Plastos classification and structure

Plastids are cytoplasmic organs found in plant and algal cells.

Its shape and size vary by body type. In some algae, each cell has one or a few plastos of large size and characteristic shapes.

Already in other algae and plants in general, plastos are smaller and are present in large numbers per cell.

Plastids can be separated into two categories:

  • chromoplasts (from Greek chromos, color), which have pigments inside. The most common chromoplast in plants is the chloroplast, whose main component is chlorophyll, green in color. There are also red plastos, the erythroplasts (from Greek eritros, red), which develop, for example, into ripe tomato fruits.
  • leukoplasts (from Greek leukos, white), which do not contain pigments.

How do plastos appear

Plastos arise basically from cytoplasmic structures called proplasts, small spherical pockets, about 0.2 micrometers in diameter, bounded by two membranes. Inside the proplasts there are DNA, enzymes and ribosomes, but there are no tilacoids or chlorophyll. Proplasts are able to divide and are inherited from generation to generation, being transmitted from parents to children by gametes.