CELS191 Lecture 8: Cell Walls and Plant Cell Shape

These flashcards cover key vocabulary and concepts related to plant cell walls and their functions.

Primary Cell Wall

The initial cell wall formed during cell growth, providing structural strength and support.

Secondary Cell Wall

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

Cellulose

The most abundant organic macromolecule on Earth, a glucose polymer that forms microfibrils in cell walls.

Turgor Pressure

The pressure exerted by the protoplast against the cell wall, maintaining cell rigidity.

Vacuole

An organelle in plant cells, typically a large, membrane-bound structure that stores water and solutes.

Hemicellulose

A heterogeneous group of polysaccharides that provides rigidity to the cell wall.

Pectin

Negatively charged polysaccharides that bind water and provide gel-like properties in the plant cell wall.

Extensin

A protein that cross-links polysaccharides in the cell wall, controlling extensibility.

Plasmodesmata

Intercellular connections that allow communication and transport of small molecules between plant cells.

Microfibrils

Highly ordered cellulose structures that provide strength to the plant cell wall.

Exocytosis

The process of transporting materials out of the cell, often involving the release of cell wall components.

Osmosis

The diffusion of water across a selectively permeable membrane, crucial for maintaining cell turgidity.

Cell Morphology

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

Lignin

A complex polymer providing strength and rigidity to secondary cell walls, responsible for water exclusion.

Energy Use

The annual production of plant cell walls is estimated to represent energy usage five times that of humans in 2022.

Functions of Cell Wall

Includes influencing cell morphology, providing structural support, and preventing excessive water uptake.

Cytoskeleton

A network of microtubules and filaments that provides structural support and maintains cellular organization.

Cell Wall Synthesis

Involves coordinated synthesis and delivery of cellulose microfibrils, polysaccharides, and proteins.

Wilting

A condition resulting from loss of turgor pressure when protoplasts do not push against the cell wall.

Cell Communication

Occurs through plasmodesmata, enabling the exchange of small molecules between neighboring plant cells.

Solute Concentration

High solute concentrations in vacuoles drive water uptake by osmosis, critical for maintaining cell turgidity.