The key difference between cytokinesis and mitosis is that cytokinesis refers to the division of the parental cell cytoplasm into two parts to form two daughter cells while mitosis refers to the division of the parental nucleus into two genetically identical daughter nuclei in order to produce two daughter cells.
There are two types of cell divisions as mitosis and meiosis. Mitotic cell division results in two daughter cells that are genetically identical to the parent cell. During mitosis, several major events take place, including the duplication of the genome, its segregation, and the division of cellular contents. The mitotic cell cycle consists of two main phases: interphase and M phase. Interphase can be further divided into three main phases as G1 (gap phase 1), S (synthesis), and G2 (gap phase 2). Mitotic (M) phase of the cell cycle consists of mitosis and cytokinesis. Cytokinesis simply refers to the cytoplasmic division while the mitosis refers to the nuclear division.
CONTENTS
1. Overview and Key Difference
2. What is Cytokinesis
3. What is Mitosis
4. Similarities Between Cytokinesis and Mitosis
5. Side by Side Comparison – Cytokinesis vs Mitosis in Tabular Form
6. Summary
What is Cytokinesis?
Cytokinesis is the final process of cell division in which parental cytoplasm divides into two parts by separating cytoplasmic organelles and duplicated genomes in order to form two daughter cells. It usually begins in late anaphase and continues throughout telophase and ends sometime after the nuclear membrane reformation around each daughter nucleus. As the new nuclei are formed in the late anaphase, the cytoplasm constricts along the plane of the metaphase plate, forming a cleavage furrow in animal cells or forming a cell plate in plant cells.
Figure 01: Cytokinesis
In animal cells, the cleavage furrow formation is initiated by a ‘contractile ring’, which is made up of a ring of proteins including contractile assembles of filamentous protein actin and motor protein myosin II. The contractile ring surrounds the cell equator beneath the cell cortex and bisects the axis of chromosome segregation. It is done by contracting the filamentous protein ring to shrink and pull the membrane inward.
Unlike animal cells, plant cells have a rigid cell wall. Therefore, cytokinesis occurs differently in plants and animals. In plant cells, an expanding membrane partition called a cell plate forms to divide the cells. The cell plate grows outward and fuses with the plasma membrane to form two new daughter cells. Then cellulose is laid down on the new plasma membrane, forming the new two cell walls.
What is Mitosis?
Mitosis is a complex and highly regulated process that occurs exclusively in eukaryotes. It involves assembling the spindle, binding the chromosomes, and moving the sister chromatids apart. Also, this process is the most important step in the separation of the two daughter genomes. Moreover, it is possible to divide the sequence of events of mitosis into five phases: prophase, prometaphase, metaphase, anaphase, and telophase.
Figure 02: Mitosis
Mitosis takes about two hours to complete – from prophase to telophase. First, the mitotic apparatus is formed during prophase. During prometaphase, chromosomes attach to the spindle. In metaphase, chromosomes align at the cell equator and then in anaphase, chromatids separate from each other by splitting from the centromeres. During telophase, separated chromatids reach their respective poles. Finally, the reformation of nuclear envelopes occurs by forming daughter nuclei at two poles. Thus, this completes the nuclear division successfully.
What are the Similarities Between Cytokinesis and Mitosis?
- Cytokinesis and mitosis are two phases of mitotic cell division.
- Both processes are extremely important in order to produce new daughter cells.
- However, cytokinesis takes place after the mitosis.
- Also, both mitosis and cytokinesis ensure the constant chromosome numbers in new cells.
What is the Difference Between Cytokinesis and Mitosis?
Mitosis involves the division and duplication of the cell’s nucleus or separation of duplicated chromosomes whereas cytokinesis involves the division of the cytoplasm to form two distinct, new daughter cells. So, this is the key difference between cytokinesis and mitosis. Furthermore, mitosis has five stages: prophase, prometaphase, metaphase, anaphase, and telophase. But cytokinesis does not have such phases. The five stages of mitosis act together and separate duplicated chromosomes into two parts whereas cytokinesis divides a cell into two separate cells. Hence, this is a significant difference between cytokinesis and mitosis.
Moreover, mitosis takes place after interphase while cytokinesis takes place after mitosis. Therefore, this is also a difference between cytokinesis and mitosis. However, mitosis can occur without cytokinesis, forming single cells with multiple nuclei (Ex: certain fungi and slime moulds). Also, a further difference between cytokinesis and mitosis is the time taken for each process. That is; mitosis takes more time to complete than cytokinesis does.
Below info-graphic explains the difference between cytokinesis and mitosis comparatively.
Summary – Cytokinesis vs Mitosis
Cytokinesis and mitosis are two important events that occur in cell division. In summarizing the difference between cytokinesis and mitosis, cytokinesis separates the cytoplasmic organelles and the duplicated genome into two daughter cells while mitosis divides parental nucleus into two genetically identical daughter nuclei. Also, mitosis occurs after interphase while cytokinesis takes place after mitosis. Furthermore, mitosis takes place throughout a longer time period than cytokinesis. However, both processes are equally important in order to produce new cells in multicellular organisms.
Reference:
1. “Cytokinesis.” Wikipedia, Wikimedia Foundation, 19 Feb. 2019, Available here.
2. “Phases of Mitosis.” Khan Academy, Available here.
Image Courtesy:
1. “Telophase” By Kelvinsong – Own work (CC BY 3.0) via Commons Wikimedia Commons Wikimedia
2. “Mitosis Stages” By Ali Zifan – Own work; Used information from: Campbell Biology (10th Edition) by Jane B. Reece & Steven A. Wasserman.and Nature.com (CC BY-SA 4.0) via Commons Wikimedia