Download Cellular Reproduction

Cellular Reproduction
Mitosis
Cell reproduction occurs when parent
cells divide. Two new daughter cells
arise from each parent cell.
The production of new cells serves
several functions
• Early Development
1. GROWTH: Increase the number of cells
2. SPECIALIZE: Production of the many different cell
types that will make up the mature organism
• After Full Development
1. Repair damage tissues
2. Replace cells that are
lost from the outer surface
3. Resist disease
Small cells are better than large cells.
There is more surface area for the cell
membrane to meet the cell’s needs
Cells stop growing or reproduce before
they reach the point of:
• Starving because of a
lack of nutrients
• Being poisoned
because of waste
buildup
Mitosis
The process by which chromosomes
are duplicated and distributed to
daughter nuclei
Each daughter cell nucleus carries the
same set of genetic information as the
parent nucleus
Interphase and Mitosis make up the
cell cycle
Mitosis is a series of “phases”
where the end of one phase blends
with the beginning of the next
Interphase (NOT part of mitosis)
• The in-between phase where chromosomes
replicate
• Interphase begins when cell reproduction is
completed.
• Interphase is a non-reproducing phase in
which the cell spends most of its life
Early Interphase (still NOT mitosis)
• New parts such as ribosomes and
mitochondria are produced
– Animal cells: new centrioles
– Plant cells: new chloroplasts
Interphase
• Look for
a. Complete nuclear membrane
b. Chromosomes NOT visible
Nuclear membrane
chromatin
Interphase
Prophase
• Chromosome become dark and thick
• Look for:
a. Nuclear membrane disappearing
b. Chromosomes look like dark, thick
threads
Nuclear Membrane
Chromosome threads
Mitosis - Prophase
Prometaphase
• Chromosomes move to the equator
• Look for:
a. Nuclear membrane is gone
b. Paired chromosomes
attached with centromeres
move toward the equator
Metaphase
• Chromosomes line up and attach to spindle
fibers
• Look for: chromosomes lined up at the
equator
Mitosis - Metaphase
Anaphase
• Chromosomes (chromatids) move to the poles
• Look for: chromatids pulling apart at the
centromeres
Mitosis - Anaphase
Telophase
• The cell begins to divide and 2 new daughter cells
develop. The nuclear membrane starts to reappear.
• Look for:
a. (animal) cleavage furrow
b. (plant) equitorial plate
Mitosis – Late Telophase
Plant Cell – equatorial plate
forming
Animal Cell – cleavage furrow forming
Cytokinesis
• The cytoplasm splits
• Two new daughter cells are formed
• The resulting cells enter back into Interphase
Daughter Cells
Mitosis
Prophase
Telophase
Interphase
Interphase
Telophase
Anaphase
Prophase
Interphase
Metaphase
Prophase
It is estimated that 25 million cell
division occur every second in the
human body
Different types of cells divide at
different rates
• Red Blood Cell form in bone marrow and
reproduce rapidly to keep up with the need
for new cells
• Muscle and Nerve cells never reproduce once
they mature
• Human Liver Cells divide only when new cells
are needed to repair wounds.
If one type of cell grows too rapidly,
the normal organization of the
organism is disrupted.
Cancer is one kind of
disruption. When
there is a rapid,
uncontrolled division
of one kind of cell, it
invades and disrupts
cells in other tissue.
Genetic Uniformity = Mitosis
The genes in every daughter cell are identical to
the genes in the parent cell
******BODY CELLS