Transcript Cellular Reproduction - Fort Thomas Independent Schools

Chapter 9
Cellular Reproduction
Where were we and where are we
going next?
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
• Overview of Cell Division
– Mitosis and Meiosis
• Asexual and Sexual Reproduction
• Diploid vs. Haploid
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Mitosis
Meiosis
• Asexual reproduction
• Growth and repair
• Somatic chromosomes (body
chromosomes)
• Diploid (2n)
• No Crossing Over
• Produces identical daughter
cells
• Sexual Reproduction
• Passing of genetic traits
• Sex chromosomes aka
gametes (X and Y)
• Haploid (n)
• Crossing Over
• Produces genetically different
daughter cells
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Asexual
Reproduction
Sexual
Reproduction
• No genetic diversity
• Can refer to the production of
offspring from one parent
(binary fission in bacteria)
• Produces two identical
offspring
• Susceptible to diseases and
changing environments
• Genetic diversity
• Production of gametes to fuse
with another gamete (XX or
XY)
• Produces genetically different
offspring
• Ability to adapt to change in
environments
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Cellular Reproduction
Haploid
Diploid
• Refers to one set of
chromosomes (n)
• Humans have ___
chromosomes
• Haploid would be ____
• Fruit fly have ___
chromosomes
• Haploid would be ____
• Refers to two sets of
chromosomes (2n)
• Humans have ___
chromsomes
• Diploid would be ____
• Fruit fly have ___
chromosomes
• Diploid would be ____
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Cellular Reproduction
What are chromosomes?
• Chromosomes are rod-shaped structures
made up of DNA and proteins.
• Two chromatids make up a chromosome
• Centromeres are attachment points for two
chromatids and hold them together
• Chromatin are less tightly coiled DNA-protein
complex used to form chromosomes
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Confused yet?
chromatid
centromere
Condensed, duplicated chromosome
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Cellular Reproduction
9.1 Cellular Growth
The Cell Cycle
The main purpose of cell division
– to grow and heal certain
injuries.
 Cells reproduce by a cycle of growing and
dividing called the cell cycle.
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Cell cycle in three different stages
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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.
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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.
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9.1 Cellular Growth
The Second Stage of Interphase, S [Synthesis]
 The cell copies its DNA in preparation for
cell division.
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Cellular Reproduction
9.1 Cellular Growth
The Third Stage of Interphase, Gap2
 The cell continues to grow and prepares for
the division of its nucleus.
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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.
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9.2 Mitosis and Cytokinesis
 The nuclear
envelope begins
to disappear.
 Spindle fibers
attach to the sister
chromatids.
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9.2 Mitosis and Cytokinesis
Metaphase
 Sister chromatids
are pulled along the
spindle apparatus
towards the center.
 They line up in the
middle of the cell.
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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.
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9.2 Mitosis and Cytokinesis
 The sister chromatids
now become separate
chromosomes.
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9.2 Mitosis and Cytokinesis
Telophase
 Two new nuclear membranes begin to form
and the nucleoli reappear.
 The spindle apparatus disassembles.
 The pinching between the newly formed cells
(called a cleavage furrow) is an indication of
telophase.
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9.2 Mitosis and Cytokinesis
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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.
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9.2 Mitosis and Cytokinesis
 Division of two
IDENTICAL daughter
cells with the same
amount of
chromosomes (DNA).
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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.
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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.
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9.3 Cell Cycle Regulation
Causes of Cancer
 Mutations that cause problems in the
regulation of cell growth and division
 Various environmental factors can affect the
occurrence of cancer cells.