1 1 asexual reproduction mitosis. how do little elephants grow up to be big elephants?
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1 1
Asexual ReproductionMitosis
How do little elephants grow up to be BIG elephants?
The process of asexual reproduction begins
after a sperm fertilizes an egg.
Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun.
Cell that reproduce by asexual reproduction reproduce constantly.
Animated Mitosis Cyclehttp://www.cellsalive.com/mitosis.htm
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase & Cytokinesis
• Chromosomes are copied (# doubles)• Chromosomes appear as threadlike coils
(chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase
CELL MEMBRANENucleus
Cytoplasm
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
• Mitosis begins (cell begins to divide)• Centrioles (or poles) appear and begin to
move to opposite end of the cell. • Spindle fibers form between the poles.
CentriolesSister chromatids
Spindle fibers
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Spindle fibers
Centrioles
• Chromatids (or pairs of chromosomes) attach to the spindle fibers.
Centrioles
Spindle fibers
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
• Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell.
Centrioles
Spindle fibers
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
• Two new nuclei form. • Chromosomes appear as chromatin
(threads rather than rods).• Mitosis ends.
NucleiNuclei
Chromatin
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
• Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- ReviewInterphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
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- Cell Division
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A cell grows, prepares for division, and divides to form 2 daughter cells
FOUR phases:1. G1 (gap 1)2. S phase (synthesis, DNA replication)3. G2 (gap 2)4. M phase (mitosis)
Interphase(G1, S, G2)
MitosisProphaseMetaphaseAnaphaseTelophase
Cytokinesis
chromosome: X-shaped coiled piece of two identical DNA pieces
chromatid: individual pieces of coiled DNA (1/2 of the X)
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
two daughter cells have identical copies of the parent cell’s DNA
# of chromosomes is the same in both cells (called the diploid #)
A microscope was used to examine onion root tips. 4 different fields (A, B, C, and D) were used. In each field, the cells in the mitotic phases were identified and counted. Cells in interphase were also counted. What does this data reveal?
Area A Area B Area C Area D Total
Interphase 30 23 34 22 109
Prophase 3 4 3 2 12
Metaphase 6 3 2 4 15
Anaphase 3 1 2 1 7
Telophase 0 2 1 1 4
A human cell has 46 individual chromosomes in its cells. After the S phase of the cell cycle, how many chromosomes will the cell contain?
How many homologous (or matching) pairs of chromosomes will the cell have at prophase?
