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Ch 9 The Cellular Basis of LifeCh 9 The Cellular Basis of Life

9.1 Cells come from 9.1 Cells come from CellsCells

Cells are needed forCells are needed for

MitosisMitosis: repair, growth,: repair, growth,

asexual reproduction (clones of one asexual reproduction (clones of one parent)parent)

MeiosisMeiosis: sexual reproduction: sexual reproduction

(two parents)(two parents)

Video clip (3 minute overview of mitosis/cancer)Video clip (3 minute overview of mitosis/cancer)

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9.2 The cell cycle multiplies cellsDifferent number of chromosomes for each organism (humans have 46)

Interphase: Chromosomes duplicate before the cell divides

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Mitosis- nucleus divided

and Cytokinesis-cell divides

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9.3 Mitosis9.3 Mitosis

Prophase=Prophase=pairspairs

Metaphase=Metaphase=middlemiddle

Anaphase=Anaphase=awayaway

Telophase=Telophase=twotwo

Cytokinesis Cytokinesis animalsanimals

Cell plate Cell plate plantsplants

Onion root tipOnion root tip

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9.4 Cancer

Cancer is due to uncontrolled cell cycle Benign –local tumor Malignant- travels around body by

metastasis

Treatment=surgery, radiation,

chemotherapy

(some disrupt mitotic spindle)

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9.5 Meiosis is used in sexual reproduction Meiosis only occurs in sperm and egg so

the new offspring doesn’t have double the chromosome number

Diploid Haploid Chick embryo Pig embryo Human embryo

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Meiosis- two divisions

Results in four cells

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9.6 Meiosis increases 9.6 Meiosis increases genetic genetic variationvariation

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Crossing overCrossing over

In MeiosisIn Meiosis