English, asked by parveenshaheen118, 10 hours ago

It was avery important day for Ryan-hewas about to make his first public speech His teacher, Mr. Larson, had assigned
the class to choose a book, read it and make a speech about it Ryan had chosen a book he liked He had read it
carefully. Then, he had written down what he wanted to say about the book and prepared a speech He had practised
his speech many times, but he was nervous. Ryan didn't know whether he would be successful. He didn't want to
embras himself in front of the das Finally, Mr. Larson said the words Ryan had been dreading. "Okay. Ryan, let's
hear what you have to say. Come up and give us your presentation." Ky an gulped a few times. He couldn't help still
feding somewhat anxious. Then, he gathered his notes, straightened up and walked slowly to the front of the room
Mr. Larson sat down in one of the front row seats and gave Ryan an encouraging smile as he nodded for him to begin.
Ryan dered his throx, glanced at his note, and plunged into his presentation for a moment a two, Ryan still felt
very nervous. But as he went trough his speech he felties and less like running away. He had practised often enough
so that nothing in his speech was new to him anymore. It wasn't long before he relaxed a little and was able to a most
enjoy what he was doing. By the time Ryan finished his presentation, he felt almost comfortable When Ryan stopped
speaking, everyone in the class applauded Mr. Larson sa. "That was a very well-prepared presentation, Ryan You
did an excellent job"Ryan thought about how much he had practised to get ready for his speech, and he felt proud. He
will didn't like making speeches, but now he knew he could do it.

a.Give a suitable title for the above passage.

Answers

Answered by prashantk3067

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Mitosis

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For the type of cell division in sexually-reproducing organisms used to produce gametes, see Meiosis. For excessive constriction of the pupils, see Miosis. For the parasitic infestation, see Myiasis. For muscle inflammation, see Myositis.

In cell biology, mitosis (/maɪˈtoʊsɪs/) is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which the total number of chromosomes is maintained.[1] Therefore, mitosis is also known as equational division.[2][3] In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (during which the DNA is replicated) and is often followed by telophase and cytokinesis; which divides the cytoplasm, organelles and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components.[4] The different stages of Mitosis altogether define the mitotic (M) phase of an animal cell cycle—the division of the mother cell into two daughter cells genetically identical to each other.[5]

Mitosis in an animal cell (phases ordered counter-clockwise).

Mitosis divides the chromosomes in a cell nucleus.

Label-free live cell imaging of Mesenchymal Stem Cells undergoing mitosis

Onion (Allium) cells in different phases of the cell cycle enlarged 800 diameters.

a. non-dividing cells

b. nuclei preparing for division (spireme-stage)

c. dividing cells showing mitotic figures

e. pair of daughter-cells shortly after division

The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are prophase, prometaphase, metaphase, anaphase, and telophase. During mitosis, the chromosomes, which have already duplicated, condense and attach to spindle fibers that pull one copy of each chromosome to opposite sides of the cell.[6] The result is two genetically identical daughter nuclei. The rest of the cell may then continue to divide by cytokinesis to produce two daughter cells.[7] The different phases of mitosis can be visualized in real time, using live cell imaging.[8] Producing three or more daughter cells instead of the normal two is a mitotic error called tripolar mitosis or multipolar mitosis (direct cell triplication / multiplication).[9] Other errors during mitosis can induce apoptosis (programmed cell death) or cause mutations. Certain types of cancer can arise from such mutations.[10]

Mitosis occurs only in eukaryotic cells. Prokaryotic cells, which lack a nucleus, divide by a different process called binary fission[citation needed]. Mitosis varies between organisms.[11] For example, animal cells undergo an "open" mitosis, where the nuclear envelope breaks down before the chromosomes separate, whereas fungi undergo a "closed" mitosis, where chromosomes divide within an intact cell nucleus.[12] Most animal cells undergo a shape change, known as mitotic cell rounding, to adopt a near spherical morphology at the start of mitosis. Most human cells are produced by mitotic cell division. Important exceptions include the gametes – sperm and egg cells – which are produced by meiosis.

Discovery

Phases

Function

Variations

Diagnostic marker

Related cell processes

Evolution

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