili; centrioles e. Circular bacterial chromosome; linear eukaryotic chromosomes
d. Pili; centrioles
Which of the following statements does NOT provide evidence for the endosymbiotic theory? a. The ribosomes contained within mitochondria and chloroplasts are very similar to prokaryotic ribosomes. b. Mitochondria and chloroplasts contain circular DNA, similar to the DNA in prokaryotes. c. The same antibiotics that inhibit protein synthesis in prokaryotes also inhibit protein synthesis within mitochondria and chloroplasts. d. Prokaryotes contain peptidoglycan in their cell walls.
d. Prokaryotes contain peptidoglycan in their cell walls.
Which of the following would most likely resist dessication and high pressure? a. Viruses b. Protozoans c. Molds d. Spore-forming bacteria
d. Spore-forming bacteria
Which of the following statements regarding biofilms is true? a. Biofilms occur in nature but rarely occur in human infections. b. Fortunately, biofilms are not an issue that impacts human health. c. The close proximity of microbes within a biofilm probably inhibits conjugation. d. The microbes in biofilms can work cooperatively to carry out complex tasks.
d. The microbes in biofilms can work cooperatively to carry out complex tasks.
While waiting for your meal at a restaurant, you read the information on the creamer containers at your table and notice that they do not need to be refrigerated. You are surprised, because dairy products typically must be kept cold to prevent spoilage. How were these products treated to eliminate microbial growth and prevent spoilage? a. Chemical preservatives b. Pasteurization c. Gamma irradiation d. Ultra-high-temperature (UHT) treatment
d. Ultra-high-temperature (UHT) treatment
You suggest to use a eukaryotic microorganism for a genetic experiment in lab but your classmate thinks is better to use bacteria. Why is your classmate correct? a. Bacteria are less complex than plants and animals. b. Bacterial life cycles can be very short. c. Some bacteria are very well studied and much is known about their genetic makeup. d. all of the above
d. all of the above
Which of the following processes are beneficial activities of microorganisms? a. recycling elements in the environment b. decomposing sewage c. producing foods and chemicals d. all of the listed responses are correct
d. all of the listed responses are correct
Prior to drawing blood for a blood donation, the nurse will clean the arm with a Betadine solution. This form of antimicrobial control is called __________. a. disinfection b. sterilization c. sanitization d. antisepsis
d. antisepsis
An organism is found in a deep-sea vent where the temperature is very high and the mineral content very unusual. The organism is unicellular, has no apparent nucleus, and has a cell wall but no peptidoglycan. This organism would be classified as which of the following types of organisms? a. bacteria b. algae c. virus d. archaea
d. archaea
All of the following are eukaryotes EXCEPT __________. a. algae b. helminths c. fungi d. bacteria e. protozoa
d. bacteria
Functions of the glycocalyx include all of the following EXCEPT a. source of nutrition. b. protection against dehydration. c. biofilm formation. d. binary fission. e. increased virulence.
d. binary fission.
All of the following are effective for destroying prions EXCEPT a. proteases. b. incineration. c. NaOH + autoclaving at 134°C. d. boiling. e. None of the answers are correct; each of these will destroy prions.
d. boiling.
