3- Plant Cells and Simple Tissue Types

Plastids

Double-membraned organelles in plant cells that perform specific functions, such as photosynthesis (chloroplasts), pigment storage (chromoplasts), and carbohydrate storage (leucoplasts).

Vacuoles

Membrane-bound structures in plant cells that store water, sugars, salts, crystals, and pigments, and can account for up to 90% of the cell volume.

Primary Wall

The first cell wall formed at cell division in all plant cells, composed of cellulose and expands as the internal components of the cell expand.

Secondary Wall

A rigid cell wall composed of lignin and cellulose that forms in some plant cells after the primary wall, providing additional support and strength.

Plasmodesmata

Cytoplasmic connections between living plant cells that allow for selective molecule transport, usually formed at cell division.

Pits

Thinnings in the cell wall, usually between dead cells, that form at the location of plasmodesmata and allow for unregulated transport.

Middle Lamella

The material between plant cells, composed of pectin, that acts as a glue-like substance to hold the cells together.

Parenchyma

A type of simple tissue in plants that is usually living at maturity, has thin primary cell walls, and can be found all over the plant, functioning in storage and sometimes photosynthesis.

Collenchyma

A type of simple tissue in plants that is living at maturity, has unevenly thickened primary cell walls, and provides structured support, sometimes also involved in photosynthesis.

Sclerenchyma

A type of simple tissue in plants that is usually dead at maturity, has both primary and secondary cell walls, and functions in support and protection. It includes fibers and sclereids, with fibers being elongated and tapered, and sclereids being isodiametric or branched.