Cytokinesis — Definition & Overview

What Is Cytokinesis?

This is the step in cell division where the cell actually, well, divides. It is different for animal and plant cells. At the end of this step, two identical daughter cells take the place of the original parent cell. The two new cells will enter interphase and prepare to divide themselves.

Division in Animal Cells

In animal cells, a cleavage furrow forms and divides the cell into two identical daughter cells. You can think of the cleavage furrow as wrapping a thread around a thin balloon. It pinches the balloon inwards and divided it into two parts. The left-hand side of the picture below is a good illustration of this.

Division in Plant Cells

Plant cells form something called a cell plate while they are dividing. This can be seen in the picture above on the right. The cell plate is the beginning of a new cell wall that separates the two identical daughter cells.

$$\color{#8925ae}{\text{Vocabulary Review:}}$$

$\color{#8925ae}{\text{Cell Cycle}}$ : The steps cells go through in order to grow and divide

$\color{#8925ae}{\text{Interphase}}$ : The longest part of the cell cycle where the cell grows and DNA is replicated to prepare for nuclear division

$\color{#8925ae}{\text{Nuclear Division}}$ : The process of dividing the nucleus

$\color{#8925ae}{\text{Mitosis}}$ : The process of dividing one nucleus into two identical nuclei. Mitosis occurs in all cells except for sex cells

$\color{#8925ae}{\text{Meiosis}}$ : The process of dividing one nucleus into four unique haploid cells. Meiosis only occurs in sex cells

$\color{#8925ae}{\text{Cytokinesis}}$ : The final step of cell division where the cytoplasm is divided to form daughter cells

$\color{#8925ae}{\text{Diploid Cell}}$ : Cell that contains two sets of chromosomes

$\color{#8925ae}{\text{Haploid Cell}}$ : Cell that contains only half the number of chromosomes. These are sperm and egg cells

Separating Cells

Cytokinesis is a vital part of the cell cycle. It happens as soon as mitosis (or meiosis) is done and is the physical separation of the cell components into two new cells.

The process is different for animal cells and plant cells.

Animal Cells

In animal cell cytokinesis, the plasma membrane is pulled inward, towards the center of the cell, by a contractile ring made of actin and myosin. As the membrane is pulled in, a cleavage furrow forms where the cell is being split. In many eukaryotic cells, a structure known as a contractile ring (formed by the mitotic spindle) helps with this process. Eventually, the mother cell is split into two daughter cells.

Plant Cells

Plant cells are much stiffer than animal cells. This is why they cannot be split in the same way. Instead, a cell plate forms between the two nuclei. The cell plate will turn into membranes and a cell wall will form between the membranes. This forms two daughter cells.

(Video) Mitosis: Splitting Up Is Complicated

by CrashCourse

The steps of mitosis are prophase, metaphase, anaphase, telophase, mitosis, and cytokinesis.

During this final stage of the cell cycle, the cell finally splits in two. The result is two identical daughter cells, each with a complete set of chromosomes.