Nearly all plant cells and many bacteria are surrounded by a cell wall. However, the roles these walls play in cell division differ dramatically. In plants, the wall is sufficiently rigid so that in most cells, constriction of a ring of proteins could not cause the wall to fold in and eventually pinch off. Rather, a new plant cell wall is produced between the daughter cells by the formation of a cell plate, which eventually joins with the existing cell wall. In contrast, in bacteria, the cell wall is sufficiently flexible to fold in during constriction of the FtsZ protein ring.
Bacteria lack the distinct microfilaments and microtubules that dominate the cytoskeletons of plant and animal cells. However, bacteria contain proteins that are similar to actin (the building block of microfilaments) and tubulin (the building block of microtubules). The tubulin-like proteins in bacteria function in the formation of two daughter cells through binary fission.
(A) In prokaryotes, constriction of a ring of (microtubules/ microfilaments/ tubulin-like proteins) cause infolding of the plasma membrane and cell wall during cell division (binary fission).
(B) In plant cells, a network of (microtubules/ microfilaments/tubulin-like proteins) functions in the formation of the cell plate.
(C) In animal cells, a ring of (microtubules/ microfilaments/tubulin-like proteins) constricts, creating a cleavage furrow.