Which is longer metaphase or prophase

Cytokinesis In animal cells, cytokinesis results when a fiber ring composed of a protein called actin around the center of the cell contracts pinching the cell into two daughter cells, each with one nucleus.

In plant cells, the rigid wall requires that a cell plate be synthesized between the two daughter cells. Mitosis animation k OR. Mitosis animation. Mitosis is nuclear division plus cytokinesis, and produces two identical daughter cells during prophase, prometaphase, metaphase, anaphase, and telophase. Interphase is often included in discussions of mitosis, but interphase is technically not part of mitosis, but rather encompasses stages G1, S, and G2 of the cell cycle.

Chromatin in the nucleus begins to condense and becomes visible in the light microscope as chromosomes. The nuclear membrane dissolves, marking the beginning of prometaphase.

The word "mitosis" means "threads," and it refers to the threadlike appearance of chromosomes as the cell prepares to divide. Early microscopists were the first to observe these structures, and they also noted the appearance of a specialized network of microtubules during mitosis. These tubules, collectively known as the spindle, extend from structures called centrosomes — with one centrosome located at each of the opposite ends, or poles, of a cell.

As mitosis progresses, the microtubules attach to the chromosomes, which have already duplicated their DNA and aligned across the center of the cell. The spindle tubules then shorten and move toward the poles of the cell. As they move, they pull the one copy of each chromosome with them to opposite poles of the cell. This process ensures that each daughter cell will contain one exact copy of the parent cell DNA. Mitosis consists of five morphologically distinct phases: prophase, prometaphase, metaphase, anaphase, and telophase.

Each phase involves characteristic steps in the process of chromosome alignment and separation. Once mitosis is complete, the entire cell divides in two by way of the process called cytokinesis Figure 1.

Walther Flemming: pioneer of mitosis research. Nature Reviews Molecular Cell Biology 2, 72 All rights reserved. Prophase is the first stage in mitosis, occurring after the conclusion of the G 2 portion of interphase.

During prophase, the parent cell chromosomes — which were duplicated during S phase — condense and become thousands of times more compact than they were during interphase. Because each duplicated chromosome consists of two identical sister chromatids joined at a point called the centromere , these structures now appear as X-shaped bodies when viewed under a microscope. Several DNA binding proteins catalyze the condensation process, including cohesin and condensin.

Cohesin forms rings that hold the sister chromatids together, whereas condensin forms rings that coil the chromosomes into highly compact forms. The mitotic spindle also begins to develop during prophase. As the cell's two centrosomes move toward opposite poles, microtubules gradually assemble between them, forming the network that will later pull the duplicated chromosomes apart.

When prophase is complete, the cell enters prometaphase — the second stage of mitosis. During prometaphase, phosphorylation of nuclear lamins by M-CDK causes the nuclear membrane to break down into numerous small vesicles.

As a result, the spindle microtubules now have direct access to the genetic material of the cell. As prometaphase ends and metaphase begins, the chromosomes align along the cell equator. The cell cycle consists of interphase and the mitotic phase. During interphase, the cell grows and the nuclear DNA is duplicated.

Interphase is followed by the mitotic phase. During the mitotic phase, the duplicated chromosomes are segregated and distributed into daughter nuclei. The cytoplasm is usually divided as well, resulting in two daughter cells.

This video reviews all the steps of mitosis; seeing it all together is a great review at this stage. Answer the question s below to see how well you understand the topics covered in the previous section. This short quiz does not count toward your grade in the class, and you can retake it an unlimited number of times. Use this quiz to check your understanding and decide whether to 1 study the previous section further or 2 move on to the next section.

Privacy Policy. Skip to main content. Module 7: Cell Division. Search for:. Figure 1. The cell cycle. Learning Outcomes Identify the characteristics and sub-phases of interphase Identify the characteristics and stages of mitosis Identify the characteristics of cytokinesis.

Figure 2. Stages of mitosis. Video Review: The Cell Cycle This video reviews all the steps of mitosis; seeing it all together is a great review at this stage. The spindles start to attach to the Kinetochores of centromeres of sister chromatids during Prometaphase. The first and longest phase of mitosis is prophase.

During prophase, chromatin condenses into chromosomes, and the nuclear envelope the membrane surrounding the nucleus breaks down. In animal cells, the centrioles near the nucleus begin to separate and move to opposite poles of the cell. Centrioles are small organelles found only in eukaryotic cells that help ensure the new cells that form after cell division each contain a complete set of chromosomes.

As the centrioles move apart, a spindle starts to form between them. During metaphase , spindle fibers fully attach to the centromere of each pair of sister chromatids.

The spindle fibers ensure that sister chromatids will separate and go to different daughter cells when the cell divides. Some spindles do not attach with the centromeres of chromosomes, rather, they attach with each other and grow longer.

The elongation of spindles not attached to the centromeres. They elongate the whole cell. This is visible in the figure below:. During anaphase , sister chromatids separate and the centromeres divide. The sister chromatids are pulled apart by the shortening of the spindle fibers. This is a little like reeling in a fish by shortening the fishing line. At the end of anaphase, each pole of the cell has a complete set of chromosomes. The chromosomes reach the opposite poles and begin to decondense unravel , relaxing once again into a stretched-out chromatin configuration.