Which Describes One Of The Main Differences Between Mitosis In Plant Cells And In Animal Cells?

seven.3: Mitotic Stage - Mitosis and Cytokinesis

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Divide and Split

Tin you gauge what this colorful prototype represents? Information technology shows a eukaryotic prison cell during the procedure of cell division. In particular, the image shows the nucleus of the cell dividing. In eukaryotic cells, the nucleus divides before the jail cell itself splits in two; and before the nucleus divides, the cell'due south DNA is replicated, or copied. There must be ii copies of the Deoxyribonucleic acid so that each girl cell will have a complete copy of the genetic material from the parent jail cell. How is the replicated Dna sorted and separated and then that each daughter prison cell gets a complete set of genetic material? To reply that question, you lot first demand to know more about DNA and the forms it takes.

Figure \(\PageIndex{1}\): Dividing prison cell stained with fluorescent dyes. You tin can see chromosomes in blue and spindles in green.

The Forms of Dna

Except when a eukaryotic cell divides, its nuclear DNA exists as a grainy material called chromatin. Only when a cell is near to divide and its DNA has replicated does DNA condense and curlicue into the familiar X-shaped form of a chromosome, like the i shown in Figure \(\PageIndex{2}\). Because Deoxyribonucleic acid has already replicated, each chromosome really consists of two identical copies. The ii copies of a chromosome are chosen sister chromatids. Sis chromatids are joined together at a region called a centromere.

Figure \(\PageIndex{two}\): Chromosome. Subsequently DNA replicates, it forms X-shaped chromosomes like the one shown here. 1. Chromatid, ii. Centromere, three. short arm, four. long arm. Centromere contains proteins chosen kinetochores (not shown) where spindles attach during mitosis.

The process in which the nucleus of a eukaryotic cell divides is chosen mitosis. During mitosis, the two sister chromatids that make up each chromosome separate from each other and motility to reverse poles of the cell. Mitosis occurs in four phases. The phases are called prophase, metaphase, anaphase, and telophase. They are shown in Figure \(\PageIndex{3}\) and described in detail beneath.

Figure \(\PageIndex{3}\): Mitosis is the phase of the eukaryotic prison cell cycle that occurs between DNA replication and the formation of 2 girl cells. Mitosis has four substages, prophase, metaphase, anaphase, and telophase.

Prophase

Figure \(\PageIndex{4}\): Prophase in later on stage is chosen prometaphase. The spindle starts to form during the prophase of mitosis. The spindles first 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 fauna cells, the centrioles most the nucleus begin to separate and move to opposite poles of the cell. Centrioles are pocket-size organelles constitute simply in eukaryotic cells that assist ensure the new cells that form after cell segmentation each comprise a consummate set of chromosomes. Every bit the centrioles move apart, a spindle starts to form between them. The blue spindle, shown in Effigy \(\PageIndex{4}\), consists of fibers made of microtubules.

Metaphase

During metaphase, spindle fibers fully adhere to the centromere of each pair of sister chromatids. As yous can meet in Effigy \(\PageIndex{5}\), the sis chromatids line up at the equator, or center, of the jail cell. The spindle fibers ensure that sister chromatids will carve up and get to different daughter cells when the cell divides. Some spindles do not attach to the kinetochore poly peptide of the centromeres. These spindles are called non-kinetochore spindles that help in the elongation of the prison cell. This is visible in Figure \(\PageIndex{v}\).

Figure \(\PageIndex{v}\): Chromosomes, consisting of sister chromatids, line up at the equator or eye of the cell during metaphase. The blueish lines are spindles, and the orange rectangles at the cell poles are centrioles. Some spindles from the opposing centrioles adhere with each other, and some spindles attach to the kinetochores of the sister chromosomes from their corresponding sides. Each chromosome is attached to ii spindles.

