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Class Starter
Using the diagram of a football field, write a short paragraph describing how the players,
the midfield line, and the goal posts compare to the structures of a cell involved in
mitosis and cell division.
Objectives
• What are the phases of the eukaryotic cell cycle?
• What are the four stages of mitosis?
• How does cytokinesis occur?
10.2: Mitosis
Eukaryotic Cell Cycle
• The __________________ is a ____________________ sequence of cellular
___________________________________________ during the life of a cell.
•
The life of a eukaryotic cell cycles through phases of __________________,
____________________________, _______________________________, and
_________________________________ and _____________________.
•
The cell cycle is made up of ________ phases. The first three phases together are
known as ___________________________. The remaining two phases make up
_______________________________.
Interphase
• During interphase, the cell is not dividing. It is ___________________________
to divide.
•
Different types of cells spend _________________________ amounts of time in
interphase.
•
Cells that divide often, such as skin cells, spend _________ time in interphase.
Cells that divide seldom, such as nerve cells, spend __________ of their time in
interphase.
•
During the __________________________ (G1), a cell grows rapidly as the cell
builds more _________________________. For most organisms, this phase
occupies the major portion of the cell’s life.
•
During the ____________________________ (S), a cell’s __________ is copied.
At the end of the S phase, the cell’s nucleus has _________________ as much
DNA as it did in the G1 phase.
•
During the _______________________________ (G2), the cell continues to
__________________________________ to divide. Hollow protein fibers called
microtubules are organized in the cytoplasm during G2.
•
What is the cell cycle?
Checkpoint
–
•
What takes place during the cycle in eukaryotes?
How many phases make up the cell cycle?
–
What are their names?
•
What are the 3 phases that make up interphase?
•
What happens in each phase?
Cell Division
• Each new cell requires a complete set of organelles, including a nucleus.
•
The process of dividing the nucleus into two daughter nuclei is called
_________________.
•
The process of separating the organelles and the cytoplasm is called
___________________________.
•
During mitosis, the _____________________ divides to form _______________.
Each nucleus contains a complete set of the cell’s _______________________.
•
The ________________________ breaks down briefly. The two sister chromatids
of each chromosome are pulled to the ____________________ sides of the
dividing cell.
•
As the nucleus divides, the ______________________ also begins to divide.
•
Each daughter cell receives about __________ of the original cell’s organelles.
•
During ____________________, the two daughter cells are physically separated.
Checkpoint
•
What is the difference between mitosis and cytokinesis?
•
Summarize the events of cell division.
•
What is the end product?
Stages of Mitosis
Stage 1 Prophase
• Within the nucleus, chromosomes begin to _________________ and become
visible under a light microscope.
•
The nuclear membrane ________________________. Outside the nucleus, a
special structure called the __________________ forms. The spindle is made up
of several _________________________.
•
Cells have an organelle called the ________________________, which helps
assemble the spindle.
•
In animal cells, the centrosome includes a pair of ______________________.
•
Before mitosis, the cell’s centrosome is duplicated. During prophase, the
centrosomes move to ____________________________________ of the cell.
Stage 2 Metaphase
• During metaphase, the __________________________ are packaged into their
most condensed form.
•
The nuclear membrane is fully __________________________, and the
condensed chromosomes move to the ___________________ of the cell and line
up along the cell’s equator.
•
Spindle fibers form a link between the poles and the _______________________
of each chromosome.
Checkpoint
•
What is the first phase of mitosis?
•
What happens during this phase?
•
What is the second phase of mitosis?
•
What happens during this phase?
Stage 3 Anaphase
• Once all of the chromosomes are lined up, the spindle fibers ________________.
•
___________________________ move toward opposite poles as the spindle
fibers that are attached continue to shorten.
•
Each pole now has a full set of _________________________.
Stage 4 Telophase
• A ________________________ forms around the chromosomes at each pole of
the cell.
•
Chromosomes, now at opposite poles, ______________ and change back to their
original _____________________ form.
•
The __________________ dissolves and the _______________________ break
down and disappear.
•
Mitosis is complete.
Checkpoint
•
What is the third phase of mitosis?
•
What happens during this phase?
•
What is the last phase of mitosis?
•
What happens during this phase?
Cytokinesis
• As ___________________ ends, cytokinesis begins. The ___________________
is separated, and _________ cells are formed.
•
During cytokinesis, the ________________________ grows into the center of the
cell and divides it into two __________________________ of equal size.
•
Each daughter cell has about half of the parent’s __________________________
_______________________________.
•
The end result of mitosis and cytokinesis is ______ genetically ___________cells
in place of the original cell.
Separating the Cytoplasm
• ________________________ holding cell wall material line up across the
______________________ of the cell.
•
These vesicles fuse to form a large, membrane-bound cell wall called the
__________________
•
When it is completely formed, the cell plate separates the plant cell into ______
new plant cells.
Continuing the Cell Cycle
• After cytokinesis is complete, each cell enters the _____________ of interphase.
•
The daughter cells are about equal in size—about half the size of the original cell.
•
The activity of each cell continues because each has its own _________________
_______________. The _______________________ continues for each new cell.
Checkpoint
•
When does cytokinesis begin?
•
Cytokinesis divides the cell contents in ____.
•
What is the result of this process?
•
How does cytokinesis in plants differ from animals?
•
After cytokinesis, what phase does the new cells enter?