A bacterial medium contains chemicals that inhibit gram-positive bacteria and indicators so that bacteria that ferment lactose produce red colonies, and bacteria that do not ferment lactose produce colorless colonies. Such a medium is called __________. a. selective b. enriched c. differential d. both selective and differential
d. both selective and differential
Which type of light microscopy is used to visualize stained specimens? a. darkfield b. phase-contrast c. compound d. brightfield e. binocular
d. brightfield
Robert Koch's studies on Bacillus anthracis established a sequence of experimental steps to prove that microbes __________. a. recycle elements such as nitrogen b. produce antiviral compounds c. control insect pests d. cause disease e. can be altered to produce products such as human insulin
d. cause disease
Three-dimensional images of live cells can be produced with: a. darkfield microscopy b. fluorescence microscopy c. transmission electron microscopy d. confocal microscopy e. phase-contrast microscopy
d. confocal microscopy
Which of the following is NOT a typical characteristic of most bacterial plasma membranes? a. contains proteins b. site of energy production c. is selectively permeable d. contains cholesterol e. composed of a phospholipid bilayer
d. contains cholesterol
Which of the following is an advantage of the standard plate count? a. provides immediate results b. can be performed on very dilute samples, such as lake water c. can be used to count heat-sensitive bacteria d. determines the number of viable cells e. can readily count cells that form aggregates
d. determines the number of viable cells
The __________ is the part of the microscope that controls the amount of light entering the condenser. a. objectives b. ocular lenses c. condenser d. diaphragm
d. diaphragm
What is the best definition of sterilization? a. removal of unwanted microorganisms b. elimination of bacteria c. removal of viruses d. elimination of all microorganisms
d. elimination of all microorganisms
Aseptic technique is a standard lab practice that includes all of the following EXCEPT __________. a. using careful methods to sterilize equipment used to transfer and isolate colonies b. preventing airborne contaminants from accessing nutrient-rich environments in cultures c. preventing contamination of unwanted microbes present on solids, in liquids, and in the air d. elimination of all oxygen during any processes to prevent contamination
d. elimination of all oxygen during any processes to prevent contamination
Commercial utilization of microbial products has become increasingly popular due to their environmentally friendly nature. Removal of these products from the environment typically utilizes a) organic solvents b) soap c) alcohol d) enzymes e) organic acids
d. enzymes
Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt? a. thermophiles b. anaerobes c. psychrophiles d. facultative halophiles e. hyperthermophiles
d. facultative halophiles
Which of the following types of microscopy allows organisms to be identified based on the presence of antigens, even if the organisms are inside a cell? a. scanning acoustic microscopy b. darkfield microscopy c. phase-contrast microscopy d. fluorescent microscopy
d. fluorescent microscopy
The chemical requirements for microbial growth include carbon, nitrogen, phosphorus, and sulfur. Why do all cells need nitrogen? a. as an energy source b. as part of the phospholipid bilayers that form the cell membranes c. for maintaining a favorable pH d. for building amino acids, proteins, and nucleic acids
d. for building amino acids, proteins, and nucleic acids
Consider organisms that are eukaryotic, are found in both unicellular and multicellular forms, may resemble plants but are not photosynthetic, have chitin in their cell walls, and absorb organic nutrients from decomposing material in the environment. These organisms would be classified as which of the following types of organisms? a. archaea b. bacteria c. protozoa d. fungi
d. fungi
A chemical that reduces spoilage in fruit by destroying fungi but does NOT appear to affect other microbes would be called a __________. a. fungistatic agent b. bactericidal agent c. sterilant d. fungicidal agent
d. fungicidal agent
Archaea differ from bacteria in that archaea ______ A) reproduce by binary fission. B) use organic compounds for food. C) lack nuclei. D) have diverse cell wall compositions. E) are prokaryotic.
d. have diverse cell wall compositions
The protection from disease provided by vaccination is called __________. a. asepsis b. antibiotic therapy c. gene therapy d. immunity
d. immunity
Each of the following statements concerning the gram-positive cell wall is true EXCEPT a. it is sensitive to penicillin. b. it contains teichoic acids. c. it maintains the shape of the cell. d. it protects the cell in a hypertonic environment. e. it is sensitive to lysozyme.
d. it protects the cell in a hypertonic environment.
