THE CELL CYCLE
FUNCTIONS
The cell cycle is the regular sequence of growth and
division that cells undergo as they live life and divide to
make new cells.
The length of the cell cycle depends on the type of cell
Cell division has three functions: growth, repair of
damage and reproduction
HOW DO CELLS REPRODUCE?
• Cells reproduce ASEXUALLY: one parent cell divides and makes two
copies of itself
• The goal of asexual reproduction is to produce daughter cells that are
GENETICALLY IDENTICAL to the parent cell
WHAT HAPPENS??
During the cell cycle, cells grow, prepare for division and
divide into two new cells, which are called DAUGHTER
CELLS
There are three main stages to the cell cycle:
INTERPHASE
MITOSIS
CYTOKINESIS
DIAGRAM OF THE CELL CYCLE
during interphase,
the DNA is relaxed
in the form of
CHROMATIN (dna
and proteins)
WHAT HAPPENS TO THE DNA???
during mitosis, the
CHROMATIN coils
up tightly into a
structure called a
CHROMOSOME( or
SISTER CHROMATID)
after division, it goes
back to CHROMATIN
STAGE I:INTERPHASE
PREPARING TO DIVIDE
The first stage of the cell cycle is INTERPHASE
Cells spend most of their time
in INTERPHASE. During this
stage, they are growing,
living their life and preparing to divide
. This process has
three steps to it:
• G1- cell grows and lives
• S- makes a copy of the DNA
• G2- fixes mistakes in the DNA
copy and prepares to divide
STAGE TWO: MITOSIS
DIVIDING THE NUCLEAR MATERIAL
THE SECOND STAGE OF THE CELL CYCLE IS MITOSIS
MITOSIS IS THE PROCESS THAT DIVIDES THE NUCLEAR
MATERIAL
MITOSIS IS MADE UP OF FOUR PHASES:
PROPHASE
METAPHASE
ANAPHASE
TELOPHASE
PROPHASE
During PROPHASE, the cell begins to prepare to divide the nucleus
•
•
•
•
The CHROMATIN condenses into CHROMOSOMES
The centrioles move to opposite ends of the cell
Spindle fibers begin to grow from the centrioles
The nuclear membrane dissolves
METAPHASE
During metaphase, A spindle fiber attaches to each CHROMOSOME at the
CENTROMERE
the SISTER CHROMATIDS are moved to the middle of the cell and line up
on the equator of the cell
ANAPHASE
During ANAPHASE, the centromere holding the sister chromatids together
splits.
Each chromosome is pulled to opposite ends of the cell by their attached
spindle fiber
TELOPHASE
During TELOPHASE, the chromosomes reach the opposite ends of the cell,
where two nuclear membranes form around set.
The cell starts to form the cleavage furrow
Chromosomes relax back into chromatin
CYTOKINESIS
CYTOKINESIS is the process that divides the rest of the cell.
During cytokinesis, the cell membrane completes it’s split and the
cytoplasm of the cell is divided to form two new daughter cells,
which are EXACT COPIES of the parent cell