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What function does the plant cell wall serve in relation to neighboring plant cells?
What function does the plant cell wall serve in relation to neighboring plant cells?
What is produced during cytokinesis to separate daughter cells in plants?
What is produced during cytokinesis to separate daughter cells in plants?
What type of wall is formed first in young plant cells?
What type of wall is formed first in young plant cells?
Which substance is commonly added to plant cell walls to form the secondary wall?
Which substance is commonly added to plant cell walls to form the secondary wall?
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What lifestyle change did early plant cells adopt due to the development of rigid cell walls?
What lifestyle change did early plant cells adopt due to the development of rigid cell walls?
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Where do new plant cells generally originate from?
Where do new plant cells generally originate from?
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What is a characteristic of primary cell walls in plant cells?
What is a characteristic of primary cell walls in plant cells?
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How do the compositions of primary and secondary cell walls differ?
How do the compositions of primary and secondary cell walls differ?
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What function does lignin serve in secondary cell walls?
What function does lignin serve in secondary cell walls?
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What determines the direction of cell expansion in plants?
What determines the direction of cell expansion in plants?
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What is the primary characteristic of the primary cell wall?
What is the primary characteristic of the primary cell wall?
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Which component forms a supporting network in the cell walls of woody plants?
Which component forms a supporting network in the cell walls of woody plants?
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What role does turgor pressure play in plant cells?
What role does turgor pressure play in plant cells?
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What is the primary orientation of newly deposited microfibrils in elongating plant cells?
What is the primary orientation of newly deposited microfibrils in elongating plant cells?
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What role do microtubules play in the orientation of cellulose microfibrils?
What role do microtubules play in the orientation of cellulose microfibrils?
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What happens to cellulose deposition when cortical microtubules are disassembled?
What happens to cellulose deposition when cortical microtubules are disassembled?
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How are the cellulose-synthesizing rosettes organized in relation to the cell membrane?
How are the cellulose-synthesizing rosettes organized in relation to the cell membrane?
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What allows for a change in the direction of cell growth in plant cells?
What allows for a change in the direction of cell growth in plant cells?
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Which statement about the association between cortical microtubules and plasma membrane is true?
Which statement about the association between cortical microtubules and plasma membrane is true?
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What is the immediate consequence of treating plant tissue with a microtubule-depolymerizing drug?
What is the immediate consequence of treating plant tissue with a microtubule-depolymerizing drug?
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What kind of proteins are thought to hold cortical microtubules in place?
What kind of proteins are thought to hold cortical microtubules in place?
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What is required for a developmental switch in microfibril orientation?
What is required for a developmental switch in microfibril orientation?
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What do local foci of cortical actin filaments contribute to in plant cells?
What do local foci of cortical actin filaments contribute to in plant cells?
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What contributes to the unique features of a plant's lifestyle?
What contributes to the unique features of a plant's lifestyle?
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What initiates the cross-linking of cellulose microfibrils in the wall material?
What initiates the cross-linking of cellulose microfibrils in the wall material?
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What directs the movement of the cellulose synthase complexes in the plant cell membrane?
What directs the movement of the cellulose synthase complexes in the plant cell membrane?
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How is the complexity of plant cell wall shaping primarily achieved?
How is the complexity of plant cell wall shaping primarily achieved?
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What provides tensile strength to the primary cell wall of plants?
What provides tensile strength to the primary cell wall of plants?
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Which component of the plant cell wall is known for its waterproof properties?
Which component of the plant cell wall is known for its waterproof properties?
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What role does the plant cell wall primarily serve?
What role does the plant cell wall primarily serve?
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How do cellulose microfibrils achieve their tensile strength?
How do cellulose microfibrils achieve their tensile strength?
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What is the primary component embedded in the cellulose network of the primary cell wall?
What is the primary component embedded in the cellulose network of the primary cell wall?
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What is the maximum turgor pressure a plant cell can develop?
What is the maximum turgor pressure a plant cell can develop?
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What governs the composition and thickness of a plant cell wall?
What governs the composition and thickness of a plant cell wall?
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What happens to a plant cell's turgor pressure in a hypotonic environment?
What happens to a plant cell's turgor pressure in a hypotonic environment?
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What is the primary role of pectin in the primary cell wall?
What is the primary role of pectin in the primary cell wall?
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Which statement accurately describes cellulose molecules?
Which statement accurately describes cellulose molecules?
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What characterizes the lamellae arrangement of cellulose microfibrils?
What characterizes the lamellae arrangement of cellulose microfibrils?
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Which polysaccharide is most abundant in plant cell walls?
Which polysaccharide is most abundant in plant cell walls?
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What is the primary cause of the wilted appearance in dehydrated plants?
What is the primary cause of the wilted appearance in dehydrated plants?
