Cell Reproduction
QSR #6??
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1. _________ is the process by
which cells divide to make more
cells.
2. Your _______ cells divide most
often while your ______ cells almost
never divide.
3. In eukaryotic cells, chromosomes
are found in the _______, but in
prokaryotic cells they are found in
the ____________.
Cell Reproduction
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Cell division is the process by which
cells reproduce
Chromosomes: rod-shaped
structures made of DNA and proteins
Chromatids
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One single strand
of the chromosome
Held together by a
centromere
Cell Cycle
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Sequence of growth and division of a
cell – the life cycle of a cell
• Apoptosis: cellular death
• Figure2.14 – In the embryo, fingers and
toes are carved from webbed
structures. In syndactyly, normal
apoptosis, fails to carve the digits and
webbing occurs
CELL CYCLE
A. Interphase
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1. Resting phase because it is not dividing
but it can be getting ready for division
2. performing everyday, normal functions
3. Can be divided into 3 stages
• G1
•S
• G2
B. G1 phase (Gap 1)
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1.Growth phase
2.Grows rapidly
3.Carries out routine functions
C. S phase
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Synthesis of DNA
DNA is copied
D. G2 phase (Gap 2)
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1.Growth and Prep for Mitosis
2.organelles replicates
(Doubling everything to prepare for
mitosis)
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Cells divide at different rates:
Cell type
Approximate life span
• Skin cells
2 weeks
• Red blood cell
4 months
• Liver cell
300-500 days
• Intestinal cells
4-5 days
• Muscle/other cells
16 years
• Brain cells
maybe never
• ++++++++++++++++++++++++
Mitosis
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Process in which the nucleus of a cell
divides into two nuclei, each with the
same kind of chromosomes
Interphase
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Chromosomes are replicated
Chromosomes appear as threadlike
coils (chromatin) at the start, but
each chromosome and its copy
(sister chromosome) change to sister
chromatids at the end of this phase
• ***Remember: sister chromatids are
held together by a centromere.
The Stages of the cell cycle
" Intellegent People Meet At Three
O'Clock"
Prophase
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Mitosis begins in this phase
Centrioles (poles) appear and begin to
move to opposite ends of cell.
Spindle fibers form between the poles
CHROMATIN condenses (coils up) into
CHROMOSOMES
The nuclear envelope starts to break up
the Nucleolus disappears
Metaphase
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Chromatids or pairs of chromosomes
attach to the spindle fibers
the Chromosomes line up at the
“Middle” of the cell
Anaphase
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Chromatids (or pairs of
chromosomes) separate and begin to
move to opposite ends of the cell
Centromere divides
Telophase
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Two new nuclei form
Chromosomes appear as chromatin
(threads rather than rods)
Nuclear envelope & nucleolus
reforms
Cytokinesis
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Division of the cytoplasm
• Cell membrane moves inward to create
two daughter cells – each with its
own nucleus, identical chromosomes,
and a total of 46 chromosomes each
• Microscope: fish blastodisc (white fish)
mitosis, onion tip mitosis, ascaris
mitosis (parasite – intestinal
roundworm)
What phase and Why?
What phase and Why?
What phase and Why?
What phase and Why?
What phase and Why?
Animated mitosis
Mitosis, Mitosis
Amelia Arellano
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Mitosis, Mitosis divided into four
stages. Prophase, Metaphase,
Anaphase, and Telephase. Prophase
Prophase, Nucleus breaks down
Metaphase, Metaphase Chromosomes
line up in the center. Anaphase,
Anaphase chromosomes moving to
the opposite poles. Telophase,
Telophase envelop forms And the
spindle fiber begin to disappear
Results of Mitosis
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Cells
Tissues
• muscle
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Organs
• stomach
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Organ system
• Digestive system
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Organism
Stem cells
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Undifferentiated/ blank cell
Can be developed into a variety of
different cells
Ex: embryonic stem cell can give rise to
almost any cell
Ex: Adult stem cells can give rise to
related cells
Why is stem cell research so important?
Cell Differentiation
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Cells become specialized to perform
specific functions…liver cells, skin
cells, etc.
Is based on location in an embryo
• Outer– skin, brain, spinal cord
• Middle– bones, muscles, kidneys
• Inner– internal organs (pancreas,
stomach, etc.)
Asexual Reproduction
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Creation of an offspring with only one parent
Ex: Binary Fission
• a form of mitosis
• – division into 2 equal parts
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**** (done in prokaryotic cells) ****
Genetically identical to parent
Ex: bacteria, some plants (stem cutting), sea star
How is this different from sexual reproduction?
######################
QSR #8
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1. Fill in the blanks to make the correct order:
cells, ______, ______,
systems, _________.
2. _____ cells are undifferentiated meaning they
____________ and can become other types of
cells.
3. Cell differentiation depends on the location of
the cells inside the ______. If they are in the
outer layer they can become ________, middle
layer________, inner layer________.
4. How are embryonic stem cells different from
adult stem cells?
Cancer
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Cancer
• Uncontrolled Mitosis/Cell Division
• Enzymes (proteins) monitor a cell’s
progress from phase to phase
Cancer
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Caused by damaged genes
• Cancerous (malignant) cells form
masses of tissue
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Tumors
• Deprive normal cells of nutrients
• Spread throughout the body
 Metastasis (cancer cells break away, get into
blood stream, and spread)
Cause of Cancers
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1. Environmental factors (Carcinogens) – damage
genes
• Cigarette smoke, air pollutants, UV radiation
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2. Genetic
3. Viral Infections
4. Different types of cancers in different parts of
the world
• Breast cancer
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High US
Low Japan
• Stomach cancer
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High in China
Low in US
Cancer Prevention
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Diet
• Low in fat
• High in fiber
Cancer Prevention
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Healthy Exercise and NO TOBACCO
products!!!!
Vitamins and mineral
• Yellow
• Orange
•A
•C
•E
• Ca