Unit 6 Lesson 1 Mitosis Copyright © Houghton Mifflin Harcourt Publishing Company.
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Transcript of Unit 6 Lesson 1 Mitosis Copyright © Houghton Mifflin Harcourt Publishing Company.
Unit 6 Lesson 1 Mitosis
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 6 Lesson 1 Mitosis
Florida Benchmark
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• SC.7.L.16.3 Compare and contrast the general processes of sexual reproduction requiring meiosis and asexual reproduction requiring mitosis.
Splitsville!
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Why do cells divide?
• Cell division takes place for different reasons.
• Cell division is important for asexual reproduction, which involves only one parent organism.
• Most growth in a multicellular organism happens because cell division produces new cells.
• Cell division produces cells for repair.
Unit 6 Lesson 1 Mitosis
What happens to genetic material during cell division?• The genetic material in cells is called DNA.
• In eukaryotic cells, DNA is found in the nucleus.
• A DNA molecule contains the information that determines the traits that a living thing inherits and needs to live.
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Unit 6 Lesson 1 Mitosis
What happens to genetic material during cell division?• During most of a cell’s life cycle, DNA is found in a
mass of loose strands called chromatin.
• Before cell division, DNA is duplicated.
• As cell division begins, the chromatin are compacted into visible structures called chromosomes.
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Unit 6 Lesson 1 Mitosis
What happens to genetic material during cell division?• A duplicated chromosome is made of two identical
structures called chromatids.
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Unit 6 Lesson 1 Mitosis
Around and Around
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What are the stages of the cell cycle?
• The life cycle of a eukaryotic cell, called the cell cycle, can be divided into three stages: interphase, mitosis, and cytokinesis.
Unit 6 Lesson 1 Mitosis
What are the stages of the cell cycle?
• Interphase is the stage in the cell cycle during which the cell is not dividing.
• The cell grows to about twice the size it was when it was first produced. It produces various organelles and engages in normal life activities.
• Changes that occur during interphase prepare a cell for division.
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Unit 6 Lesson 1 Mitosis
What are the stages of the cell cycle?
• In eukaryotic cells, mitosis is the part of the cell cycle during which the nucleus divides.
• Prokaryotes do not undergo mitosis because they do not have a nucleus.
• Mitosis results in two nuclei that are identical to the original nucleus.
• When mitosis is complete, the cell has two identical sets of chromosomes in two separate nuclei.
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Unit 6 Lesson 1 Mitosis
What are the stages of the cell cycle?
• Cytokinesis is the division of the parent cell’s cytoplasm.
• Cytokinesis starts during the last step of mitosis and eventually forms two complete cells.
• In plant cells, a cell plate forms during cytokinesis. The cell plate separates the cell into two new cells.
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Unit 6 Lesson 1 Mitosis
Phasing Out
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What are the phases of mitosis?
• There are four phases of mitosis: prophase, metaphase, anaphase, and telophase.
• By the end of the four phases, the cell will have two identical nuclei.
Unit 6 Lesson 1 Mitosis
What are the phases of mitosis?
• In prophase, the chromatin in the nucleus condense into chromosomes. The membrane around the nucleus breaks down.
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Unit 6 Lesson 1 Mitosis
What are the phases of mitosis?
• In metaphase, the chromosomes line up in the middle of the cell.
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Unit 6 Lesson 1 Mitosis
What are the phases of mitosis?
• In anaphase, each chromosome breaks up into two chromatids. They are pulled to opposite sides of the cell.
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Unit 6 Lesson 1 Mitosis
What are the phases of mitosis?
• In telophase, a new nuclear membrane forms around each group, and the chromosomes unwind into chromatin.
• After telophase, cytokinesis begins.
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Unit 6 Lesson 1 Mitosis
What are the phases of mitosis?
• After mitosis, cytokinesis results in two new cells, and the two new cells start the cell cycle again.
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Unit 6 Lesson 1 Mitosis