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Questions and Answers
What is the total number of cells after 12 generations if starting with 10 cells?
What is the total number of cells after 12 generations if starting with 10 cells?
The size of bacteria at birth does not influence its size at cell division.
The size of bacteria at birth does not influence its size at cell division.
False
What principle describes how cells add a fixed volume before division?
What principle describes how cells add a fixed volume before division?
Adder Principal
The bacterial cell cycle consists of three stages: B, C, and _____.
The bacterial cell cycle consists of three stages: B, C, and _____.
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Match the following components with their functions:
Match the following components with their functions:
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Which type of bacterial cell wall is characterized by the presence of mycolic acid?
Which type of bacterial cell wall is characterized by the presence of mycolic acid?
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All bacteria possess a cell wall.
All bacteria possess a cell wall.
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Name one type of bacteria that has an acid-fast cell wall.
Name one type of bacteria that has an acid-fast cell wall.
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Mycoplasmas are unique because they lack __________.
Mycoplasmas are unique because they lack __________.
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Match the following characteristics with the type of bacteria:
Match the following characteristics with the type of bacteria:
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What component is absent in the cell walls of archaea compared to typical bacteria?
What component is absent in the cell walls of archaea compared to typical bacteria?
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The outer membrane of gram-negative bacteria contains ________ that can play a role in permeability.
The outer membrane of gram-negative bacteria contains ________ that can play a role in permeability.
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What is the primary function of metachromatic granules in bacterial cells?
What is the primary function of metachromatic granules in bacterial cells?
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Endospores are highly susceptible to heat and chemicals.
Endospores are highly susceptible to heat and chemicals.
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What is the term used for the process of endospore formation?
What is the term used for the process of endospore formation?
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The equation for calculating the number of cells in a bacterial population is Nt = N0 x 2^____.
The equation for calculating the number of cells in a bacterial population is Nt = N0 x 2^____.
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Match the following bacterial structures with their functions:
Match the following bacterial structures with their functions:
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Which of the following best describes binary fission in prokaryotic cells?
Which of the following best describes binary fission in prokaryotic cells?
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Gas vacuoles are involved in nutrient storage in bacterial cells.
Gas vacuoles are involved in nutrient storage in bacterial cells.
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What is the process called when endospores return to the vegetative state?
What is the process called when endospores return to the vegetative state?
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The generation time of bacteria varies among different ______.
The generation time of bacteria varies among different ______.
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What is the main consequence of exponential bacterial growth?
What is the main consequence of exponential bacterial growth?
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Study Notes
Bacterial Cell Walls
- Bacterial cell walls consist of peptidoglycan, with structures including lipid A, core polysaccharide, and an O polysaccharide.
- The outer membrane contains porin proteins and lipoproteins, contributing to the cell wall integrity.
Atypical Cell Walls
- Acid-fast cell walls resemble gram-positive structures, featuring mycolic acid, found in Mycobacterium and Nocardia.
- Mycoplasmas lack cell walls entirely, having sterols in their plasma membrane.
- Archaea can either be wall-less or have walls made of pseudomurein, which do not contain N-acetylmuramic acid (NAM) or D-amino acids.
Prokaryotic Cell Structure
- Prokaryotic cells display various internal structures, including 70S ribosomes, plasmids, and inclusions for storage of energy reserves (lipid granules, polysaccharide granules, etc.).
- Endospores, formed through sporulation, are highly resilient resting cells capable of surviving extreme conditions, found in genera Bacillus and Clostridium.
Bacterial Growth
- Bacterial growth is commonly measured through various methodologies such as volume, size, and cell number, with a focus on the number of cells.
- Prokaryotic cells undergo binary fission, leading to exponential growth where population doubles with each division.
Generation Time
- The generation or doubling time varies by species and is crucial for understanding bacterial population dynamics.
- The growth equation (Nt = N0 x 2^n) calculates the number of cells after n divisions, with Nt representing the final cell count, N0 the original cell count, and n the number of divisions.
Cell Division Triggers
- Cell division occurs at critical sizes in a mechanism tied to size homeostasis; both timer and size theories explain cell division regulation.
- The “Adder Principle” states that cells add a fixed volume before division, ensuring consistent sizes across populations.
Prokaryotic Cell Cycle
- The prokaryotic cell cycle includes three stages: B (birth), C (chromosome replication), and D (completion of division).
- The divisome is a complex involving Fts proteins that coordinate the processes of cell division and chromosome replication.
FtsZ Ring
- The FtsZ protein forms a ring at the division site, regulated by carbon availability and peptidoglycan precursor levels (UDP-glucose).
Importance of Peptidoglycan
- Peptidoglycan plays a critical role in maintaining bacterial cell structure and integrity, providing resistance to osmotic pressure and determining cell shape.
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Description
This quiz focuses on the chapter about growth in microbiology, particularly examining bacterial cell walls and their structural components. It covers key concepts such as lipopolysaccharides and their parts, including core polysaccharides and lipid A. Test your knowledge on these vital topics in microbial structure and growth.
