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Science Fusion PowerNotes used by Paoli Community School Corp.
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Unit 7 Lesson 1 Mitosis
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 Lesson 1 Mitosis
Indiana Standards
Copyright © Houghton Mifflin Harcourt Publishing Company
• 8.3.1 Explain that reproduction is essential for the continuation of every species and is the mechanism by which all organisms transmit genetic information.
• 8.3.3 Explain that genetic information is transmitted from parents to offspring mostly by chromosomes.
• 8.3.4 Understand the relationship between deoxyribonucleic acid (DNA), genes, and chromosomes.
Splitsville!
Copyright © Houghton Mifflin Harcourt Publishing Company
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 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 Lesson 1 Mitosis
What happens to genetic material during cell division?• A duplicated chromosome is made of two identical
structures called chromatids.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 Lesson 1 Mitosis
Around and Around
Copyright © Houghton Mifflin Harcourt Publishing Company
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 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 Lesson 1 Mitosis
Phasing Out
Copyright © Houghton Mifflin Harcourt Publishing Company
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 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 Lesson 1 Mitosis
What are the phases of mitosis?
• In metaphase, the chromosomes line up in the middle of the cell.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 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.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 7 Lesson 1 Mitosis