Upload
madison-briggs
View
221
Download
5
Embed Size (px)
Citation preview
Cell DivisionA cell grows in size by increasing both the
size and the number of its cells. Then 2 grow and divide, forming and so on.
Cell Cycle: The regular sequence of growth and division that cells undergo
Cell cycle is also known as the Mitosis cycle.
Asexual Reproduction – Mitosis The process in which the nucleus divides to
form two new nuclei
Three reasons why cells reproduce by asexual reproduction:
1. Growth 2. Repair 3. Replacement
Cells that reproduce by asexual reproduction reproduce constantly.
Mitosis Cycle
• Three stages:
1. Interphase
2. Mitosis• Prophase• Metaphase• Anaphase• Telophase
3. Cytokinesis
Interphase occurs before mitosis begins
• Interphase is considered to be the 'living' phase of the cell, in which the cell obtains nutrients, grows to full size, reads its DNA, and conducts other "normal" cell functions.
• Majority of the life of the cell
CELL MEMBRANENucleus
Cytoplasm
Interphase:considered to be the 'living' phase of the cell, in which the cell obtains nutrients,
grows, reads its DNA, and conducts other "normal" cell functions.
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Stage 2: MitosisMitosis begins – cells begin to divide
Scientists divide mitosis into 4 parts, or phases:1.Prophase2.Metaphase3.Anaphase4.Telophase
Phase 1 Prophase• Centrioles (or poles) appear and begin to move to
opposite end of the cell. • Spindle fibers form between the poles.• Nuclear envelope breaks down
CentriolesSister chromatids
Spindle fibers
Prophase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Spindle fibers
Centrioles
Phase 2: Metaphase• Chromosomes attach to the spindle fibers at its centromere (center).
The Chromosomes line up across the center of cell.
Spindle fibers
Metaphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Phase 3: AnaphaseThe chromosomes split in half.Each side of the newly split chromosome move to opposite ends of the cell.
Centrioles
Spindle fibers
Anaphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Phase 4: Telephase• Two new nuclei form. • Chromosomes appear as chromatin (threads
rather than rods).• A new nuclear envelope forms around each region
of chromosomes.• Mitosis ends.
NucleiNuclei
Chromatin
Telophase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Stage 3: Cytokinesisoccurs after mitosis
• Final stage of the cell or mitosis cycle.
• Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.
Typical Cell cycle in an animal cell
Time to complete cycle?How long it takes
for a cell to go through mitosis depends on the cell. A human liver cell, for example, completes one cell cycle in about 22 hours.
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- ReviewInterphase
Prophase
Metaphase
Anaphase
Telophase
Interphase