MMG 301 - Unit 3 Exam questions with
100% correct answers 2025/2026
What are the typical sources of specimens? - correct answer ✔✔- Blood (look for bacteremia or
viremia; can also test blood for the presence of antibodies to a pathogen)
- Urine (bacteriuria: presence of bacteria in urine; most often detected using urinalysis dip stick
or growth-dependent methods)
- Feces (look for intestinal pathogens; bacteria or eukaryotes)
- Abscesses and wounds (swab or needle aspiration)
- Throat/Nasal Swab (soft cottons swabs to collect samples to test for bacteria or viruses)
- Genital samples (to get specimens to test for sexually transmitted pathogens)
Be able to state the medical terms for bacteria in the blood and urine. - correct answer ✔✔-
Bacteremia = bacteria in the blood
- Bacteriuria = bacteria in the urine
Know the Biosafety levels for laboratories working with pathogens - correct answer ✔✔BSL =
biosafety level; classifications based on levels of risk; higher numbers are for more dangerous
pathogens
BSL 1 = few safety controls; open lab bench; non-pathogenic organisms; limited access
BSL 2 = can have open bench, but gloves, lab coat, eye protection required; used for moderate
pathogens
BSL 3 = designed for pathogens; organisms manipulated in biological safety cabinets; room
under slight negative pressure; extensive filtration of air
,BSL 4 = used for life-threatening pathogens that an be transmitted by aerosols; pressurized suits
for workers; Ebola, Marburg viruses
Be able to discern the difference between differential and selective media. - correct answer
✔✔selective media = contains substances that inhibit growth of certain types of bacteria
differential media = includes compounds that allows visualization of certain biochemical
pathways and products
Describe the three common methods used to test sensitivity of a pathogen to an antibiotic. -
correct answer ✔✔1. Minimum inhibitory concentration (MIC) = using tube dilution assay; MIC
is where no growth occurs
2. Disk diffusion assay = pure culture is spread on plate; then disks containing different
antibiotics are placed on plate. Also called a Kirby-Bauer test. Sensitivity is read by how big the
circle is around the organism. The bigger the circle, the more susceptible. The smaller or lack of
a circle means it is resistant.
3. "Etest" = MIC is read from the edge of the clear zone using the scale on the strips.
Know how the fundamental features of antibodies can be leveraged for diagnostic purposes. -
correct answer ✔✔
Understand that different serotypes of a particular pathogen can have different antigenic
properties and be able to describe specific examples. - correct answer ✔✔
Define an antibody titer and how it changes during the course of an infectious disease. - correct
answer ✔✔Antibody titer = the lowest concentration of serum at which an antibody-antigen
reaction is observed
,There is a decline with time after each immunization (resolution).
How is a Mantoux skin test performed and how is it interpreted. - correct answer ✔✔Mantoux
skin test is commonly used for testing of previous exposure or current infection with
Mycobacterium Tuberculosis.
Mtb is inserted underneath the skin and left under there for a few days. After a few days, it is
come back to be read by a physician. If an inflammatory response has occurred (i.e.,redness,
swelling, etc.) that means you currently have or had the disease. If no change occurs, you are
not infected.
False positives can result if you have been vaccinated for TB and the test will pick up the vaccine
resulting in redness and swelling even though you are not infected.
Define serology - correct answer ✔✔the diagnostic examination of blood serum, especially with
regard to the response of the immune system to pathogens
the use of antigen-antibody reactions to detect antigens and antibodies
Describe what an epitope is - correct answer ✔✔the part of an antigen molecule to which an
antibody attaches itself; found on glycoproteins and other molecules
Understand how agglutination assays are used to detect antibodies or antigens from a patient -
correct answer ✔✔Agglutination reactions use antigens that are attached to large particles or
whole cells to produce visible clumping and aggregation.
Agglutination = soluble antibodies cause clumping of antigens that are on the surface of a
synthetic particle or cell
, Agglutination uses synthetic latex beads coated with antibodies to a protein found on the
surface of Staphylococcus aureus cells.
Used in blood typing (blood cells clump together = hemagglutination) and serotyping (clumping
of bacterial cells)
direct EIA - correct answer ✔✔EIA = Enzyme Immunosorbent Assays
Direct = immunoassays use immobilized antibody to test for an antigen from the patient
(detecting antigens)
Indirect = immunoassays use immobilized antigen to detect antibodies from a patient (detecting
antibodies)
Know how PCR can be used to identify pathogen DNA in a patient - correct answer ✔✔PCR =
based diagnostic methods ask a simple question; Does the patient sample contain DNA of a
specific pathogen?
Strategy = provide diagnostic primers into a PCR reaction that will give a specific PCR double-
stranded DNA product only if there is pathogen DNA (template DNA) in the patient sample.
