Transcript Cell Division

Mitosis
 Common
to most living things
 Sequence of growth and division of a cell.
Interphase
 Period of growth for a cell
 Majority of time spent in this phase (95%)
 Grows in size
 Metabolic processes
 Chromosomes are duplicated
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Preparation for division
Interphase
 3 parts
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G1(Growth Stage 1)
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S (Synthesis Stage)
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First growth phase.
Protein production is high
Continues to grow
Copies genetic material
G2 (Growth Stage 2)
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Second Growth Phase
Cell completes preparations for cell division
Cytoplasmic Organelles are replicated
Fill in where Interphase belongs along with the
different stages of interphase!
1.
2.
3.
The cell cycle is :
a. the division of a cell
b. the growth of a cell
c. the death of a cell
d. both A and B
Which stage of interphase is DNA replicated?
a. G1
b. S
c. G2
d. G3
Which of the following does not occur in interphase?
a. metabolic processes
b. growth
c. cell division
d. replication of cytoplasmic organelles
Cell Division
 Mitosis
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Happens in ALL cells.
Short amount of time (≥5%)
Occurs when cell reaches max size
Four Major Stages:
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Prophase
Metaphase
Anaphase
Telophase
Prophase (Early)
 First Phase
 Longest Phase
 Chromatin coils up to visible chromosomes
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Contains duplicate sister chromatid
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Held together by centromeres
Each are exact copies
 Prophase
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(Early)
Nucleus begins to disappear
Nucleolus and nuclear envelope disintegrate
 Prophase
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Nucleolus and nuclear envelope are gone
Centrioles
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(Late)
Normally outside of nucleus
Now migrate to opposite ends of cell
Involved in Chromatid separation
Spindle and Spindle Fibers form
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Football Shape, Cage like structures
Fibers extend from them
Vital role in Chromatid separation
 Metaphase---Second
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Phase
Doubled Chromosomes attach to spindle fibers by
their centromeres
Chromosomes are pulled to the middle of the cell
Each sister chromotid is attached to its own fiber
which will pull them to different sides of the cell
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Ensures that each new cell receives an identical and
complete set of chromosomes.
 Anaphase---3rd
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phase
Separation of sister chromatids begins
Centromeres split
Chromatid pairs separate
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Pulled apart by the shortening of the microtubules in
the spindle fibers
 Telophase---4th
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Phase
Chromatids reach opposite poles of the cell
Changes made in prophase are reversed
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Chromosomes unwind
 Start metabolic processes
Spindle Fibers break down
Nucleolus reforms
Nuclear envelope forms
Fill in where “Mitosis” belongs along with the
four stages!
In which stage of mitosis are the chromosomes pulled to the
middle of the cell?
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
In which stage of mitosis do the spindle and spindle
fibers form?
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
1.
In which stage of mitosis do the sister
chromatids split?
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
2.
In which stage of mitosis do the nucleolus
and nuclear envelope reappear?
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
 Dividing
of cytoplasm
 Occurs after telophase
 Different in plants and animals
 Animals
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Plasma membrane pinches in along the equator
Proteins under plasma membrane contract and slide
past each other
Continue to contract until cell in pinched in two
 Plants
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Plasma membrane does not pinch in
Cell plate is laid down across the cells equator
New membrane forms around each cell
Cell wall forms on each side of the plate
 Animal
 Plant
Fill in the concept map where “Cytokinesis”
belongs!
 Genetic
continuity
 Growth and Repair
 Two new daughter cells with identical
chromosome sets
 Unicellular organisms multiplied
 Multicellular organisms growth and
reproduction results in tissues..organs…organ
systems…survival of organism.
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Work together to perform a specific function
Parent Cell
2n
2n
Daughter Cells
2n
 http://www.youtube.com/watch?v=VlN7K1-
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