©FYNDLAY.
MCB4403 Final Exam Questions And
Answers 100% Verified.
How does the cellular structure of prokaryotes and eukaryotes differ? - Answers✔Prokaryotes
have fimbriae, pili, and flagella while eukaryotes have flagella and cilia
Prokaryotes have ____ ribosomes while eukaryotes have ______ ribosomes; what causes this
difference? - Answers✔Prokaryotes have 70S ribosomes while eukaryotes have 80S ribosomes;
Eukaryotes have 80S because they sediment faster than the more ancient prokaryotic 70S
How does the gram negative cell envelope differ from the gram positive cell envelope? -
Answers✔Gram negative = Have two phospholipid bilayers, and have
lipopolysaccharides (LPS)
Gram positive = Have teichoic acids and lipoteichoic acids, have a very thick layer of
peptidoglycan
What endotoxic characteristic is specific to gram negative cells? - Answers✔Lipid A
Selective vs differential media - Answers✔Selective media allow certain types of organisms to
grow, and inhibit the growth of other organisms. ... Differential media are used to differentiate
closely related organisms or groups of organisms.
What is most impacted by penicillin? - Answers✔Gram-positive bacteria
Characteristics of bacillus anthracis - Answers✔found in soil, forms endospores, aerobic, gram
positive
bacterial growth curve - Answers✔lag phase, log phase, stationary phase, death phase
temperature dependent growth curve - Answers✔temperature range determines growth and
survival rates
Hershey-Chase Experiment (the waring blender experiment) - Answers✔convinced scientific
community that DNA and not protein was the carrier of genes
-used bacterial virus T2 and grew it containing different media: sulfur (protein) and phosphorus
(DNA)
1
, ©FYNDLAY.
-proves that DNA (phosphorous) was carrier of genes because protein (sulfur) did not pass the
trait onto offspring, while phosphorous (DNA) did
What is transformation? - Answers✔uptake of DNA from environment; only competent cells can
uptake DNA; DNA must both enter the cell and integrate into the host genome (bacteria cannot
be transformed with DNA from unrelated species)
What is needed structurally for transformation of genetic material to occur? - Answers✔PILUS
is required to pull the donor cell close to the recipient; DNA must be in A SELF REPLICATING
VECTOR
Structures of viruses - Answers✔Very simple and consist of:
1) a protein coat (capsid)
- may be surrounded by a host-derived membrane (envelope)
2) a nucleic acid core
Viral shape is determined by what? - Answers✔viral shape is determined by its capsid
Viral capsid - Answers✔- outermost layer in non-enveloped viruses
- protect the nucleic acid core from environment
- made of subunits called capsomers
- capsomers spontaneously assemble into capsids
what are the three main shapes of capsomers? - Answers✔helical (tube), icosadehdral (3D sphere
with 20 triangular faces), and complex (alien)
viral envelope - Answers✔- much more common in animal than plant viruses
- Lipid bilayer is derived from the host's nuclear
or cytoplasmic membrane
- Envelope is susceptible to environmental
stress
You want to make homemade beer. Sadly, you do not own an autoclave and you're worried
about endospore contamination. Which process should you use for sterilization? -
Answers✔Tyndalization (= a sterilization method that kills all forms of microbial life, including
the spores)
pasteurization does not kill spores
Which of the following is true about yogurt production? - Answers✔Fermentation with pure
cultures of Lactobacillus bulgaricus and Streptococcus salivarius will produce yogurt
2
, ©FYNDLAY.
Which commercial biochemical compounds are produced by microbes? - Answers✔Vitamins,
amino acids, MSG (monosodium glutamate), insulin, reverse transcriptase
A human is infected with a protozoan. Which of the following treatments is most likely done? -
Answers✔Target synthesis of folic acid because humans don't synthesize this but protozoans do
Which of the following is NOT a way that antivirals inhibit viruses? - Answers✔antivirals
inhibit cell wall synthesis
Why is phage therapy not commonly used in the USA? - Answers✔The early success and
commercialization of antibiotics overshadowed it.
Which assay would allow you to determine whether bacteria are susceptible to an antibiotic? -
Answers✔A minimum inhibitory concentration (MIC) assay and a disk diffusion assay
Which of the following would NOT be a good target for a safe and effective bacterial antibiotic?
- Answers✔chitin biosynthesis and cellulose biosynthesis
Sulfa drugs were purified and used before antibiotics. Why are they rarely used today? -
Answers✔they have too many undesirable side effects and
bacterial resistance to them is widespread
What is the major contribution of Alexander Flemming? - Answers✔He was the first to isolate
penicillin from fungi
Why would an antibiotic that targets cell wall synthesis be safer for humans than one that targets
nucleic acids? - Answers✔Human cells do not have a cell wall, but bacterial cells do
What is septic shock and what causes it? - Answers✔- Septic shock is the last and most severe
stage of sepsis.
- Sepsis occurs when your immune system has an extreme reaction to an infection
- Bacterial infections are the most common cause of sepsis.
- The source of the infection can be anywhere in your body
exotoxin - Answers✔- Proteins or metabolites that are released from living bacteria - Mostly
produced by Gram-positive bacteria
bacterial metabolites - Answers✔Primary metabolites include amino acids, nucleotides, and
fermentation end products such as ethanol and organic acids, which are considered essential for
proper growth of microorganisms.
What makes something an infectious disease? - Answers✔- Infectious diseases are illnesses
caused by germs (such as bacteria, viruses, and fungi) that enter the body, multiply, and can
cause an infection
- A pathogen infection that leads to significant harm to the host is called an infectious disease
3
MCB4403 Final Exam Questions And
Answers 100% Verified.
