Plant cell
Overview
The cells of plants are quite different from the cells of the other eukaryotic kingdom's organisms. Their distinctive features are:
- A large central vacuole (enclosed by a membrane, the tonoplast), which maintains the cell's turgor and controls movement of molecules between the cytosol and sap.
- A cell wall made up of cellulose and protein, and in many cases lignin, and deposited by the protoplast on the outside of the cell membrane. This contrasts with the cell walls of fungi, which are made of chitin, and prokaryotes, which are made of peptidoglycan.
- The plasmodesmata, linking pores in the cell wall that allow each plant cell to communicate with other adjacent cells. This is different from the network of hyphae used by fungi.
- Plastids, especially chloroplasts that contain chlorophyll, the pigment that gives plants their green color and allows them to perform photosynthesis.
- Plants lack centrioles that are present in animal cells.
Like other eukaryotic cells, plant cells typically also have a nucleus, containing most of the cell's DNA, and mitochondria, the 'power plants' of the cell. However, some parts of a living plant's tissue are selectively dead so they can serve the plant without consuming vital nutrients.
The three distinct types of plant cells are classified according to the structure of their cell walls and features of their protoplast. Plants will have a primary cell wall and sometimes a secondary wall as well. The protoplast These two major parts are what determines the function of each individual plant cell.
Plant cells have the ability to go through photosynthesis as well as respiration.
Types of plant cells
- Parenchyma ~ Thin primary walls, may not have a secondary wall. Can develop into more specialized plant tissues.
- Collenchyma ~ Unevenly thickened primary walls, grouped together to support growing parts of the plant.
- Sclerenchyma ~ Thick secondary walls, used to support non-growing parts of the plant.
These three major classes of cells can then differentiate to form the tissue structures of roots, stems, and leaves. All plants have these types of tissues and they have similar locations within all species of plants. However, the amount of these tissues will vary for different plant species.
Types of plant tissue systems
- Dermal ~ Surface cells with distinct characteristics for their location on the plant
- Vascular tissue ~ Responsible for transport of materials throughout the plant
- Ground ~ Performs photosynthesis, starch storage and structural support