Transcript Glencoe Biology - Fort Thomas Independent Schools

Chapter 9
Cellular Reproduction
9.1 Cellular Growth
 As the cell grows, its volume increases
much more rapidly than the surface area.
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Cell Cycle
 Cell division prevents the cell from becoming
too large.
 It also is the way the cell reproduces so that
you grow and heal certain injuries.
 Cells reproduce by a cycle of growing and
dividing called the cell cycle.
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
 Interphase is the stage during which the
cell grows, carries out cellular functions,
and replicates.
 Mitosis is the stage of the cell cycle during
which the cell’s nucleus and nuclear material
divide.
 Cytokinesis is the method by which a cell’s
cytoplasm divides, creating a new cell.
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Stages of Interphase
 The first stage of interphase, Gap1
 The cell is growing, carrying out normal cell
functions, and preparing to replicate DNA.
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Second Stage of Interphase, S [Synthesis]
 The cell copies its DNA in preparation for
cell division.
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Third Stage of Interphase, Gap2
 The cell prepares for the division of its
nucleus.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
The Stages of Mitosis
 Prophase
 The cell’s chromatin tightens.
 Sister chromatids are attached at the
centromere.
 Two chromatids become one
chromosome.
 Spindle fibers form in the cytoplasm.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
 The nuclear
envelope seems
to disappear.
 Spindle fibers
attach to the sister
chromatids.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Metaphase
 Sister chromatids
are pulled along the
spindle apparatus
toward the center of
the cell.
 They line up in the
middle of the cell.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Anaphase
 The spindle apparatus begin to shorten.
 The sister chromatids separate.
 The chromosomes move toward the poles
of the cell.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
 The sister chromatids
now become separate
chromosomes.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Telophase
 The chromosomes arrive at the poles and
begin to relax.
 Two new nuclear membranes begin to form
and the nucleoli reappear.
 The spindle apparatus disassembles.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
 The pinching
between the newly
formed cells is an
indication of
telophase.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Cytokinesis
 In animal cells,
microfilaments constrict,
or pinch, the cytoplasm.
 In plant cells, a new
structure, called a cell
plate, forms.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
 Division of two
IDENTICAL daughter
cells with the same
amount of
chromosomes (DNA).
Chapter 9
Cellular Reproduction
Recap – Overview of Mitosis
Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Quality Control Checkpoints
 The cell cycle has built-in checkpoints that
monitor the cycle and can stop it if something
goes wrong.
 Spindle checkpoints also have been identified
in mitosis.
Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Abnormal Cell Cycle: Cancer
 Cancer is the
uncontrolled growth
and division of cells.
 Cancer cells can kill
an organism by
crowding out normal
cells, resulting in the loss of tissue function.
Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Causes of Cancer
 The changes that occur in the regulation of
cell growth and division of cancer cells are
due to mutations.
 Various environmental factors can affect the
occurrence of cancer cells.