The antibiotic polymyxin B combines with phospholipids. This will cause __________. a. stoppage of protein synthesis b. sporulation c. loss of motility d. leakage of intracellular contents e. binary fission
d. leakage of intracellular contents
What phase of the cell cycle is extended in a chemostat? a. death phase b. stationary phase c. lag phase d. log phase e. logarithmic decline phase
d. log phase
Which of the following phases of the bacterial growth curve is matched with the correct definition? a. stationary phase--the phase in which cells are not dividing very rapidly as they acclimatize to a new environment b. lag phase--the phase in which the death of organisms exceeds the production of new cells and the curve declines c. death phase--the phase in which the curve is flat; microbial deaths balance the number of new cells d. log phase--the phase in which organisms are actively dividing and the generation time is constant
d. log phase--the phase in which organisms are actively dividing and the generation time is constant
What metric unit would be most appropriate for expressing the size of most viruses? a. millimeter b. micrometer c. centimeter d. nanometer
d. nanometer
__________ is an example of an acidic dye; __________ is an example of a basic dye. a. safranin; methylene blue b. malachite green; eosin c. acid fuchsin; ink d. nigrosin; crystal violet
d. nigrosin; crystal violet
An unknown organism grows at the top of a tube of thioglycolate broth. This organism is best described as a(n) __________ for its oxygen requirements. a. facultative anaerobe b. obligate anaerobe c. microaerophile d. obligate aerobe e. aerotolerant anaerobe
d. obligate aerobe
Oxidizing agents, such as hydrogen peroxide, are useful for irrigating deep wounds, in which released oxygen will inhibit the growth of __________. a. obligate aerobes b. microaerophiles c. facultative anaerobes d. obligate anaerobes
d. obligate anaerobes
The first step for directly linking a microbe to a specific disease according to Koch's postulates is to ______ A) compare the blood of a sick animal to blood obtained from a healthy animal. B) isolate microbes from the blood of healthy animals. C) inject a sample of blood or other body fluid from a diseased animal into a healthy animal. D) obtain a sample of blood or other body fluid from a diseased animal. E) culture the blood or other body fluid from a diseased animal using nutrient medium.
d. obtain a sample of blood or other body fluid from a diseased animal.
Recently, silver has been considered in new applications for microbial control, such as impregnating surgical dressings and infusing food containers with silver. These new applications are important because silver is __________. a. useful as a surface-active agent b. effective as an oxidizing agent c. effective in dissolving lipids in the plasma membrane d. oligodynamic and unaffected by antimicrobial resistance
d. oligodynamic and unaffected by antimicrobial resistance
Niacin, when added to a medium, would be considered a(n) __________. a. reducing agent b. electron carrier c. carbon source d. organic growth factor e. enzyme cofactor
d. organic growth factor
The term describing bacteria with flagella distributed over the entire surface of the cell is __________. a. monotrichous b. amphytrichous c. lophotrichous d. peritrichous
d. peritrichous
A eukaryotic cell can ingest a prokaryotic cell by __________. a. pinocytosis b. digestive vacuolization c. active transport d. phagocytosis e. osmosis
d. phagocytosis
Algae are ____________. a. classified as prokaryotes b. photosynthetic c. classified as eukaryotes d. photosynthetic and classified as eukaryotes e. photosynthetic and classified as prokaryotes
d. photosynthetic and classified as eukaryotes
The __________ charge of a basic dye adheres to the __________ charge of bacterial cell surfaces. a. negative; acidic b. negative; positive c. positive; acidic d. positive; negative e. positive; basic
d. positive; negative
An organism displays some growth at 4°C and at 25°C. However, it grows best at 20°C. This organism would be classified as a __________. a. thermophile b. halophile c. mesophile d. psychrotroph e. psychrophile
d. psychrotroph
In the Gram stain, if the decolorizing step is deleted, gram-negative cells will appear __________ at the completion of the staining procedure. a. pink b. unstained c. green d. purple e. blue
d. purple
What factors contribute to the rising incidence of antibiotic resistance? a. random mutations in bacterial genomes b. overuse of the specific drugs c. overuse and misuse of specific drugs d. random mutations, overuse and misuse of specific drugs e. misuse of the specific drugs
d. random mutations, overuse and misuse of specific drugs
Overuse and misuse of antibiotics has __________. a. caused viruses to become resistant to a variety of antibiotics b. caused bacteria to acquire virulence factors and become more deadly c. caused bacteria to become resistant to household disinfectants, such as chlorine bleach d. selected for antibiotic-resistant strains of bacteria and increased their frequency in both the hospital environment and the community e. directly caused mutations in humans that make them allergic to the antibiotic
d. selected for antibiotic-resistant strains of bacteria and increased their frequency in both the hospital environment and the community
Consider a gram-positive cell in a hypertonic medium. If the peptidoglycan were damaged, the cell would __________. a. swell b. remain the same size c. shrink and then swell d. shrink
d. shrink
The term trace elements refers to a. the elements CHONPS. b. vitamins. c. nitrogen, phosphorus, and sulfur. d. small mineral requirements. e. toxic substances.
d. small mineral requirements.
