Cytokinesis: Definition, Animal vs Plant Cells and When It Happens

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-11-01

Cytokinesis is the physical process of cell division that splits the cytoplasm, organelles, and cell membrane into two daughter cells after the nucleus has divided. It is the final step of the cell cycle's mitotic phase, ensuring that each new cell receives its own complete set of cellular machinery. While mitosis divides the genetic material in the nucleus, cytokinesis divides the cell itself. This process is essential for growth, development, and tissue repair in all multicellular organisms.

Key Takeaways

• Cytokinesis is the division of the cytoplasm that follows nuclear division, producing two daughter cells with identical genetic material after mitosis.
• Animal cells use a contractile ring of actin and myosin to pinch the cell in half, forming a cleavage furrow.
• Plant cells build a new cell wall and membrane from the inside out, using a structure called a cell plate.
• Cytokinesis begins during late anaphase and is typically completed by the end of telophase.
• Failure of cytokinesis results in a single cell with two or more nuclei, a condition called multinucleation.

What Is Cytokinesis? A Direct Definition

Cytokinesis is the cytoplasmic division that follows mitosis, partitioning the cellular contents into two new daughter cells. The term comes from the Greek words "kytos" (cell) and "kinesis" (movement). It is a distinct process from karyokinesis, which is the division of the nucleus. The mitotic phase of the cell cycle includes both karyokinesis and cytokinesis, and together they complete cell division [1]. Without cytokinesis, a cell would end up with multiple nuclei but remain as one large cell.

The Timing of Cytokinesis in the Cell Cycle

Cytokinesis does not wait for mitosis to finish. In animal cells, the process begins during late anaphase, while the chromosomes are still moving toward opposite poles. The final separation of the two daughter cells, called abscission, is usually completed during or just after telophase.

The cell cycle has two major phases: interphase and the mitotic phase [1]. Interphase is when the cell grows and replicates its DNA. The mitotic phase includes mitosis (nuclear division) and cytokinesis (cytoplasmic division). The timing of cytokinesis relative to the other stages is shown below.

Cytokinesis in Animal Cells: The Cleavage Furrow

Animal cells divide by a process of pinching inward. The first visible sign is a shallow groove on the cell surface, called the cleavage furrow. This furrow forms at the cell equator, which is the plane where the chromosomes lined up during metaphase.

The furrow is created by a contractile ring made of actin filaments and the motor protein myosin-II [3]. These proteins assemble just beneath the plasma membrane at the equator. The myosin-II pulls on the actin filaments, causing the ring to constrict, much like pulling the drawstring of a bag. As the ring tightens, the cleavage furrow deepens, and the cell is gradually pinched into two halves [2].

The position of the furrow is controlled by signals from the mitotic spindle. During anaphase, the spindle sends a signal to the cell cortex that marks the equator. This ensures the furrow forms in the right place, so each daughter cell receives one complete set of chromosomes. The process of constriction continues until the two cells are connected only by a thin cytoplasmic bridge.

Abscission: The Final Cut

The last step of cytokinesis in animal cells is called abscission. At this point, the contractile ring has fully constricted, leaving a narrow tube of membrane between the two daughter cells. This tube contains a dense protein structure called the midbody, which is derived from the remnants of the mitotic spindle [2].

During abscission, the membrane at the midbody is pinched off and sealed. This requires the coordinated action of proteins that remodel the membrane and the cytoskeleton. The end result is two completely separate, independent cells. Abscission is a highly regulated step, and its failure can lead to cells that remain connected or that fuse back together.

Cytokinesis in Plant Cells: The Cell Plate

Plant cells face a unique challenge during cytokinesis. They have a rigid cell wall that surrounds the plasma membrane, so they cannot pinch inward like animal cells. Instead, they build a new cell wall from the inside out. For a review of the structural differences between these cell types, see our Animal vs Plant Cell comparison.

The process begins in late anaphase or telophase when a structure called the phragmoplast forms between the two daughter nuclei. The phragmoplast is a complex array of microtubules, actin filaments, and vesicles. These vesicles are derived from the Golgi apparatus and carry materials needed for the new cell wall [1]. The Golgi apparatus plays a central role in packaging these materials, as described in our Golgi Body guide.

The Golgi-derived vesicles are transported along the phragmoplast microtubules to the center of the cell. Here, they fuse together to form a flattened, membrane-bound sac called the cell plate. The cell plate grows outward from the center toward the edges of the cell. As it expands, it fuses with the existing plasma membrane and cell wall of the parent cell.

