Cell Reproduction I. Introduction A. History

1. R. R. Brown, 1840’s, existence of the nucleus or “brain of the cell” 2. W. W. Fleming 1860’s dark staining threads appeared to “dance” 3. A. A. Weismann in 1887 proposed meiosis for sex cells outlined the steps of mitosis

II. Strategies A. Prokaryotes

Prokaryotes reproduce by 1. Binary fissionor by2. Endospore formation Figure 17.11Figure 17.11

B. Eukaryotes 1. Asexual

1. Asexual methods are for replacing cells by mitosis a. Animals do fission, budding, and/or fragmenting Advantage

FissionBudding Figure 46.1

Fragmenting Figure 8.1

1. Asexual methods replace cells by mitosis b. Plants do runners, spore formation, or budding c. Fungi do budding or spore formation d. Protistans are just weird

2. Sexual

2. Sexual = similar yet variation  meiosis a. Plants do alternation of generations  sporophyte and a gametophyte generation. Figure 18.3

b. Fungi same strategy as plants c. Protists again weird d. Animals male and female interactions but variances are parthenogenesis, hermaphroditic, sequential hermaphroditic (protogynous = female first or protandrous = male first)

hermaphroditic

Sequential Hermaphroditic = Protogynous vs. Protandrous

d. Animals male and female interactions, but variances are monoecious, dioecious, monogamy, polygamy, and others.

Monoecious Dioecious

Monogamy Polygamy

III. Cell Cycle A. Definition B. Stages

The Cell Cycle Figure 8.3

C. Controls 1. External

External controls  outside influence What could be a signal?

Cell contact can inhibit cellular growth.

2. Internal

Internal controls == internal clock Figure 8.9

Apoptosis = programmed cell death Figure 8.11

D. Cancer

Cancer == benign, malignant, or metastatic Figure 8.12

Figure 8.13 Figure 8.14

IV. Mitosis A. Definition B. Phases

Mitosis == prophase, metaphase, anaphase, and telophase plus interphase Figure 8.5

Prophase = condense chromatids, dismantle nuclear membrane, and start to build spindle Metaphase = attach chromatids to spindle fibers via centromere and line up chromatids across equator Anaphase = move chromatids toward poles Telophase = reverse steps of Prophase Interphase = time between mitotic divisions and does G1, G1, S, and G2 G2 of cycle

V. Cytokinesis A. Definition B. Strategies

PlantsAnimals Figure 8.8Figure 8.7

VI. Meiosis A. Definition B. Phases

Figure 9.6 Figure 9.7

VII. Comparison

Figure 9.8

VIII. Variation from Meiosis A. Independent Assortment

Figure 10.8 Figure 10.8

B. Random Fertilization

C. Problems 1. Whole Chromosomes

Figure 9.9 a. Non-disjunction is the failure of homologous pairs to separate in meiosis I b. or sister chromatids to separate in meiosis II.

2. Parts of Chromosomes

a. Anaphase of meiosis I DeletionsDuplications Figure 13.3 Figure 13.4

TranslocationsInversions Figure 13.5 Figure 13.6 Are these good or bad?

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