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Topic: Reproduction and Development Aim: How do cells divide? Do Now: Explain the differences between sexual and asexual reproduction. What types of things reproduce sexually? Asexually? HW: PAGE 96-97 10 MAIN POINTS & FINISH HANDOUT
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What are the two types of reproduction? Asexual reproductionAsexual reproduction Sexual reproductionSexual reproduction MITOSIS MEIOSIS
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What is ASEXUAL Reproduction? Requires one parent that dividesRequires one parent that divides – Asexual “A”parent Offspring are identical to parentsOffspring are identical to parents Same # of chromosomesSame # of chromosomes
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How does ASEXUAL reproduction occur? MITOSIS – cell divisionMITOSIS – cell division One cell divides into two identical daughter cells (same # of chromosomes as parent)One cell divides into two identical daughter cells (same # of chromosomes as parent) Occurs in all body cells EXCEPT sex cellsOccurs in all body cells EXCEPT sex cells
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What are the steps of Mitosis? InterphaseInterphase ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase –Cytokinesis
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Interphase The mass of DNA inside the nucleus during interphase is known as CHROMATIN. CHROMATIN
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Prophase
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Metaphase
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Anaphase
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Telophase
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What are the steps of Mitosis? 1.INTERPHASE: cell grows to mature size and chromatin replicate (makes copy of DNA) 2.PROPHASE: chromatin forms chromosomes, nuclear membrane disappears and spindle fibers form 3.METAPHASE: chromosomes line up in the Middle of the cell 4.ANAPHASE: chromosomes separate and move Away from each other 5.TELOPHASE: nuclear membrane starts to form
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What is Cytokinesis? Part of telophasePart of telophase Cell membrane pinches in (cytoplasm separates) resulting in 2 new cellsCell membrane pinches in (cytoplasm separates) resulting in 2 new cells CYTOKINESIS
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How is mitosis different in plant cells? 1.Cell membrane DOES NOT pinch in Instead a CELL PLATE forms between 2 new cellsInstead a CELL PLATE forms between 2 new cells 2.Plant cells do not have centrioles (animal cells do) CELL PLATE
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Cytokinesis – Animal and Plant
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What is Cancer? Abnormal and uncontrolled cell division
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What are the different types of ASEXUAL Reproduction? 1.Binary Fission – one celled organism divides into two identical cells (mitosis) Binary Fission means “equal division” Examples: ameba and paramecia 2.Budding – unequal division of organisms Examples: hydra, yeast 3.Sporulation – spores (specialized cells) develop into new organisms (mitosis) Examples: mold, mushrooms
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What are the different types of ASEXUAL Reproduction? 4.Vegetative Propagation – Asexual reproduction used by plants a.Runners (strawberries) b.Buds (potatoes) c.Grafting (roses) d.Bulbs (onions)
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Binary Fission & Budding BINARY FISSIONBUDDING
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Sporulation
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Vegetative Propagation RUNNERS BUDS GRAFTING BULBS
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Topic: Reproduction and Development Aim: What is sexual reproduction? Do Now: Why does sexual reproduction require two parents?
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What is sexual reproduction? Requires 2 parent cells, each with half the normal number of chromosomes Involves sex cells Human: sperm + egg → zygote 23 + 23 → 46
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What is meiosis? Cell division occurs only in sex organs to produce sex cells (sperm and egg) Produces 4 daughter cells with half the number of chromosomes as parent cell (23 in humans) 2 divisions (1 → 2 → 4)
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Meiosis
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How does meiosis occur in males? Occurs in testes to produce sperm Produces 4 new sperm cells
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How does meiosis occur in females? Occurs in ovaries Produces 1 egg cell and 3 polar bodies
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What is fertilization? Union of egg and sperm to form a zygote Two types: Internal fertilization: occurs inside the female (humans) External fertilization: occurs outside the female (frogs); can occur on land or in water
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What happens to the zygote after fertilization? Zygote divides by MITOSIS to form 3 layers that will develop into different parts of the embryo 1.Outer layer: forms the skin and nerves 2.Middle layer: forms muscles 3.Inner layer: forms heart and stomach Outer layer Middle layer Inner layer
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