Before bacteria can be identified, mixed cultures must be separated. What technique is used to separate bacteria and get individual colonies? a. differential media b. enriched media c. selective media d. streak plate
d. streak plate
When microbial control methods are used, microbes are destroyed at a constant rate; there is no instantaneous death of all the microbes present. That microbial death rate is influenced by all of the following factors EXCEPT __________. a. the microbial characteristics b. the number of microbes c. the time of exposure d. toxins produced by the microbe
d. toxins produced by the microbe
Packages of milk and coffee creamers may be stored without refrigeration if they have been sterilized by __________. a. autoclaving b. treatment with phenol c. boiling d. ultra-high-temperature (UHT) treatment e. high-temperature short-time (HTST) pasteurization
d. ultra-high-temperature (UHT) treatment
Acid-fast mycobacteria differ from non-acid-fast bacteria by the presence of __________. In the decolorizing step of the acid-fast stain, __________ is used. a. peptidoglycan; carbolfuchsin b. capsules; acetone-alcohol c. endospores; methylene blue d. waxy material in their cell walls; acid-alcohol
d. waxy material in their cell walls; acid-alcohol
In Figure 6.3, which tube shows the expected growth pattern for a microaerophile? a b c d e
e
Which of the following pairs is mismatched? a) metachromatic granules -- stored phosphates b) polysaccharide granules -- stored starch c) lipid inclusions -- poly-β-hydroxybutyric acid d) sulfur granules -- energy reserve e) ribosomes -- protein storage
e) ribosomes -- protein storage
Which of the following is not a distinguishing characteristic of prokaryotic cells? a) they usually have a single, circular chromosome b) they lack membrane-enclosed organelles c) they have cell walls containing preptidoglycan d) their DNA is not associated with histones e) they lack a plasma membrane
e) they lack a plasma membrane
Which of the following is false about fimbriae? a) they are composed of protein b) they may be used for attachment c) they are found on gram-negative cells d) they are composed of pilin e) they may be used for motility
e) they may be used for motility
HEPA filters are effective because they are designed to remove all airborne particulates, including microorganisms down to a. 10 nanometers. b. 1 micrometer. c. 0.01 micrometers. d. 10 micrometers. e. 0.3 micrometers.
e. 0.3 micrometers.
Which one of the following temperatures would most likely kill amesophile? a. −50°C b. 0°C c. 9°C d. 37°C e. 60°C
e. 60°C
The DRT for a particular bacterial species at 60°C is 30 minutes. How long would it take at this temperature to remove 99.9% of this bacterial population? a. 10 minutes b. 30 minutes c. 60 minutes d. 120 minutes e. 90 minutes
e. 90 minutes
Cocci may be arranged as __________. a. tetrads b. streptococci c. diplococcic d. staphylococci e. All of the listed answers.
e. All of the listed answers.
Members of the genus Clostridium display the following properties: - Gram-positive bacilli - Endospore formation - Anaerobic growth Which of the following would be appropriate for the culture of members of this genus? a. Blood agar plate in a candle jar b. Blood agar plate in an anaerobe jar c. Nutrient broth in a standard incubator d. Sodium thioglycolate broth e. Both a blood agar plate in an anaerobe jar and sodium thioglycolate broth
e. Both a blood agar plate in an anaerobe jar and sodium thioglycolate broth
Which of the following steps is common to both the Gram stain and the acid-fast stain? a. Steam exposure for stain penetration b. Acid-alcohol for decolorizing c. The application of iodine as a mordant d. The use of methylene blue as a counterstain e. Heat fixation of the smear before staining
e. Heat fixation of the smear before staining
With a light microscope, which of the following would allow discrimination between eukaryotes and prokaryotes? a. Observation of the plasma membrane b. Observation of the ribosomes c. Observation of flagella d. Observation of photosynthetic pigment e. Observation of nuclei
e. Observation of nuclei
Why is penicillin selectively toxic to bacterial cells but harmless to human cells? a. Penicillin is rapidly metabolized and destroyed by human cells. b. The glycocalyx of an animal cell provides a barrier through which penicillin cannot pass. c. Human cells actively transport penicillin out of the cell. d. Penicillin is inactivated within lysosomes of human cells. e. Penicillin specifically weakens peptidoglycan, which is found only in bacterial cells.
e. Penicillin specifically weakens peptidoglycan, which is found only in bacterial cells.
