CELS191 Lecture 8: Cell Walls & Their Role in Regulating Plant Cell Shape

These flashcards cover the key concepts related to the structure and function of plant cell walls, their role in regulating cell shape, and additional related topics covered in the lecture.

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Primary Plant Cell Wall

A cell wall that provides structural strength to plant cells, made up of cellulose microfibrils linked by hemicelluloses and pectin.

Cellulose

The most abundant organic macromolecule on Earth, made of glucose polymers, crucial for cell wall structure.

Vacuole

A membrane-bound organelle in plant cells that holds materials and maintains turgor pressure.

Plasmodesmata

Intercellular connections allowing communication and transport between plant cells.

Extensin

A type of protein that helps crosslink polysaccharides in the cell wall, providing extra strength.

Turgor Pressure

The pressure exerted by the fluid in a vacuole against the cell wall, maintaining cell rigidity.

Hemicellulose

A heterogeneous group of polysaccharides that contribute to the structural integrity of the plant cell wall.

Pectin

A branched polysaccharide that has gel-like properties and helps bind water in the plant cell wall.

Secondary Cell Wall

A thicker, stronger wall produced after cell growth has stopped, providing more structural support.

Lignin

A complex polymer that gives rigidity to the secondary cell wall and helps exclude water.

Osmosis

The diffusion of water across a selectively permeable membrane from a region of low solute to high solute concentration.

Microfibrils

Highly organized structures formed from cellulose that enhance the strength of cell walls.

Cell Wall Functions

Influences cell morphology, provides structural support, and prevents excessive water uptake.

Cell Morphology

The study of the structure and shape of cells, influenced by the orientation of cellulose microfibrils.

Water Uptake

The process by which plant cells absorb water, important for maintaining turgor pressure.

Exocytosis

The process by which materials are transported out of a cell or delivered to the cell surface.

Cytoskeleton

A network of fibers that provides structural support and maintains the position of organelles within the cell.

Cell Wall Components

Includes cellulose, hemicellulose, pectin, and extensin.

Microtubules

Cytoskeletal components that play a role in maintaining the position of organelles and providing structural support.

Crystalline Phase

The phase of cellulose microfibrils where they are highly ordered.

Matrix Phase

The non-crystalline part of the cell wall containing hemicellulose and pectin.

Cell Wall Synthesis

The coordinated process that involves the synthesis and delivery of cellulose, hemicellulose, and extensins.

Cell Shape Regulation

The process by which the plant cell wall influences the shape and expansion of plant cells.

Intercellular Communication

The process by which cells communicate with each other, often facilitated by structures like plasmodesmata.

Plant Cell Features

Characteristics that distinguish plant cells from animal cells, including cell walls and chloroplasts.

Role of Vacuole

To store nutrients and waste products, and to regulate cell turgor.

Cellulose Production

The process involving cellulose synthase rosettes that produce cellulose at the plasma membrane.

Turgidity

The state of being swollen or firm due to high water content in plant cells.

Wilting

Occurs when plant cells lose turgor pressure due to water loss.

Rigid Structure

A structure that is firm and maintains shape, influenced by turgor pressure and cell wall integrity.

Hypotonic Solution

A solution with a lower concentration of solutes compared to another solution, causing cells to swell.

Isotonic Solution

A solution with equal concentrations of solutes, causing no net movement of water in or out of cells.

Hypertonic Solution

A solution with a higher concentration of solutes compared to another solution, causing cells to shrink.

Cell Wall Layers

Different layers within the secondary cell wall that have varied orientations of microfibrils.

Plant Protein

Proteins that are involved in various functions including structural support and metabolic processes.

Cytoplasmic Streaming

The movement of cytoplasm within plant cells, facilitating the distribution of nutrients and organelles.

Cell Wall Rigidity

The strength and firmness of the cell wall that helps maintain the structure of plant cells.

Selectively Permeable Membrane

A type of membrane that allows certain substances to pass while restricting others.

Fungal Infection Response

The process by which plant cells respond to fungal threats, often by producing fungicides.

Cellulose Synthase

Enzyme complexes that synthesize cellulose at the plasma membrane.

Polysaccharide Types

Refers to the different forms of long carbohydrate molecules, such as pectin and hemicellulose.

Single Membrane Organelle

A type of organelle, like the vacuole, that is surrounded by a single lipid membrane.

Pressure Exerted by Cell Wall

The counteracting force from the cell wall that limits the expansion of plant cell volume.

Desmotubule

A structure within plasmodesmata that connects the endoplasmic reticulum of neighboring cells.

Rough Endoplasmic Reticulum (rER)

An organelle involved in the synthesis of proteins that are often glycosylated in the Golgi apparatus.

Family of Extensins

Proteins involved in cell wall structure that mediate cross-linking.

Plant Cells Communication

The interaction and exchange of materials between plant cells through plasmodesmata.

Structural Support in Plants

Refers to the function of cell walls and vacuoles in maintaining the integrity of plant structure.

Cell Wall Composition Changes

Variations in the composition of primary and secondary cell walls, such as cellulose and lignin content.

Evapotranspiration Impact

The effect of water loss from plants on cellular turgor and structure.

Heartwood Structure

The central core of a tree trunk, made largely of a thick secondary wall with lignin.

Vacuole Membrane

The single membrane that encloses the vacuole and regulates the movement of substances.

Root Cell Functionality

Refers to the way root cells interact with soil and water, influencing overall plant health.

Plant Cell Types

Refers to the various types of cells in plants, each specialized for different functions.

Macromolecule Abundance

Refers to the prevalence of certain organic macromolecules, like cellulose and lignin, in biological systems.

Glucose Polymers

Long chains of glucose molecules that make up cellulose.

Cell Structure Comparison

Examining differences and similarities in the structure of plant versus animal cells.

Protoplast

The living part of a plant cell, excluding the cell wall.

Cell Wall Mechanical Properties

Refers to the physical characteristics of cell walls that determine their strength and flexibility.

Microtubule Functionality

The role of microtubules in maintaining the cell’s structure and facilitating transport.

Cross-linking of Polysaccharides

The connection between different carbohydrates that provides strength to the cell wall.

Cotton Fiber Structure

An example of tightly packed cellulose fibers used commercially for textile production.

Cell Communication Mechanisms

The processes and structures that facilitate communication between plant cells.

Abundant Organic Macromolecules

Refers to cellulose and lignin, which are critical for structural integrity in plants.

Synthesis of Cell Wall Components

The biosynthetic pathways involved in producing cellulose, hemicellulose, and pectin.

Coordination of Synthesis

The integrated processes that ensure efficient production and assembly of cell wall materials.

Drought Stress Impact

The physiological effects observed in plant cells when subjected to reduced water availability.