A lamella (plural, lamellae), in cell biology, is used to describe numerous plate or concentric layers or disc-like structures at both a intra-cellular(thylacoids, E.R., Mesosomes of blue green algae),cellular, tissue (Bone- Haversian system) and higher level.
An example of this being an extension of a thylakoid within a chloroplast, linking a thylakoid within one granum to one in another. They are the sites of photosystem I. Simply put, lamellae may be considered as a multiple parallel or concentric layers of of membranes as in chlorophyll.
Chloroplasts are characterized by a system of membranes embedded in a hydrophobic proteinaceous matrix, or stroma. The basic unit of the membrane system is a flattened single vesicle called the thylakoid; thylakoids stack into grana (sing, granum). All the thylakoids of a granum are connected with each other, and the grana are connected by intergranal lamellae.
It is placed between the two primary cell walls of two plant cells and made up of intracellular matrix. The lamella comprises a mixture of polygalacturons (D-galacturonic acid) and neutral carbohydrates. It is soluble in the pectinase enzyme.
A lamella, in cell biology, is also used to describe the leading edge of a motile cell, of which the lamellipodia is the most forward portion.
The lipid bilayer core of biological membranes, is also called lamellar phase. Thus, each bilayer of multilamellar liposomes and wall of a unilamellar liposome is also referred to as lamella.