You are preparing a medium for growing fastidious bacteria and must add several heat-labile solutions of growth factors. Which of the following is an appropriate strategy for preparing and sterilizing this medium? a. Use dry heat to sterilize the medium. b. Use UV radiation to sterilize this medium. c. Prepare the medium, add the growth factors, and autoclave. d. Pasteurize the medium. e. Prepare and autoclave the medium before adding the growth factors.
e. Prepare and autoclave the medium before adding the growth factors.
Which of the following infectious agents challenge the current sterilization strategies that have been accepted and in use for decades? a. Endospores b. Mycobacteria c. HIV d. Methicillin-Resistant Staphylococcus aureus (MRSA) e. Prions
e. Prions
Which of the following is LEAST likely to be damaged by exposure to gamma radiation? a. Bacteria b. Viruses c. Fungi d. Protozoa e. Prions
e. Prions
Which of the following pairs is MISMATCHED? a. Endoplasmic reticulum; internal transport b. Golgi complex; secretion c. Mitochondria; ATP production d. Lysosome; digestive enzymes e. Ribosomes; storage
e. Ribosomes; storage
Who is credited with first observing cells? a. Robert Koch b. Carolus Linnaeus c. Louis Pasteur d. Anton van Leeuwenhoek e. Robert Hooke
e. Robert Hooke
Which of the following statements is NOT true for both TEM and SEM? a. The illuminating source is an electron beam. b. Both can be used to view specimens smaller than 0.2 micrometers. c. Black-and-white images are produced. d. The microscope is focused using electromagnetic lenses. e. The specimen must be sectioned before viewing.
e. The specimen must be sectioned before viewing
__________ is a compound found in antimicrobial soaps that targets gram-positive bacteria. a. Sodium nitrate b. Mercuric chloride c. Formaldehyde d. Hydrogen peroxide e. Triclosan
e. Triclosan
The following may be listed on the ingredient list of your favorite snack food. Which of these products is NOT antimicrobial? a. Calcium propionate b. Potassium sorbate c. Sorbic acid d. Sodium benzoate e. Xanthan
e. Xanthan
In Pasteur's swan-neck flask experiment, the importance of the S-shaped curves in the flasks was twofold. The curves allowed entry of air but excluded ___________. a. oxygen b. viruses c. heat d. nutrients e. airborne microorganisms
e. airborne microorganisms
Regarding Louis Pasteur's experiments with the S-neck flask, which of the following statements is TRUE? A) The possibility of contamination was removed. B) All preexisting microorganisms were killed. C) A food source was provided. D) Air exchange was involved. E) All of the answers are correct.
e. all of the answers are correct
Which of the following is a beneficial activity of microorganisms? a. some microorganisms are used as food for humans b. some microorganisms use carbon dioxide c. some microorganisms provide nitrogen for plant growth d. some microorganisms are used in sewage treatment processes e. all the above
e. all the above
Common commercial benefits of microorganisms include synthesis of a) aspirin b) antibiotics c) insulin d) antibiotics and aspirin e) antibiotics and insulin
e. antibiotic and insulin
A new microorganism has been isolated from hot springs in Yellowstone National Park. It consists of single cells, which appear to lack a nucleus. Chemical analysis shows the presence of both DNA and RNA in the cytoplasm and pseudomurein in the cell wall. In which of the following groups will this organism be classified? a. fungi b. bacteria c. protists d. plants e. archaea
e. archaea
Antibiotics are produced by ______ A) bacteria. B) protozoa. C) fungi. D) viruses. E) bacteria and fungi.
