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Questions and Answers
What results when a single bacterium reproduces?
What results when a single bacterium reproduces?
Two genetically identical daughter cells
If you begin with six cells, how many cells would you have after three rounds of division?
If you begin with six cells, how many cells would you have after three rounds of division?
forty-eight
Which of the following is not a step in bacterial cell division? (Select all that apply)
Which of the following is not a step in bacterial cell division? (Select all that apply)
Which step of binary fission is the reason for genetically identical daughter cells?
Which step of binary fission is the reason for genetically identical daughter cells?
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What enables the copied chromosomes to separate during binary fission?
What enables the copied chromosomes to separate during binary fission?
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How long does it take for the daughter cells to initiate or start the next round of replication?
How long does it take for the daughter cells to initiate or start the next round of replication?
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Put the following steps of bacterial replication in the correct order, starting from a parent cell: ______.
Put the following steps of bacterial replication in the correct order, starting from a parent cell: ______.
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What would happen if the septum did not form during binary fission?
What would happen if the septum did not form during binary fission?
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Starting with three cells, how many cells would result from three rounds of replication?
Starting with three cells, how many cells would result from three rounds of replication?
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In the figure, which line best depicts a facultative anaerobe in the absence of O2?
In the figure, which line best depicts a facultative anaerobe in the absence of O2?
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In the figure, which line best depicts a psychrotroph incubated at 0°C?
In the figure, which line best depicts a psychrotroph incubated at 0°C?
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Which of the following elements is NOT correctly matched with its cellular function? (Select all that apply)
Which of the following elements is NOT correctly matched with its cellular function? (Select all that apply)
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Salts and sugars work to preserve foods by creating a
Salts and sugars work to preserve foods by creating a
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The term aerotolerant anaerobe refers to an organism that
The term aerotolerant anaerobe refers to an organism that
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Most bacteria grow at pH
Most bacteria grow at pH
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Which of the following pairs of microbe classification terms and optimal growth temperatures is mismatched? (Select all that apply)
Which of the following pairs of microbe classification terms and optimal growth temperatures is mismatched? (Select all that apply)
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What does facultative halophile refer to?
What does facultative halophile refer to?
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Why do all cells need nitrogen?
Why do all cells need nitrogen?
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Most pathogenic bacteria are thermophiles.
Most pathogenic bacteria are thermophiles.
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Patients with indwelling catheters are susceptible to infections because
Patients with indwelling catheters are susceptible to infections because
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The majority of hospital-acquired infections are related to
The majority of hospital-acquired infections are related to
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Microbes in biofilms are less resistant to antimicrobials than are independent organisms.
Microbes in biofilms are less resistant to antimicrobials than are independent organisms.
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It is estimated that nearly ______ % of all infections are caused by biofilms.
It is estimated that nearly ______ % of all infections are caused by biofilms.
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Antimicrobials can be applied to the surface of catheters and IV tubing to prevent _______ _________.
Antimicrobials can be applied to the surface of catheters and IV tubing to prevent _______ _________.
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The biosafety level (BSL) for most introductory microbiology laboratories is
The biosafety level (BSL) for most introductory microbiology laboratories is
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A culture medium consisting of agar, peptone, and beef heart is a
A culture medium consisting of agar, peptone, and beef heart is a
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For which of the following types of microbes would a microbiologist employ living host cells to support their growth?
For which of the following types of microbes would a microbiologist employ living host cells to support their growth?
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Study Notes
Bacterial Cell Division
- A single bacterium reproduces by creating two genetically identical daughter cells.
- Starting with six cells, after three rounds of division, there will be forty-eight cells.
- Key steps in bacterial cell division include replication of genetic material, cell elongation, septum formation, and separation of daughter cells. The disappearance of the nuclear envelope is not involved.
- The replication of the bacterial chromosome ensures that daughter cells are genetically identical.
- Chromosomes separate during binary fission because they are attached to different cell membrane areas which elongate.
Initiation of Division
- Daughter cells are ready to initiate the next round of replication immediately after the previous round if conditions are favorable.
- The correct order of bacterial replication is: chromosome replication, cell elongation, septum formation, and separation of daughter cells.
Consequences of Faulty Division
- If the septum does not form during binary fission, the parent cell will not have two chromosome copies.
- Starting with three cells, three rounds of replication would yield twenty-four cells.
Microbial Growth and Environmental Factors
- A hypertonic environment is created by salts and sugars, helping to preserve foods.
- Aerotolerant anaerobes do not use oxygen but can tolerate its presence.
- The majority of bacteria prefer a neutral pH of 7 for optimal growth.
Microbial Classification
- Thermophiles are incorrectly matched with growth at 37°C; they thrive at higher temperatures.
- S. aureus can be classified as a facultative halophile, indicating its tolerance to high salt concentrations.
Nutritional Requirements
- Cells require nitrogen for synthesizing amino acids, proteins, and nucleic acids.
- Most pathogenic bacteria are not thermophiles, contrary to common assumptions.
Infections and Biofilms
- Indwelling catheters pose a risk for infections due to biofilm development on their surfaces.
- Hospital-acquired infections are primarily associated with biofilms; approximately 70% of all infections are attributed to these structures.
- Microbes in biofilms are more resistant to antimicrobials than independent organisms, challenging treatment efforts.
Safety and Media in Microbiology
- Most introductory microbiology labs operate at a biosafety level of BSL-1, indicating the lowest risk level.
- A culture medium composed of agar, peptone, and beef heart is classified as a complex medium.
- Obligate intracellular organisms, such as chlamydias, rickettsias, and viruses, require living host cells for cultivation.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the key concepts of bacterial cell reproduction and division with these flashcards. Ideal for students tackling Assignment 6 in Microbiology. Challenge yourself to answer questions about cell division processes and outcomes.
