Cell Reproduction Mitosis Meiosis Creates 2 identical cells
Creates 4 different cells Creates body cells Body cells, Skin
Cells, Tissues, Organs Creates sex cells Sperm and egg 2 Diploid
cells = 2n or 2 sets of chromosomes Haploid cells = 1n or 1 set of
chromosomes
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____________________ Increase in number of cells. Replace worn
out or damaged cells. 3
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4
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1. Gap 1: Cell Growth 2. Synthesis: DNA Replication 3. Gap 2:
Preparation of Mitosis 4. Mitosis Interphase A long period of cell
growth 5
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G1 Phase: The cell grows in size. S Phase: DNA # is doubled. G2
Phase: gets ready for mitosis. Develops its organelles. Checkpoint
1 *Has 2 complete sets of DNA Checkpoint 2 6
Condensed, duplicated chromosome or sister chromatids chromatid
centromere Holds the duplicated chromosome together G2 phase: Cell
gets ready for mitosis 9 Chromatid
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Centrioles copies are made 1. More cytoplasm- cell grows. 2.
DNA is being replicated. 3. More organelles The cell is getting
ready for MITOSIS, cell division. ***DNA is in the form of
Chromatin (ball of DNA) 10
X X X X 2. Nuclear Membrane Breaks down 3. Centrioles move
apart. 1.Chromatin forms visible chromosomes 4. Fibers form 12
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1. DNA2. Nuclear Membrane 3. Centrioles4. Fibers Chromatin
condenses into visible chromosomes Begins to break down Move apart
from one another in opposite directions Form between centrioles
13
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XX XX 4.THE NUCLEAR MEMBRANE IS NO LONGER PRESENT 2. Spindle
fibers connect to the sister chromatids 3. Sister chromatids are
lined up along the middle of the cell. 1. Centrioles move to
opposite poles. 14
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1. Centrioles2. Fibers3. DNA4. Nuclear Membrane Continue to
move to opposite ends of the cell Is completely gone Sister
chromatids are pulled to the middle of the cell 15 Attach to the
sister chromatids.
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> > > > > > > > 2.Centrioles begin to
pull the chromosomes toward the opposite sides of the cell. 1.
Sister Chromatids separate 16
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1.Sister Chromatids 2.Fibers3.Centrioles4.Nuclear Membrane
Pulled apart Each chromatid is separate from its sister Still at
opposite sides of the cell Pull each chromatid toward opposite ends
of cell Is still gone 17
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>> > > > > > > 3.Cell Membrane pinches
at center 2. Nuclear Membrane begins to reappear 4. Fibers begin to
disappear 1.Chromosomes are at opposite sides of the cell 18
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1.Sister Chromatids 2.Nuclear Membrane 3.Cell Membrane 4.Fibers
Each end of cell has a complete set of chromosomes. Begins to
reform around the sets of chromosomes Begins to pinch at the
center, forming two new identical cells Begin to disappear 19
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Cell Membrane splits into two new identical cells 20
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Phases of Mitosis: Prophase Metaphase Anaphase Telophase
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Another Animation of Mitosis Cell Cycle of Mitosis Control of
the cell cycle Interactive review of mitosis from Classzone.com
Video clips 23
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The process is VERY SIMILAR in each type of cell. There are
only 2 differences: 1.Plant cells do not have centrioles 2.The cell
membrane cannot pinch because of the cell wall. 3.Instead a cell
plate forms between the 2 nuclei division. 24
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_______________________ 25
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External factors Physical signal cell to cell contact. Once a
cell touches another cell it stops dividing. When cells fail to
respond to the external signal, the cells continue to divide
uncontrollably and form clumps. Tumor is a clump of cancer cells.
Benign tumor is harmless, the cells are clustered together tightly
and can be removed. Malignant tumor is bad, the cells can break
away and be carried to other parts of the body. When a tumor has
metastasized, it means the cancer cells have spread to other parts
of the body. 26
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Cancer cells do not perform the specialized functions needed by
the body. In the lung cancer cells do not exchange oxygen and
carbon dioxide. In the brain they do not transmit the messages
needed to interpret information to the body Can exert great
pressure on surrounding organs. 27
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Carcinogen a substance known to produce or promote the
development of cancer cells. 28
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cancer cell bloodstream normal cell 29
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Cuts chromosome number in half. Creates haploid cells. Creates
sperm and egg Spermatogenesis the creation of sperm Oogenesis the
creation of ova (egg) 30
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Sperm or Eggs In males: These cells develop into 4 individual
sperm that are genetically different from the parent cell. In
females: These cells would have developed into 3 small polar bodies
which will die and only 1 large egg. (THIS IS DUE TO AN UNEVEN
DIVISION OF CYTOPLASM DURING MEIOSIS) 31
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Fertilization: Union of sperm and Egg Creates a zygote
Re-establishes the full number of chromosomes 2 chromosomes 4
chromosomes 32
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For growth and to replace old, worn out cells. Occurs in body
cells Two cells from 1 cell Identical cells to the parent cell.
Same number of chromosomes as the original (2N) - diploid One
division of the nucleus. To make sperm and eggs with Occurs in sex
cells Four cells from 1 cell Genetically different from the parent
cell. Half the number of chromosomes (1N) - haploid Two divisions
of the nucleus. 33