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What is the main component of the bacterial cell wall?
What is the main component of the bacterial cell wall?
What is the function of bactoprenol in the cell wall structure?
What is the function of bactoprenol in the cell wall structure?
What is the term for the rigid structure of peptidoglycan specific only to prokaryotes?
What is the term for the rigid structure of peptidoglycan specific only to prokaryotes?
What is the location of the cell wall in a bacterial cell?
What is the location of the cell wall in a bacterial cell?
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What is the function of the capsule in a bacterial cell?
What is the function of the capsule in a bacterial cell?
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What is the term for the region of the bacterial cell where the DNA is found?
What is the term for the region of the bacterial cell where the DNA is found?
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What is the primary difference in cell wall structure between Gram-positive and Gram-negative bacteria?
What is the primary difference in cell wall structure between Gram-positive and Gram-negative bacteria?
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What is the function of teichoic acids in the cell wall of Gram-positive bacteria?
What is the function of teichoic acids in the cell wall of Gram-positive bacteria?
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What is the role of lipopolysaccharides in Gram-negative bacteria?
What is the role of lipopolysaccharides in Gram-negative bacteria?
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What is the function of the cell wall in protecting the cell from osmotic shock?
What is the function of the cell wall in protecting the cell from osmotic shock?
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What is the function of peptidoglycan in the cell wall of bacteria?
What is the function of peptidoglycan in the cell wall of bacteria?
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What is the function of the lipopolysaccharide layer in Gram-negative bacteria?
What is the function of the lipopolysaccharide layer in Gram-negative bacteria?
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What is the role of the cell wall in cell division?
What is the role of the cell wall in cell division?
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What is the function of the cell wall in Gram-positive bacteria?
What is the function of the cell wall in Gram-positive bacteria?
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What is a characteristic of bacteria that lack a cell wall?
What is a characteristic of bacteria that lack a cell wall?
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What is the main function of permeases in the cytoplasmic membrane?
What is the main function of permeases in the cytoplasmic membrane?
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What is the role of mesosomes in bacterial cells?
What is the role of mesosomes in bacterial cells?
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What is a function of the cytoplasmic membrane in relation to cell division?
What is a function of the cytoplasmic membrane in relation to cell division?
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What is the function of chemotactic systems in bacterial cells?
What is the function of chemotactic systems in bacterial cells?
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What is the function of cytochrome enzymes in the cytoplasmic membrane?
What is the function of cytochrome enzymes in the cytoplasmic membrane?
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What is a feature of the cytoplasmic membrane?
What is a feature of the cytoplasmic membrane?
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What is the function of exoenzymes in bacterial cells?
What is the function of exoenzymes in bacterial cells?
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Study Notes
Bacterial Cell Structure
- The structure of a bacterial cell can be divided into four main components: external structure, cell envelope, internal structures, and endospore.
External Structure
- The external structure consists of a capsule, flagella, and pili.
- A capsule is a protective layer that helps bacteria resist phagocytosis and desiccation.
- Flagella are responsible for bacterial movement and chemotaxis.
- Pili are responsible for bacterial conjugation and DNA transfer.
Cell Envelope
- The cell envelope consists of a cell wall and a cytoplasmic membrane.
- The cell wall is a rigid structure that provides support and maintains the cell's shape.
- The major component of the bacterial cell wall is peptidoglycan (murein).
- Peptidoglycan is a polymer of disaccharides (glycan) cross-linked by short chains of identical amino acids (peptides).
Cell Wall Structure
- The cell wall of Gram-positive bacteria is thick and contains many layers of peptidoglycan and teichoic acids.
- The cell wall of Gram-negative bacteria is relatively thin and consists of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins.
Functions of Cell Wall
- The cell wall determines the shape of the cell.
- It determines the staining reaction of the Gram stain.
- It plays an important role in cell division.
- It provides structural support and protects the cytoplasmic membrane.
- It provides osmotic protection and protects the cell from bursting in hypotonic solution.
- It protects the bacteria against the action of antibodies, antibiotics, and lysozyme.
Cell-Wall-Deficient Bacteria
- Some bacteria, such as Mycoplasma and L-form bacteria, lack a cell wall.
- These bacteria survive by living inside another host cell.
- They are not affected by antibiotic treatments that target cell wall synthesis.
Cytoplasmic Membrane
- The cytoplasmic membrane is a semi-permeable membrane that regulates the movement of molecules in and out of the cell.
- It is composed of proteins and phospholipids.
- It is osmotically sensitive and can be affected by changes in the concentration of solutes.
Functions of Cytoplasmic Membrane
- It maintains a constant environment within the cell by regulating the movement of molecules.
- It plays an important role in cell division.
- It contains cytochrome enzymes responsible for respiration and energy generation.
- It is involved in the excretion of hydrolytic exoenzymes that digest large food molecules.
- It is involved in the secretion of exotoxins.
- It contains chemotactic systems that attractants and repellents bind to specific receptors.
Mesosome
- Mesosomes are complex invaginations of the cytoplasmic membrane into the cytoplasm.
- They play a role in cell division.
- They increase the surface area of the cytoplasmic membrane, increasing the efficiency of permeability and active transport.
- They are the site for respiratory enzymes.
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Description
This quiz covers the components of bacterial cell structure, including external and internal components, and categorizes them according to essentiality.