e. bacteria and fungi
All of the following are examples of microbial control using heavy metals EXCEPT __________. a. burn treatment using silver-sulfadiazine ointment b. algae control in swimming pools using copper sulfate c. mouthwash solution containing zinc chloride d. antiseptic solution containing mercurochrome e. benzoyl peroxide used for acne treatment
e. benzoyl peroxide used for acne treatment
Through metabolism, pathogens often produce acids that interfere with their own growth. __________ are/is added to media to control pH changes. a. pH indicators b. growth inhibitors c. saline d. vinegar e. buffers
e. buffers
A culture medium consisting of agar, peptone, and beef-heart extract is a(n) __________. a. differential medium b. chemically defined medium c. selective medium d. enrichment medium e. complex medium
e. complex medium
The nucleoid (nuclear area) of the bacterial cell __________. a. is enclosed in a nuclear membrane b. has abundant histone proteins c. contains many linear chromosomes d. is connected to the endoplasmic reticulum e. contains the bacterial chromosome
e. contains the bacterial chromosome
All of the following methods are used for food preservation EXCEPT __________. a. deep freezing b. dessication c. osmotic pressure d. commercial canning e. direct flaming
e. direct flaming
Which microscope achieves the highest magnification and greatest resolution? a. darkfield microscope b. phase-contrast microscope c. compound light microscope d. fluorescence microscope e. electron microscope
e. electron microscope
Which of the following pairs is mismatched? a. darkfield microscope - uses visible light b. scanning electron microscope - produces a three-dimensional image c. confocal microscope - produces a three-dimensional image d. scanning tunneling microscope - allows visualization of atoms e. fluorescence microscope - uses a fluorescent light
e. fluorescence microscope - uses a fluorescent light
Your lab partner tells you the bacteria are moving in his Gram-stained smear. You can conclude that __________. a. the bacteria are gram-negative b. the bacteria have capsules c. he did a flagella stain, not a Gram stain d. the bacteria are acid-fast e. he didn't properly fix the smear
e. he didn't properly fix the smear
The major food producers for other living organisms is/are ______ A) higher plants. B) cyanobacteria. C) algae. D) higher plants and algae. E) higher plants, cyanobacteria, and algae.
e. higher plants, cyanobacteria, and algae.
All of the following are found in the cell walls of gram-positive bacteria EXCEPT __________. a. peptidoglycan b. teichoic acid c. N-acetylglucosamine d. lipoteichoic acid e. lipid A
e. lipid A
Which of the following is NOT a step in binary fission? a. invagination of the plasma membrane b. replication of chromosomal DNA c. cell elongation d. cross-wall formation e. lysis of the existing cell wall
e. lysis of the existing cell wall
Bacteria growing in and on the human body, including normal microbiota as well as pathogens, are classified as __________. a. thermophilic and acidophilic b. mesophilic and halophilic c. thermophilic and halophilic d. mesophilic and acidophilic e. mesophilic and heterotrophic
e. mesophilic and heterotrophic
Mycology is the study of ______ A) molds. B) mycoplasma. C) mushrooms. D) protozoa. E) molds, yeast, and mushrooms.
e. molds, yeast, and mushrooms
Phototaxis refers to the ability of microorganisms to __________. a. move toward or away from chemical stimuli b. move in a wavelike motion c. attach to solid surfaces d. survive under adverse conditions e. move toward a source of light.
e. move toward a source of light.
Each of the following organisms would be considered a microbe EXCEPT: a. Bacterium b. Virus c. Yeast d. Protozoan e. Mushroom
e. mushroom
Which of the following pairs is mismatched? a. capsule - negative stain b. cell arrangement - simple stain c. cell size - negative stain d. Gram stain - bacterial identification e. none of the above
e. none of the above
___________ is the study of protozoa. a. bacteriology b. mycology c. immunology d. virology e. parasitology
e. parasitology
Bone and tendons for transplant are decontaminated by a. glutaraldehyde. b. ethylene oxide. c. peroxygens. d. plasma sterilization. e. supercritical fluids.
e. supercritical fluids.
Recombinant DNA technology has become an increasingly important part of our life. It is used for all of the following EXCEPT ______ A) vaccine production. B) increasing the nutritional value of food. C) drug production. D) enhancing food longevity. E) synthesis of water.
