 | Cytokinesis in Animals | Cytokinesis in Plants |
|---|---|---|
| Definition | The division of the cytoplasm in an animal cell during cell division, typically following nuclear division (mitosis or meiosis). | The division of the cytoplasm in a plant cell during cell division, typically following nuclear division (mitosis or meiosis). |
| Mechanism | Forms a cleavage furrow that pinches the cell in the middle using a contractile ring made of actin and myosin filaments. | Forms a cell plate at the center of the cell that grows outward to meet the existing cell wall. |
| Structures Involved | Contractile ring made of actin and myosin filaments; plasma membrane. | Phragmoplast (a specialized structure containing microtubules); vesicles from Golgi apparatus that form the cell plate; existing cell wall. |
| Direction of Division | Constriction occurs from the outside in (centripetal). | Cell plate formation proceeds from the inside out (centrifugal). |
| Role of Microtubules | Microtubules help position the contractile ring at the cell equator but are not directly involved in the constriction process. | Microtubules form the phragmoplast, which guides vesicles to the forming cell plate. |
| Vesicle Involvement | Limited vesicle involvement; primarily relies on contractile proteins. | Extensive vesicle involvement; Golgi-derived vesicles carry cell wall materials to build the cell plate. |
| Final Structure Formed | Two separate daughter cells with new plasma membranes. | Two separate daughter cells with new plasma membranes and a new cell wall between them. |
| Timing | Usually occurs simultaneously with the later stages of mitosis/meiosis. | Usually begins during late anaphase or telophase and may continue after nuclear division is complete. |
| Flexibility in Division Plane | More flexible in determining the division plane; can change depending on cell type and developmental context. | Less flexible due to the presence of a rigid cell wall; division plane is typically determined during preprophase by the preprophase band. |
| Cell Wall Consideration | No cell wall to divide; only needs to separate the plasma membrane and cytoplasm. | Must create a new cell wall between daughter cells in addition to separating the plasma membrane and cytoplasm. |
| Preprophase Band | No preprophase band forms in animal cells. | A preprophase band of microtubules typically forms to mark the future division site. |
| Energy Requirements | Requires ATP for contraction of the actomyosin ring. | Requires ATP for vesicle transport and cell plate formation. |
| Effect of Cytochalasin B | Cytochalasin B (which disrupts actin filaments) prevents cytokinesis in animal cells. | Cytochalasin B has less effect on plant cytokinesis since it relies more on microtubules than actin filaments. |
| Evolutionary Adaptations | Adapted for cells that need to be mobile and lack rigid cell walls. | Adapted for cells with rigid cell walls that cannot be easily pinched inward. |
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