UF MCB3020 EXAM 2 Bacusmo UPDATED
Questions and CORRECT Answers
What is the most common mechanism for bacterial cell division? - CORRECT
ANSWER - Binary Fission
List the four steps of the mechanism above. - CORRECT ANSWER - 1. Elongation of the
cell
2. Replication of the chromosome
3. Separation of the chromosomes into the two parts of the cell
4. Formation of septum in the middle (Cytokinesis, or septation)
Define 'Origin of replication'. - CORRECT ANSWER - Where replication begins
How many Origins of replication do bacterial chromosomes have? - CORRECT
ANSWER - One
What is Cytokinesis? Include a brief overview of its four steps. - CORRECT ANSWER -
The division of the cell into two via formation of a cross wall between the two daughter cells.
Define the following terms and their role in cell division:
Penicillin-binding protein (PBP): - CORRECT ANSWER - Group of proteins that
hydrolyze bonds in existing peptidoglycan strands and link together new strands.
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM): - CORRECT ANSWER -
Major components of peptidoglycan that bind to a membrane protein called bactoprenol.
Autolysins: - CORRECT ANSWER - Degrade polypeptide where new units are to be
added, and the new NAM-NAG units can then be inserted into the peptidoglycan layer.
,What is crescentin? - CORRECT ANSWER - A homologue of eukaryotic intermediate
filaments
What are the other forms of asexual reproduction? Define each - CORRECT ANSWER --
Budding: Budding off daughter cells; seen in Listeria monocytogenes
-Baeocyte formation (multiple fission): Multiple rounds of cell division; seen in Cyanobacteria
-Spore formation: Form multinucleoid filaments that ultimately divide to produce spores with a
single nucleus.
Know the Bacterial Growth Curve - CORRECT ANSWER - lag,log,stationary,dead
List and define each phase of the above curve. - CORRECT ANSWER - -Lag Phase: No
net growth because, although the nutrients are abundant, the bacteria are adjusting to new
conditions.
-Log (Exponential) Phase: Nutrients are abundant, and bacteria divide at their highest rate.
-Stationary Phase: Number of viable microorganisms is stable because the nutrients level off and
waste products accumulate
-Death Phase: Nutrients are depleted, and levels of waste products and toxins are high, so the
number of viable microorganisms decreases
-Long-term Stationary Phase: Nutrients are depleted, and waves of genetic variants come and go
True or False: When nutrient levels are low, the limitation of microbial growth occurs as a result
of the saturation of transport proteins for nutrient uptake. - CORRECT ANSWER - False;
should be when levels are high
What is generation time (GT)? - CORRECT ANSWER - The time it takes the population
to double
What phase is it best to calculate GT? - CORRECT ANSWER - Log Phase (aka
Exponential Phase)
, True or False: Cells typically exist in aqueous conditions. - CORRECT ANSWER - true
Define hypertonic and hypotonic. - CORRECT ANSWER - Hypertonic: One solution has
higher concentration of solutes than another
Hypotonic: One solution has lower concentration of solutes than another
If a cell is in a hypertonic solution it will ____, while in a hypotonic solution it will ____. -
CORRECT ANSWER - Shrink; Burst
What are the three distinct cardinal growth temperatures for organisms? - CORRECT
ANSWER - 1. Minimum growth temperature: Lowest temperature at which an organism
can grow and survive
2. Maximum growth temperature: Highest temperature at which an organism can grow and
survive
3. Optimal growth temperature: Most suitable temperature for bacterial growth
Know the following microbial adaptations. Define each.