Anaphase

During anaphase, sister chromatids separate and the centromeres divide. The sis chromatids are pulled autonomously by the shortening of the spindle fibers. This is a little like reeling in a fish by shortening the line-fishing line. Ane sister chromatid moves to 1 pole of the cell, and the other sister chromatid moves to the opposite pole (see Effigy \(\PageIndex{half-dozen}\)). At the end of anaphase, each pole of the cell has a complete fix of chromosomes

Figure \(\PageIndex{six}\): Anaphase: Sister chromatids break autonomously and move to the opposite pole with the help of spindles. The newly separated sis chromatids are called chromosomes at present.

Telophase

The chromosomes achieve the opposite poles and begin to decondense (unravel), relaxing over again into a stretched-out chromatin configuration. The mitotic spindles are depolymerized into tubulin monomers that volition be used to assemble cytoskeletal components for each daughter cell. Nuclear envelopes course around the chromosomes, and nucleosomes appear within the nuclear area (run into Effigy \(\PageIndex{seven}\).

Figure \(\PageIndex{7}\): Telophase: The chromosomes decondense, spindles start to disappear, two nuclei form in a prison cell.

Cytokinesis

Cytokinesis is the terminal phase of cell sectionalization in eukaryotes as well equally prokaryotes. During cytokinesis, the cytoplasm splits in two and the cell divides. The procedure is different in plant and animal cells, equally y'all can see in Figure \(\PageIndex{8}\). In animal cells, the plasma membrane of the parent jail cell pinches in along the prison cell's equator until ii girl cells form. In the plant cells, a cell plate forms along the equator of the parent cell. Then, a new plasma membrane and cell wall form along each side of the cell plate.

Figure \(\PageIndex{viii}\): Cytokinesis is the final stage of eukaryotic cell segmentation. Information technology occurs differently in creature (left) and establish (right) cells. You can see a microfilament ring forming at the center of the elongated beast cell. This creates a depression chosen cleavage furrow. This invagination ultimately separates the prison cell cytoplasm into 2 cells. A cell plate forms at the centre of the elongated plant cell. And then a new plasma membrane and jail cell wall form along each side of the cell plate.

Review

1. Describe the different forms that DNA takes before and during jail cell division in a eukaryotic prison cell.
2. Identify the iv phases of mitosis in an animal cell, and summarize what happens during each phase.
3. Explain what happens during cytokinesis in an creature cell.
4. What are the master differences between mitosis and cytokinesis?
5. The familiar 10-shaped chromosome represents:
   1. How Deoxyribonucleic acid always looks in eukaryotic cells
   2. How Dna in eukaryotic cells looks one time it is replicated and the jail cell is about to split
   3. Female sex chromosomes merely
   4. How DNA appears immediately later cytokinesis
6. Which of the following is not part of a chromosome in eukaryotic cells?
   1. Centriole
   2. Centromere
   3. Chromatid
   4. Dna
7. What do you think would happen if the sister chromatids of one of the chromosomes did not split during mitosis?
8. Put the post-obit processes in order of when they occur during cell partition, from first to last:
   1. separation of sister chromatids
   2. DNA replication
   3. cytokinesis
   4. lining upward of chromosomes in the center of the cell
   5. condensation and coiling of DNA into a chromosome
9. Why do you retrieve the nuclear envelope breaks down at the commencement of mitosis?
10. What are the fibers fabricated of microtubules that adhere to the centromeres during mitosis are called?
11. True or Faux. Chromosomes begin to uncoil during anaphase.
12. True or False. During cytokinesis in creature cells, sis chromatids line upwardly along the equator of the cell.
13. True or Faux. After mitosis, the result is typically two girl cells with identical Deoxyribonucleic acid to each other.

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Source: https://bio.libretexts.org/Bookshelves/Human_Biology/Book:_Human_Biology_%28Wakim_and_Grewal%29/07:_Cell_Reproduction/7.3:_Mitotic_Phase_-_Mitosis_and_Cytokinesis

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