e. synthesis of water
Assume you are growing a bacterial culture in a glucose medium. Your lab partner adds more glucose in hopes of speeding up the experiment. The bacteria suddenly die. The best explanation for this result is that __________. a. glucose is toxic to bacteria b. the bacteria could not use glucose c. osmotic lysis occurred d. the cells underwent sporulation e. the cells plasmolyzed
e. the cells plasmolyzed
You discover a compound that you suspect reduces spoilage in fruit. You treat apples with your compound and inoculate them with Botrytis, a common spoilage fungus. After 7 days, the dry weight of fungi is 5 mg on the treated apples and 10 mg on the untreated apples. You conclude from these results that __________. a. apple spoilage is caused by fungi b. the compound is toxic to humans c. the compound kills fungi d. the fungus probably will have no effect on the apples e. the compound is fungistatic
e. the compound is fungistatic
The usefulness of antibiotics is hampered by ___________. a. their inability to kill gram negative bacteria b. difficulties encountered in mass production c. the limited types of antibiotics available d. an antibiotic's lack of specificity for bacterial versus animal cells e. the emergence of antibiotic-resistant bacteria
e. the emergence of antibiotic-resistant bacteria
Which of the following kinds of microscopy would be most appropriate for viewing the presence and distribution of mitochondria in a protozoan cell? a. darkfield microscopy b. phase-contrast microscopy c. brightfield microscopy d. scanning electron microscopy e. transmission electron microscopy
e. transmission electron microscopy
Which of the following is NOT a method used for the direct measurement of microbial growth? a. filtration b. serial dilutions c. the most probable number (MPN) method d. spread plates e. turbidity
e. turbidity
Development of emerging infectious disease can be a result of all of the following EXCEPT ______ A) modern transportation. B) changes in the environment. C) microbial mutation. D) overuse of antibiotics. E) use of genetically modified foods.
e. use of genetically modified foods
Resolution is very good when using an electron microscope because the __________ of the electron beam is much shorter than that of visible light. a. frequency b. penetration c. absorption d. reflection e. wavelength
e. wavelength
Instead of oxygen, __________ may utilize nitrate or sulfate as their final electron acceptors. a. obligate aerobes b. halophiles c. facultative anaerobes d. microaerophiles e. aerotolerant anaerobes f. obligate anaerobes
f. obligate anaerobes
Bacteria that can grow in the presence or absence of Oxygen are called:
facultative anaerobes
Acid-fast bacteria demonstrate unique staining properties because of a special protein layer found in their cell walls. true or false
false
Aerotolerant organisms can grow in the presence of oxygen because their cell wall protects them from toxic products of oxygen. true or false
false
Any process that destroys the non-spore forming contaminants on inanimate objects is sterilization. true or false
false
Bacterial motility and flagellar movement can readily be viewed using transmission electron microscopy. true or false
false
Bovine spongiform encephalitis (BSE, or "mad cow disease") is caused by a virus: - true or false
false
Cells placed in a hypotonic solution tend to lose water due to osmotic pressure. true of false
false
Desiccation is a reliable form of sterilization. true or false
false
Endospores are a reproductive structure. true or false
false
If acid-fast bacteria are stained with the Gram stain, they will stain gram-negative. true or false
false
In a direct microscopic count, dead cells are easily differentiated from live cells. true or false
false
In performing a ten-fold dilutions series from a sample containing 10,000 bacteria per milliliter, the fourth tube in the dilution series will have 10 cells per milliliter. true or false
false
Iodine is one of the LEAST effective antimicrobial chemicals, effective only against certain very sensitive strains of bacteria. true or false
false
Magnification is the quality of the microscope that allows one to distinguish between two points that are very close together. true or false
false
Many enzymes in both prokaryotic and eukaryotic cells are compartmentalized within organelles. true or false
false
Microaerophiles do NOT require oxygen for growth. true or false
false
Microorganisms placed in high concentrations of salts and sugars undergo lysis. true or false
false
Most pathogenic bacteria are thermophiles. true or false
false
Most viruses are highly resistant to disinfectants and antiseptics. true or false
false
Penicillin is more effective against gram-negative bacteria than against gram-positive bacteria because it specifically interferes with the synthesis of lipopolysaccharides. true or false
false
What is the correct list, in increasing order, of the resistance of microorganisms to chemical biocides?
gram-positive bacteria, fungi, endospores, prions
Each of the three graphs shown below includes data collected during exponential growth of a species of bacteria grown in three different growth conditions. Which growth condition resulted in the longest generation time?
growth condition C
What types of microbes would a microbiologist use culture techniques for living host cells?
obligate intracellular organisms, like chlamydia or viruses.
A disease that has increased in incidence or could increase in incidence in the near future is called an emerging infectious disease: - true and false
true