Halophiles - CORRECT ANSWER - Grow best in extremely salty environments
b. Xerophiles: - CORRECT ANSWER - Grow best in dry conditions
c. Psychrophiles: - CORRECT ANSWER - Grow between 0C and 20C - refrigeration
temperatures
d. Mesophiles: - CORRECT ANSWER - Grow between 20C and 45C
e. Thermophiles: - CORRECT ANSWER - Grow between 55C and 85C
f. Hyperthermophiles: - CORRECT ANSWER - Grow between 85C and 113C - usually
archaens
Questions and CORRECT Answers
What is the most common mechanism for bacterial cell division? - CORRECT
ANSWER - Binary Fission
List the four steps of the mechanism above. - CORRECT ANSWER - 1. Elongation of the
cell
2. Replication of the chromosome
3. Separation of the chromosomes into the two parts of the cell
4. Formation of septum in the middle (Cytokinesis, or septation)
Define 'Origin of replication'. - CORRECT ANSWER - Where replication begins
How many Origins of replication do bacterial chromosomes have? - CORRECT
ANSWER - One
What is Cytokinesis? Include a brief overview of its four steps. - CORRECT ANSWER -
The division of the cell into two via formation of a cross wall between the two daughter cells.
Define the following terms and their role in cell division:
Penicillin-binding protein (PBP): - CORRECT ANSWER - Group of proteins that
hydrolyze bonds in existing peptidoglycan strands and link together new strands.
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM): - CORRECT ANSWER -
Major components of peptidoglycan that bind to a membrane protein called bactoprenol.
Autolysins: - CORRECT ANSWER - Degrade polypeptide where new units are to be
added, and the new NAM-NAG units can then be inserted into the peptidoglycan layer.
,What is crescentin? - CORRECT ANSWER - A homologue of eukaryotic intermediate
filaments
What are the other forms of asexual reproduction? Define each - CORRECT ANSWER --
Budding: Budding off daughter cells; seen in Listeria monocytogenes
-Baeocyte formation (multiple fission): Multiple rounds of cell division; seen in Cyanobacteria
-Spore formation: Form multinucleoid filaments that ultimately divide to produce spores with a
single nucleus.
Know the Bacterial Growth Curve - CORRECT ANSWER - lag,log,stationary,dead
List and define each phase of the above curve. - CORRECT ANSWER - -Lag Phase: No
net growth because, although the nutrients are abundant, the bacteria are adjusting to new
conditions.
-Log (Exponential) Phase: Nutrients are abundant, and bacteria divide at their highest rate.
-Stationary Phase: Number of viable microorganisms is stable because the nutrients level off and
waste products accumulate
-Death Phase: Nutrients are depleted, and levels of waste products and toxins are high, so the
number of viable microorganisms decreases
-Long-term Stationary Phase: Nutrients are depleted, and waves of genetic variants come and go
True or False: When nutrient levels are low, the limitation of microbial growth occurs as a result
of the saturation of transport proteins for nutrient uptake. - CORRECT ANSWER - False;
should be when levels are high
What is generation time (GT)? - CORRECT ANSWER - The time it takes the population
to double
What phase is it best to calculate GT? - CORRECT ANSWER - Log Phase (aka
Exponential Phase)
, True or False: Cells typically exist in aqueous conditions. - CORRECT ANSWER - true
Define hypertonic and hypotonic. - CORRECT ANSWER - Hypertonic: One solution has
higher concentration of solutes than another
Hypotonic: One solution has lower concentration of solutes than another
If a cell is in a hypertonic solution it will ____, while in a hypotonic solution it will ____. -
CORRECT ANSWER - Shrink; Burst
What are the three distinct cardinal growth temperatures for organisms? - CORRECT
ANSWER - 1. Minimum growth temperature: Lowest temperature at which an organism
can grow and survive
2. Maximum growth temperature: Highest temperature at which an organism can grow and
survive
3. Optimal growth temperature: Most suitable temperature for bacterial growth
Know the following microbial adaptations. Define each.
Halophiles - CORRECT ANSWER - Grow best in extremely salty environments
b. Xerophiles: - CORRECT ANSWER - Grow best in dry conditions
c. Psychrophiles: - CORRECT ANSWER - Grow between 0C and 20C - refrigeration
temperatures
d. Mesophiles: - CORRECT ANSWER - Grow between 20C and 45C
e. Thermophiles: - CORRECT ANSWER - Grow between 55C and 85C
f. Hyperthermophiles: - CORRECT ANSWER - Grow between 85C and 113C - usually
archaens
