Bio 171 Final Exam 50 QUESTIONS AND
CORRECT DETAILED ANSWERS WITH
RATIONALES (VERIFIED ANSWERS) ALREADY
GRADED A+ 2025 NEW UPDATE
A researcher is looking to determine the source of contamination of a patient that
presented with symptoms of food poisoning . To best determine between E. coli or
Salmonella as the cause , what type of agar will be used to isolate the growth of each ?
a. Differential Media
b. Enriched Media
c. Selective Media
d. Selective and Differential Media - CORRECT ANSWER: A. Differential Media
A researcher is looking to solidify an agent for growth media. What polysaccharide
substance would he/she use?
a. Agar
b. Beef abstract
c. Peptone
d. Yeast - CORRECT ANSWER: a. Agar
After a microbiologist obtains a quadrant streak sample, what is the next action taken in
the incubation process to obtain growth? - CORRECT ANSWER: The plate must be
incubated at 37°C for at least 12 hours with the lid on and must be placed upside down
Bacteria that have a CURVED rod morphology are referred to as - CORRECT
ANSWER: Vibrio
, Bacteria that have a ROD-like morphology are referred to as - CORRECT ANSWER:
Bacillus
Briefly explain how a Scanning Electron Microscope ( SEM ) forms an image of
subcellular organelles , substrates , and viral particles .
TEM - CORRECT ANSWER: When using an SEM the samples are coated with gold or
palladium, then exposed to a beam of electrons that reflects off the surface of the
specimen creating a 3-D image
When using a TEM, the sample is sliced very thinly and the electron passes through
sample visualizing organelles, substrates, and viral particles
Describe the ONE main differences between lytic and temperate phages . - CORRECT
ANSWER: Lytic phage replicate inside the host cell bacteria until lysis and the host cell
ruptures, while temperate page does not replicate inside the cell but integrates itself into
the host cell DNA and doesn't kill the host cell.
Describe the primary distinction between prokaryotic and eukaryotic cells - CORRECT
ANSWER: Eukaryotic cell contains a nucleus that houses the genetic component of the
organism, while prokaryotic cells do not have a nucleus and their DNA is found in the
cytoplasm
Describe the TWO main characteristics of Lysogenic (temperate) bacteriophage
replication - CORRECT ANSWER: It doesn't replicate and does not kill the host cell
It integrates itself into the host genome and multiplies with the host cell as the host cell
multiples.
Describe TWO differences between DNA and RNA . - CORRECT ANSWER: DNA is
double-stranded which forms a double helix while RNA is single-stranded. Also, DNA
contains deoxyribose sugar while RNA contains ribose.
CORRECT DETAILED ANSWERS WITH
RATIONALES (VERIFIED ANSWERS) ALREADY
GRADED A+ 2025 NEW UPDATE
A researcher is looking to determine the source of contamination of a patient that
presented with symptoms of food poisoning . To best determine between E. coli or
Salmonella as the cause , what type of agar will be used to isolate the growth of each ?
a. Differential Media
b. Enriched Media
c. Selective Media
d. Selective and Differential Media - CORRECT ANSWER: A. Differential Media
A researcher is looking to solidify an agent for growth media. What polysaccharide
substance would he/she use?
a. Agar
b. Beef abstract
c. Peptone
d. Yeast - CORRECT ANSWER: a. Agar
After a microbiologist obtains a quadrant streak sample, what is the next action taken in
the incubation process to obtain growth? - CORRECT ANSWER: The plate must be
incubated at 37°C for at least 12 hours with the lid on and must be placed upside down
Bacteria that have a CURVED rod morphology are referred to as - CORRECT
ANSWER: Vibrio
, Bacteria that have a ROD-like morphology are referred to as - CORRECT ANSWER:
Bacillus
Briefly explain how a Scanning Electron Microscope ( SEM ) forms an image of
subcellular organelles , substrates , and viral particles .
TEM - CORRECT ANSWER: When using an SEM the samples are coated with gold or
palladium, then exposed to a beam of electrons that reflects off the surface of the
specimen creating a 3-D image
When using a TEM, the sample is sliced very thinly and the electron passes through
sample visualizing organelles, substrates, and viral particles
Describe the ONE main differences between lytic and temperate phages . - CORRECT
ANSWER: Lytic phage replicate inside the host cell bacteria until lysis and the host cell
ruptures, while temperate page does not replicate inside the cell but integrates itself into
the host cell DNA and doesn't kill the host cell.
Describe the primary distinction between prokaryotic and eukaryotic cells - CORRECT
ANSWER: Eukaryotic cell contains a nucleus that houses the genetic component of the
organism, while prokaryotic cells do not have a nucleus and their DNA is found in the
cytoplasm
Describe the TWO main characteristics of Lysogenic (temperate) bacteriophage
replication - CORRECT ANSWER: It doesn't replicate and does not kill the host cell
It integrates itself into the host genome and multiplies with the host cell as the host cell
multiples.
Describe TWO differences between DNA and RNA . - CORRECT ANSWER: DNA is
double-stranded which forms a double helix while RNA is single-stranded. Also, DNA
contains deoxyribose sugar while RNA contains ribose.