Once the cell plate has fused with the parent cell wall, it becomes the new cell wall that separates the two daughter cells. The membrane on either side of the plate becomes the new plasma membrane for each daughter cell. This process is complete by the end of telophase. The structure of the cell wall itself is key to understanding this process, and you can learn more in our Cell Wall guide.

Karyokinesis vs Cytokinesis: Two Distinct Processes

It is easy to confuse mitosis and cytokinesis, but they are separate events. Karyokinesis is the division of the nucleus, and it includes the stages of prophase, metaphase, anaphase, and telophase. Cytokinesis is the division of the cytoplasm, and it is a separate process that often runs in parallel with the later stages of mitosis [1]. To review the stages of nuclear division in order, see our Phases of Mitosis article.

The key differences between the two processes are listed in the table below.

The two processes are tightly coordinated, but they are not the same thing. A cell can undergo karyokinesis without cytokinesis. This happens naturally in some tissues, such as liver cells, which can be binucleate. It can also happen as a result of experimental manipulation or disease [1].

What Happens When Cytokinesis Fails?

When cytokinesis fails, the cell does not divide, but the nucleus has already divided. This results in a single cell with two nuclei, called a binucleate cell. If the failure happens repeatedly, the cell can become multinucleate, with many nuclei in one shared cytoplasm [1].

Cytokinesis failure can have serious consequences. It is a common feature of cancer cells, and it can contribute to the development of tumors. The resulting cells often have an abnormal number of chromosomes, a condition called aneuploidy. This genetic instability can drive the progression of cancer. In normal cells, cytokinesis is tightly regulated to prevent this from happening. The cell cycle checkpoints help ensure that division is completed correctly, as explained in our guide to Cell Cycle Checkpoints.

For a broader overview of how cells divide, including the differences between mitosis and meiosis, see our Mitosis vs Meiosis comparison. If you are new to cell biology, our Cell Biology 101 guide covers the fundamentals of cells, DNA, and genetics.

Frequently Asked Questions

What is the simple definition of cytokinesis?

Cytokinesis is the division of a cell's cytoplasm and its contents into two daughter cells. It is the final step of cell division, following the division of the nucleus. This process ensures that each new cell gets its own set of organelles, membranes, and other cytoplasmic components. It is the physical act of a single cell becoming two separate cells.

What is mitosis vs cytokinesis?

Mitosis is the division of the nucleus, which includes the separation of duplicated chromosomes. Cytokinesis is the division of the cytoplasm, which splits the entire cell. Mitosis produces two daughter nuclei, while cytokinesis produces two complete daughter cells. They are sequential and coordinated, but they are distinct processes. Mitosis is also called karyokinesis.

When does cytokinesis occur in the cell cycle?

Cytokinesis occurs during the mitotic phase of the cell cycle, which follows interphase. It begins during late anaphase of mitosis and is typically completed by the end of telophase. In animal cells, the cleavage furrow forms during anaphase. In plant cells, the cell plate begins to form during telophase. The process is complete when two separate daughter cells are formed.

How does cytokinesis occur in animal cells?

Animal cells divide by forming a cleavage furrow. A contractile ring made of actin and myosin-II filaments assembles beneath the plasma membrane at the cell equator. The myosin motor proteins pull the actin filaments, causing the ring to constrict. This pinches the cell inward, deepening the furrow until the cell is split into two. The final separation is completed by abscission at the midbody.

What is another name for cytokinesis?

Cytokinesis is sometimes called cytoplasmic division. The term "cytokinesis" is the standard scientific name. It is distinct from karyokinesis, which is the division of the nucleus. Together, karyokinesis and cytokinesis make up the complete process of cell division. All these terms describe the physical splitting of the cell's cytoplasm.

What happens if cytokinesis fails?

If cytokinesis fails, the cell does not split into two. The nucleus has already divided, so the result is a single cell with two or more nuclei, known as a binucleate or multinucleate cell. This can lead to an abnormal number of chromosomes, a condition called aneuploidy. Cytokinesis failure is often observed in cancer cells and can contribute to tumor progression and genetic instability.

References

1. Clark MA, Douglas M, Choi J (2018). 10.2 The Cell Cycle. Biology 2e, OpenStax.
2. Green RA, Paluch E, Oegema K (2012). Cytokinesis in Animal Cells. Annual Review of Cell and Developmental Biology 28:29-58.
3. Pollard TD (2010). Mechanics of cytokinesis in eukaryotes. Current Opinion in Cell Biology 22:50-56.