MCB 100 UIUC Final Exam (Exam 4) UPDATED ACTUAL and
Correct Answers
Question: The microbial growth curve has four phases
Answer:
lag, log, stationary, and death.
If a chemical could prevent microbial cell division, in which phase of growth
would it be most effective?: The log phase
Question: Considering the cell structure of mycoplasmas and other bacteria that stain
either Gram negative, Gram positive, or with acid-fast stains, which group
should you expect relies most on the presence of peptidoglycan for strength?-
Answer:
Gram-positive bacteria
Question: What is the function of tRNA during the process of translation?
Answer:
tRNA brings amino
acids to a growing chain of amino acids in ribosomes
Question: What is the difference between prokaryotic and eukaryotic ribosomes?
Answer:
-
Prokaryotic ribosomes consist of a 50S large and a 30S small subunit, while eukaryotic ribosomes
consist of a 60S
large and a 40S small subunit.
Question: Match the following descriptions of cellular structures with the type of cell
in which they are found.: Archaea: Hami, Protein cell wall
Bacteria: Peptidoglycan cell wall
Eukaryotes
Answer:
Organelles, 80S ribosome in cytosol
Question: Dr. Paul Ehrlich observed that the differential stain developed by Dr. Gram
suggested bacteria could be killed differentially by chemicals (Chapter 1). He
called these potential antibacterial agents "magic bullets".
Which among the following cell features of bacteria are potential targets for
,Dr. Ehrlich's "magic bullets" due to significant difference or absence from
humans? Choose all that apply.
Answer:
Ribosome and Cell wall
Question: Bacterial Structures... Label the structures of this bacterial cell. Drag the
appropriate labels to their respective locations.
Answer:
(From left to right)
DNA, Ribosome, Glycocalyx, Cell wall, Cytoplasmic Membrane
Question: The ____________ is a defining characteristic of bacteria which is not found in
eukaryotes and is therefore a good choice for chemotherapeutic agents.
View Available Hint(s)
Answer:
Peptidoglycan cell wall
Question: The cytosol of bacteria contain ____________ which has/have components
different from those of the functionally equivalent structure of eukaryotes.
View Available Hint(s)
Answer:
70S ribosomes
Question: What is meant by selective toxicity?
Answer:
Chemotherapeutic agents should act against the pathogen
and not the host.
Question: Why are chemotherapeutic agents that work on the peptidoglycan cell wall
of bacteria a good choice of drug?
Answer:
Humans and other animal hosts lack peptidoglycan cell walls.
Question: Why is polymyxin only used on the skin?
Answer:
It can also damage living human cell membranes,
but the drug is safely used on the skin, where the outer layers of cells are dead.
,Question: Quinolones and fluoroquinolones act against what bacterial target?
Answer:
DNA
gyrase
Question: Why is it difficult to find good chemotherapeutic agents against viruses?
Answer:
-
Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host
cell unaffected.
Question: Why do the beta-lactam drugs affect bacteria but NOT human cells?
Answer:
The
beta-lactam antibiotics act on bacterial cell walls; human cells do not have cell walls.
Question: A drug such as imipenem is chemically modified from penicillin. What are
non-natural drugs developed from natural drugs called?
Answer:
Semi-synthetics
Question: Typically, beta-lactam drugs affect the peptidoglycan layer on bacteria.
Why would beta-lactam drugs typically be considered more active against
Gram-positive bacteria and less so against Gram-negative bacteria?
Answer:
The cell walls
of Gram-positive bacteria have a thick peptidoglycan component.
Question: What effect does penicillin have on susceptible bacterial cells?
Answer:
Penicillin disrupts
cell wall synthesis.
Question: An antimicrobial that inhibits bacterial cell wall synthesis will result in which
of the following?
Answer:
Bacterial cells become more susceptible to osmotic pressure.
, Question: Classical pasteurization heats the fluid to about ___С for a time of about___-
Answer:
minutes
Question: Geogemma barossii is a hyperthermophilic archaeon that grows near hydrothermal vents in
the ocean at temperatures as high as 121С. What effect
would standard autoclaving have on this microbe?
Answer:
Nothing
Question: Boiling for ten minutes does not kill ___
Answer:
Endospores
Question: Heating a broth culture of microorganisms to 140C for three seconds would
___ the culture.
Answer:
Sterilize
Question: It has been determined that the temperature in an autoclave should reach
__________ for sterilization.
Answer:
121 degrees Celsius
Question: What role does pressure play in an autoclave?
Answer:
Pressure is applied to boiling water to
prevent heat from escaping as steam.
Question: How do scientists ensure that autoclaved materials were actually sterilized?
Answer:
They may place a sterility indicator with a special dye to detect the growth of endospores.
Question: What is the purpose of an autoclave?
Answer:
to sterilize equipment and media
Question: Where are you likely to find an autoclave?
Correct Answers
Question: The microbial growth curve has four phases
Answer:
lag, log, stationary, and death.
If a chemical could prevent microbial cell division, in which phase of growth
would it be most effective?: The log phase
Question: Considering the cell structure of mycoplasmas and other bacteria that stain
either Gram negative, Gram positive, or with acid-fast stains, which group
should you expect relies most on the presence of peptidoglycan for strength?-
Answer:
Gram-positive bacteria
Question: What is the function of tRNA during the process of translation?
Answer:
tRNA brings amino
acids to a growing chain of amino acids in ribosomes
Question: What is the difference between prokaryotic and eukaryotic ribosomes?
Answer:
-
Prokaryotic ribosomes consist of a 50S large and a 30S small subunit, while eukaryotic ribosomes
consist of a 60S
large and a 40S small subunit.
Question: Match the following descriptions of cellular structures with the type of cell
in which they are found.: Archaea: Hami, Protein cell wall
Bacteria: Peptidoglycan cell wall
Eukaryotes
Answer:
Organelles, 80S ribosome in cytosol
Question: Dr. Paul Ehrlich observed that the differential stain developed by Dr. Gram
suggested bacteria could be killed differentially by chemicals (Chapter 1). He
called these potential antibacterial agents "magic bullets".
Which among the following cell features of bacteria are potential targets for
,Dr. Ehrlich's "magic bullets" due to significant difference or absence from
humans? Choose all that apply.
Answer:
Ribosome and Cell wall
Question: Bacterial Structures... Label the structures of this bacterial cell. Drag the
appropriate labels to their respective locations.
Answer:
(From left to right)
DNA, Ribosome, Glycocalyx, Cell wall, Cytoplasmic Membrane
Question: The ____________ is a defining characteristic of bacteria which is not found in
eukaryotes and is therefore a good choice for chemotherapeutic agents.
View Available Hint(s)
Answer:
Peptidoglycan cell wall
Question: The cytosol of bacteria contain ____________ which has/have components
different from those of the functionally equivalent structure of eukaryotes.
View Available Hint(s)
Answer:
70S ribosomes
Question: What is meant by selective toxicity?
Answer:
Chemotherapeutic agents should act against the pathogen
and not the host.
Question: Why are chemotherapeutic agents that work on the peptidoglycan cell wall
of bacteria a good choice of drug?
Answer:
Humans and other animal hosts lack peptidoglycan cell walls.
Question: Why is polymyxin only used on the skin?
Answer:
It can also damage living human cell membranes,
but the drug is safely used on the skin, where the outer layers of cells are dead.
,Question: Quinolones and fluoroquinolones act against what bacterial target?
Answer:
DNA
gyrase
Question: Why is it difficult to find good chemotherapeutic agents against viruses?
Answer:
-
Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host
cell unaffected.
Question: Why do the beta-lactam drugs affect bacteria but NOT human cells?
Answer:
The
beta-lactam antibiotics act on bacterial cell walls; human cells do not have cell walls.
Question: A drug such as imipenem is chemically modified from penicillin. What are
non-natural drugs developed from natural drugs called?
Answer:
Semi-synthetics
Question: Typically, beta-lactam drugs affect the peptidoglycan layer on bacteria.
Why would beta-lactam drugs typically be considered more active against
Gram-positive bacteria and less so against Gram-negative bacteria?
Answer:
The cell walls
of Gram-positive bacteria have a thick peptidoglycan component.
Question: What effect does penicillin have on susceptible bacterial cells?
Answer:
Penicillin disrupts
cell wall synthesis.
Question: An antimicrobial that inhibits bacterial cell wall synthesis will result in which
of the following?
Answer:
Bacterial cells become more susceptible to osmotic pressure.
, Question: Classical pasteurization heats the fluid to about ___С for a time of about___-
Answer:
minutes
Question: Geogemma barossii is a hyperthermophilic archaeon that grows near hydrothermal vents in
the ocean at temperatures as high as 121С. What effect
would standard autoclaving have on this microbe?
Answer:
Nothing
Question: Boiling for ten minutes does not kill ___
Answer:
Endospores
Question: Heating a broth culture of microorganisms to 140C for three seconds would
___ the culture.
Answer:
Sterilize
Question: It has been determined that the temperature in an autoclave should reach
__________ for sterilization.
Answer:
121 degrees Celsius
Question: What role does pressure play in an autoclave?
Answer:
Pressure is applied to boiling water to
prevent heat from escaping as steam.
Question: How do scientists ensure that autoclaved materials were actually sterilized?
Answer:
They may place a sterility indicator with a special dye to detect the growth of endospores.
Question: What is the purpose of an autoclave?
Answer:
to sterilize equipment and media
Question: Where are you likely to find an autoclave?
