MBS PRACTICE TEST 2

Which pairing is correct? A. Fungi — prokaryotic B. Bacteria — eukaryotic C. Fungi — eukaryotic D. Archaea — eukaryotic

C. Fungi — eukaryotic

Which feature is shared by all three domains of life? A. Nucleus B. Peptidoglycan C. Ribosomes D. Membrane-bound organelles

C. Ribosomes

Which statement about binomial nomenclature is correct? A. It uses species and family B. It uses genus and specific epithet C. It uses kingdom and genus D. It uses genus and strain

B. It uses genus and specific epithet

A scientist observes that disease consistently occurs when a particular microorganism is isolated from diseased individuals. Which concept is this investigation most closely related to? A. Koch's postulates B. Germ theory only C. Spontaneous generation D. Biogenesis

A. Koch's postulates

Which is a limitation of Koch's postulates mentioned in the study guide? A. They cannot identify microorganisms B. They do not account well for asymptomatic individuals C. They only apply to viruses D. They cannot be used with bacteria

B. They do not account well for asymptomatic individuals

Which statement correctly compares normal microbiota and pathogens? A. Normal microbiota always cause disease B. Pathogens never live in humans C. Pathogens can cause disease, while microbiota may or may not cause disease D. Normal microbiota and pathogens are identical

C. Pathogens can cause disease, while microbiota may or may not cause disease

A microorganism attaches to a host cell using specialized structures called: A. Capsules B. Adhesins C. Endospores D. Ribosomes

B. Adhesins

A disease develops gradually and resolves slowly over an extended period. This is most consistent with a: A. Acute infection B. Chronic infection C. Opportunistic infection D. Primary infection

B. Chronic infection

Which statement correctly compares LD50 and ID50? A. LD50 measures infection and ID50 measures death B. LD50 measures the amount that kills 50%; ID50 measures the amount that infects 50% C. Both measure mortality D. Both measure infection

B. LD50 measures the amount that kills 50%; ID50 measures the amount that infects 50%

Which pathogen would have a broader host range? A. One that infects only humans B. One that infects humans, dogs, and several other mammals C. One that infects only dogs D. One that infects only one species

B. One that infects humans, dogs, and several other mammals

Which is an example of a symptom? A. Blood pressure measured at 150/90 B. Fever measured at 102°F C. Headache reported by the patient D. Redness observed by a physician

C. Headache reported by the patient

Damage caused by the host's immune response to a pathogen is an example of: A. Colonization B. Immunopathogenesis C. Transmission D. Incubation

B. Immunopathogenesis

During which stage of infectious disease do general, nonspecific symptoms often appear before the characteristic illness? A. Incubation B. Prodromal C. Illness D. Convalescence

B. Prodromal

Which example represents indirect contact transmission? A. A mother transmitting a pathogen to her fetus B. A person coughing directly onto another person C. Touching a contaminated object D. A mosquito transmitting a pathogen

C. Touching a contaminated object

Which is an example of a vehicle of transmission? A. Contaminated water B. Mosquito C. Contaminated doorknob D. Direct physical contact

A. Contaminated water

Which statement about a reservoir is correct? A. It is always a human host B. It is only an inanimate object C. It is a place where a pathogen normally lives and can be maintained D. It is always a vector

C. It is a place where a pathogen normally lives and can be maintained

Which microscope would be particularly useful for viewing the surface and obtaining a three-dimensional appearance of a microorganism? A. TEM B. SEM C. Brightfield microscope D. Phase-contrast microscope

B. SEM

A TEM would be particularly useful for observing: A. The surface of a microorganism B. Internal structures C. Living cells D. Colony color

B. Internal structures

A microscope has a 10× ocular lens and a 40× objective. What is the total magnification? A. 40× B. 50× C. 400× D. 4,000×

C. 400×

Which property of microscopy is most directly concerned with the ability to distinguish two objects that are very close together? A. Magnification B. Resolution C. Contrast D. Refraction

B. Resolution

Which change would generally improve resolution in light microscopy? A. Using a longer wavelength B. Using a shorter wavelength C. Decreasing magnification D. Removing the objective lens

B. Using a shorter wavelength

Which interaction occurs when light is taken up by an object rather than transmitted through it? A. Reflection B. Refraction C. Absorption D. Scattering

C. Absorption

A student performs a Gram stain in the following order: crystal violet → iodine → safranin → alcohol. What is wrong? A. The primary stain should be omitted B. Iodine should be used after safranin C. The decolorizer should be used before the counterstain D. Safranin should be used before crystal violet

C. The decolorizer should be used before the counterstain

What is the purpose of the mordant in the Gram stain? A. It removes the primary stain B. It helps fix the primary stain complex in the cell C. It stains the background D. It destroys the cell wall

B. It helps fix the primary stain complex in the cell

After the decolorization step, what is expected? A. Both Gram-positive and Gram-negative cells are purple B. Gram-positive cells remain purple while Gram-negative cells lose the primary stain C. Gram-positive cells become pink while Gram-negative cells remain purple D. Both types become colorless

B. Gram-positive cells remain purple while Gram-negative cells lose the primary stain

Which statement about acid-fast staining is correct? A. Acid-fast bacteria are identified because of their mycolic acid-rich envelope B. Acid-fast bacteria lack cell walls C. Acid-fast staining is only used for fungi D. Acid-fast bacteria contain LPS

A. Acid-fast bacteria are identified because of their mycolic acid-rich envelope

Which staining technique is most useful when you want to observe the size and shape of a cell without heavily staining the cell itself? A. Negative stain B. Gram stain C. Acid-fast stain D. Endospore stain

A. Negative stain

A bacterial population is rapidly increasing at a constant rate on a growth curve. Which phase is this? A. Lag B. Log/exponential C. Stationary D. Death

B. Log/exponential

A bacterial culture has stopped increasing in total population because nutrient depletion and waste accumulation balance cell reproduction. Which phase is occurring? A. Lag B. Log/exponential C. Stationary D. Death

C. Stationary

Which scenario BEST represents bioremediation? A. Bacteria are used to break down an oil contaminant in polluted soil B. Bacteria are stained with crystal violet C. Bacteria are grown on nutrient agar D. Bacteria are viewed with an electron microscope

A. Bacteria are used to break down an oil contaminant in polluted soil