How does the cellular structure of prokaryotes and eukaryotes differ? - Answers✔Prokaryotes
have fimbriae, pili, and flagella while eukaryotes have flagella and cilia
Prokaryotes have ____ ribosomes while eukaryotes have ______ ribosomes; what causes this
difference? - Answers✔Prokaryotes have 70S ribosomes while eukaryotes have 80S ribosomes;
Eukaryotes have 80S because they sediment faster than the more ancient prokaryotic 70S
How does the gram negative cell envelope differ from the gram positive cell envelope? -
Answers✔Gram negative = Have two phospholipid bilayers, and have
lipopolysaccharides (LPS)
Gram positive = Have teichoic acids and lipoteichoic acids, have a very thick layer of
peptidoglycan
What endotoxic characteristic is specific to gram negative cells? - Answers✔Lipid A
Selective vs differential media - Answers✔Selective media allow certain types of organisms to
grow, and inhibit the growth of other organisms. ... Differential media are used to differentiate
closely related organisms or groups of organisms.
What is most impacted by penicillin? - Answers✔Gram-positive bacteria
Characteristics of bacillus anthracis - Answers✔found in soil, forms endospores, aerobic, gram
positive
bacterial growth curve - Answers✔lag phase, log phase, stationary phase, death phase
temperature dependent growth curve - Answers✔temperature range determines growth and
survival rates
Hershey-Chase Experiment (the waring blender experiment) - Answers✔convinced scientific
community that DNA and not protein was the carrier of genes
-used bacterial virus T2 and grew it containing different media: sulfur (protein) and phosphorus
(DNA)
1
, ©FYNDLAY.
-proves that DNA (phosphorous) was carrier of genes because protein (sulfur) did not pass the
trait onto offspring, while phosphorous (DNA) did
What is transformation? - Answers✔uptake of DNA from environment; only competent cells can
uptake DNA; DNA must both enter the cell and integrate into the host genome (bacteria cannot
be transformed with DNA from unrelated species)
What is needed structurally for transformation of genetic material to occur? - Answers✔PILUS
is required to pull the donor cell close to the recipient; DNA must be in A SELF REPLICATING
VECTOR
Structures of viruses - Answers✔Very simple and consist of:
1) a protein coat (capsid)
- may be surrounded by a host-derived membrane (envelope)
2) a nucleic acid core
Viral shape is determined by what? - Answers✔viral shape is determined by its capsid
Viral capsid - Answers✔- outermost layer in non-enveloped viruses
- protect the nucleic acid core from environment
- made of subunits called capsomers
- capsomers spontaneously assemble into capsids
what are the three main shapes of capsomers? - Answers✔helical (tube), icosadehdral (3D sphere
with 20 triangular faces), and complex (alien)
viral envelope - Answers✔- much more common in animal than plant viruses
- Lipid bilayer is derived from the host's nuclear
or cytoplasmic membrane
- Envelope is susceptible to environmental
stress
You want to make homemade beer. Sadly, you do not own an autoclave and you're worried
about endospore contamination. Which process should you use for sterilization? -
Answers✔Tyndalization (= a sterilization method that kills all forms of microbial life, including
the spores)
pasteurization does not kill spores
Which of the following is true about yogurt production? - Answers✔Fermentation with pure
cultures of Lactobacillus bulgaricus and Streptococcus salivarius will produce yogurt
2
, ©FYNDLAY.
Which commercial biochemical compounds are produced by microbes? - Answers✔Vitamins,
amino acids, MSG (monosodium glutamate), insulin, reverse transcriptase
A human is infected with a protozoan. Which of the following treatments is most likely done? -
Answers✔Target synthesis of folic acid because humans don't synthesize this but protozoans do
Which of the following is NOT a way that antivirals inhibit viruses? - Answers✔antivirals
inhibit cell wall synthesis
Why is phage therapy not commonly used in the USA? - Answers✔The early success and
commercialization of antibiotics overshadowed it.
Which assay would allow you to determine whether bacteria are susceptible to an antibiotic? -
Answers✔A minimum inhibitory concentration (MIC) assay and a disk diffusion assay
Which of the following would NOT be a good target for a safe and effective bacterial antibiotic?
- Answers✔chitin biosynthesis and cellulose biosynthesis
Sulfa drugs were purified and used before antibiotics. Why are they rarely used today? -
Answers✔they have too many undesirable side effects and
bacterial resistance to them is widespread
What is the major contribution of Alexander Flemming? - Answers✔He was the first to isolate
penicillin from fungi
Why would an antibiotic that targets cell wall synthesis be safer for humans than one that targets
nucleic acids? - Answers✔Human cells do not have a cell wall, but bacterial cells do
What is septic shock and what causes it? - Answers✔- Septic shock is the last and most severe
stage of sepsis.
- Sepsis occurs when your immune system has an extreme reaction to an infection
- Bacterial infections are the most common cause of sepsis.
- The source of the infection can be anywhere in your body
exotoxin - Answers✔- Proteins or metabolites that are released from living bacteria - Mostly
produced by Gram-positive bacteria
bacterial metabolites - Answers✔Primary metabolites include amino acids, nucleotides, and
fermentation end products such as ethanol and organic acids, which are considered essential for
proper growth of microorganisms.
What makes something an infectious disease? - Answers✔- Infectious diseases are illnesses
caused by germs (such as bacteria, viruses, and fungi) that enter the body, multiply, and can
cause an infection
- A pathogen infection that leads to significant harm to the host is called an infectious disease
3