PCR product is only made if the primers exactly base-pair with pathogen DNA
- PCR primer sequences exactly base pair with pathogen DNA = PCR product made (+)
- PCR primer sequences do NOT base pair with pathogen DNA = No PCR product (-)
Briefly describe what qPCR is and how it works - correct answer ✔✔qPCR = quantitative real-
time PCR
Requires:
100% correct answers 2025/2026
What are the typical sources of specimens? - correct answer ✔✔- Blood (look for bacteremia or
viremia; can also test blood for the presence of antibodies to a pathogen)
- Urine (bacteriuria: presence of bacteria in urine; most often detected using urinalysis dip stick
or growth-dependent methods)
- Feces (look for intestinal pathogens; bacteria or eukaryotes)
- Abscesses and wounds (swab or needle aspiration)
- Throat/Nasal Swab (soft cottons swabs to collect samples to test for bacteria or viruses)
- Genital samples (to get specimens to test for sexually transmitted pathogens)
Be able to state the medical terms for bacteria in the blood and urine. - correct answer ✔✔-
Bacteremia = bacteria in the blood
- Bacteriuria = bacteria in the urine
Know the Biosafety levels for laboratories working with pathogens - correct answer ✔✔BSL =
biosafety level; classifications based on levels of risk; higher numbers are for more dangerous
pathogens
BSL 1 = few safety controls; open lab bench; non-pathogenic organisms; limited access
BSL 2 = can have open bench, but gloves, lab coat, eye protection required; used for moderate
pathogens
BSL 3 = designed for pathogens; organisms manipulated in biological safety cabinets; room
under slight negative pressure; extensive filtration of air
,BSL 4 = used for life-threatening pathogens that an be transmitted by aerosols; pressurized suits
for workers; Ebola, Marburg viruses
Be able to discern the difference between differential and selective media. - correct answer
✔✔selective media = contains substances that inhibit growth of certain types of bacteria
differential media = includes compounds that allows visualization of certain biochemical
pathways and products
Describe the three common methods used to test sensitivity of a pathogen to an antibiotic. -
correct answer ✔✔1. Minimum inhibitory concentration (MIC) = using tube dilution assay; MIC
is where no growth occurs
2. Disk diffusion assay = pure culture is spread on plate; then disks containing different
antibiotics are placed on plate. Also called a Kirby-Bauer test. Sensitivity is read by how big the
circle is around the organism. The bigger the circle, the more susceptible. The smaller or lack of
a circle means it is resistant.
3. "Etest" = MIC is read from the edge of the clear zone using the scale on the strips.
Know how the fundamental features of antibodies can be leveraged for diagnostic purposes. -
correct answer ✔✔
Understand that different serotypes of a particular pathogen can have different antigenic
properties and be able to describe specific examples. - correct answer ✔✔
Define an antibody titer and how it changes during the course of an infectious disease. - correct
answer ✔✔Antibody titer = the lowest concentration of serum at which an antibody-antigen
reaction is observed
,There is a decline with time after each immunization (resolution).
How is a Mantoux skin test performed and how is it interpreted. - correct answer ✔✔Mantoux
skin test is commonly used for testing of previous exposure or current infection with
Mycobacterium Tuberculosis.
Mtb is inserted underneath the skin and left under there for a few days. After a few days, it is
come back to be read by a physician. If an inflammatory response has occurred (i.e.,redness,
swelling, etc.) that means you currently have or had the disease. If no change occurs, you are
not infected.
False positives can result if you have been vaccinated for TB and the test will pick up the vaccine
resulting in redness and swelling even though you are not infected.
Define serology - correct answer ✔✔the diagnostic examination of blood serum, especially with
regard to the response of the immune system to pathogens
the use of antigen-antibody reactions to detect antigens and antibodies
Describe what an epitope is - correct answer ✔✔the part of an antigen molecule to which an
antibody attaches itself; found on glycoproteins and other molecules
Understand how agglutination assays are used to detect antibodies or antigens from a patient -
correct answer ✔✔Agglutination reactions use antigens that are attached to large particles or
whole cells to produce visible clumping and aggregation.
Agglutination = soluble antibodies cause clumping of antigens that are on the surface of a
synthetic particle or cell
, Agglutination uses synthetic latex beads coated with antibodies to a protein found on the
surface of Staphylococcus aureus cells.
Used in blood typing (blood cells clump together = hemagglutination) and serotyping (clumping
of bacterial cells)
direct EIA - correct answer ✔✔EIA = Enzyme Immunosorbent Assays
Direct = immunoassays use immobilized antibody to test for an antigen from the patient
(detecting antigens)
Indirect = immunoassays use immobilized antigen to detect antibodies from a patient (detecting
antibodies)
Know how PCR can be used to identify pathogen DNA in a patient - correct answer ✔✔PCR =
based diagnostic methods ask a simple question; Does the patient sample contain DNA of a
specific pathogen?
Strategy = provide diagnostic primers into a PCR reaction that will give a specific PCR double-
stranded DNA product only if there is pathogen DNA (template DNA) in the patient sample.
PCR product is only made if the primers exactly base-pair with pathogen DNA
- PCR primer sequences exactly base pair with pathogen DNA = PCR product made (+)
- PCR primer sequences do NOT base pair with pathogen DNA = No PCR product (-)
Briefly describe what qPCR is and how it works - correct answer ✔✔qPCR = quantitative real-
time PCR
Requires:
