The Cell Cycle
What controls the life and development of a cell?
WHY?
An old piece of poetry says "to everything there is a season... a time to be born, a time to die." For cells, the line
might say "a time to divide and a time to grow." In multicellular organisms, different types of cells have different
roles and need to complete specific tasks. For example, a cell that isn't large enough is not useful forstoring
nutrients for later, but a cell that is too large will not be useful for transportation through a tiny capillary. In this
activity, you will learn about the seasons of a cell's life, and in turn better understand how
organisms function.
Model 1 - The cell cycle
1. How many phases are in the cell cycle as shown in the diagram in Model 1?
Four.
2. Starting at the starred cell, what is the order of the stages of a cell's life?
1' 2'
3. During which phase does the size of the cell increase?
G1
4. During which phase does the number of cells increase?
M.
5. Considering your answer to Questions 3 and 4, identify two ways that the growth of an organism canbe
accomplished through the events of the cell cycle.
The Cell Cycle 113
, Growth can happen when cells increase in size or when the number ofcells in an organism increases
(this takes place during Gl and M, respectively).
The Cell Cycle 114
What controls the life and development of a cell?
WHY?
An old piece of poetry says "to everything there is a season... a time to be born, a time to die." For cells, the line
might say "a time to divide and a time to grow." In multicellular organisms, different types of cells have different
roles and need to complete specific tasks. For example, a cell that isn't large enough is not useful forstoring
nutrients for later, but a cell that is too large will not be useful for transportation through a tiny capillary. In this
activity, you will learn about the seasons of a cell's life, and in turn better understand how
organisms function.
Model 1 - The cell cycle
1. How many phases are in the cell cycle as shown in the diagram in Model 1?
Four.
2. Starting at the starred cell, what is the order of the stages of a cell's life?
1' 2'
3. During which phase does the size of the cell increase?
G1
4. During which phase does the number of cells increase?
M.
5. Considering your answer to Questions 3 and 4, identify two ways that the growth of an organism canbe
accomplished through the events of the cell cycle.
The Cell Cycle 113
, Growth can happen when cells increase in size or when the number ofcells in an organism increases
(this takes place during Gl and M, respectively).
The Cell Cycle 114