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What distinguishes the middle lamella from primary and secondary cell walls?
What distinguishes the middle lamella from primary and secondary cell walls?
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What is the primary role of cross-linking glycans in plant cell walls?
What is the primary role of cross-linking glycans in plant cell walls?
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Which sugar is NOT mentioned as a component of cross-linking glycans' backbone?
Which sugar is NOT mentioned as a component of cross-linking glycans' backbone?
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What effect does adding Ca2+ to a solution of pectin molecules have?
What effect does adding Ca2+ to a solution of pectin molecules have?
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What role do proteins play in plant cell walls?
What role do proteins play in plant cell walls?
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What ultimately determines the final shape of a plant cell?
What ultimately determines the final shape of a plant cell?
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Which process is regulated by the separation of cells at the middle lamella?
Which process is regulated by the separation of cells at the middle lamella?
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What is the significance of cellulose microfibrils in plant cell walls?
What is the significance of cellulose microfibrils in plant cell walls?
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How many distinct CESA genes are needed for primary cell wall synthesis?
How many distinct CESA genes are needed for primary cell wall synthesis?
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What application of pectins is mentioned as a practical use?
What application of pectins is mentioned as a practical use?
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What happens to the orientation of cellulose microfibrils during cell expansion?
What happens to the orientation of cellulose microfibrils during cell expansion?
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What primarily drives the expansion of a plant cell's volume?
What primarily drives the expansion of a plant cell's volume?
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In which region are certain pectins particularly abundant?
In which region are certain pectins particularly abundant?
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What is the relationship between the structure of individual cellulose microfibrils and their functionality?
What is the relationship between the structure of individual cellulose microfibrils and their functionality?
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What type of enzyme complex spins cellulose into microfibrils on the cell surface?
What type of enzyme complex spins cellulose into microfibrils on the cell surface?
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Study Notes
Plant Cell Walls: Structure and Function
- Plant cells are enclosed by a rigid extracellular matrix, the cell wall. This wall, composed of cellulose, differs from animal extracellular matrices primarily in its lack of nitrogen-containing polymers.
- The plant cell wall's rigidity allows plants to maintain a stationary lifestyle, in contrast to animal cells.
Cell Wall Composition and Type
- Cell walls originate from dividing cells and are initially thin (primary cell wall), allowing for growth.
- Subseqently, cells may develop secondary cell walls by adding layers of matrix material, often with a different composition that enhances rigidity.
- Lignin, a phenolic polymer, commonly found in secondary walls, provides strength and water resistance.
- The principle of tension and compression, as used in other composite materials like fiberglass and concrete, underlies plant cell wall architecture.
- Cellulose microfibrils provide tensile strength.
- Pectic polysaccharides form a hydrated network that fills the gaps between microfibrils preventing compression.
- The middle lamella, rich in pectins, cements together adjacent plant cells.
Turgor Pressure and Cell Wall Strength
- Plant cells maintain internal pressure, turgor pressure, due to osmotic imbalances between the cell and its surroundings.
- Turgor pressure pushes outwards on the cell wall, driven by the intake of water.
- Turgor pressure is essential for plant cell growth, keeping tissues rigid.
- Cell wall strength is crucial for resisting this internal pressure, preventing bursting.
Cellulose Microfibrils and Cell Wall Architecture
- Cellulose molecules, long chains of linked glucose, form microfibrils.
- These microfibrils are aligned in lamellae, creating a complex plywood-like network within the wall, giving tensile strength.
- Cross-linking glycans firmly connect these microfibrils.
- Pectin polysaccharides form a separate, hydrated network within the wall to resist compression.
- Proteins in the wall, including enzymes and structural proteins like hydroxyproline, impact wall function and response to stress (damage/pathogens).
Microtubules and Cell Wall Orientation
- Cortical microtubules, organized just inside the plasma membrane, align with cellulose microfibril deposition in the cell wall.
- This alignment directs the direction of expansion. New cell wall materials are laid down internally, adding concentric layers.
- Microtubules act as guides to determine the cellulose microfibril alignment which, in turn, specifies the direction of cell expansion.
- Cell elongation is driven and guided by the direction of cellulose microfibrils.
- Modification of microtubule organization can lead to shifts in elongation patterns.
Cellulose Production and Deposition
- Cellulose synthase complexes embedded in the plasma membrane assemble cellulose chains from UDP-glucose into microfibrils.
- Microfibrils are then laid down in concentric lamellae, with the oldest layers on the exterior.
- The relative orientation of cellulose microfibrils deposited in successive layers correlates with cell shape.
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Description
Explore the essential components and functions of plant cell walls in this quiz. Learn about the differences between primary and secondary cell walls, including their composition and the role of lignin. Understand how these structures provide rigidity and support to plants, enabling their stationary lifestyle.
