Question

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.

In prokaryotes, constriction of a ring of________ cause infolding of the plasma membrane and cell wall during cell division (binary fission).
In plant cells, a network of________ functions in the formation of the cell plate.
In animal cells, a ring of________ constricts, creating a cleavage furrow.

Which two of these three have a similar mechanisms of cytokinesis or cell division?

a. animals and plants
b. animals and bacteria
c. plants and bacteria

Answer 1

Answer:

1. FtsZ tubulin homolog

2. actin and tubulin

3. actin and tubulin

4. b. animals and bacteria

Explanation:

1. In bacteria, the binary fission process takes place when the cytoskeletal structure of the bacteria are assembled to form the contractile ring in the centre of the cell. The contractile ring in bacteria is composed of the Z-protein which is a tubulin homolog.

2. Plants: the plants divide by the cell plate formation and not the contractile ring formation. This is mediated by the actin, tubulin and vesicle produced from the dictyosomes.

3. Animals: a contractile ring attached to the plasma membrane is formed which is composed of the F-actin and tubulin.

4. Since the bacteria and animal cytokinesis involves the formation of the contractile ring and thus the same mechanism of cytokinesis.