Download Mitosis and Cytokinesis - Mr. Allen`s Biology Class

Mitosis and
Cytokinesis
5.2
EQ: What are the stages of mitosis
and what is its role in the formation of
new cells?
A chromosome is a long continuous thread of
numerous genes.
Your cells have 46 chromosomes each (23 from mom
and 23 from dad)
Histones are proteins associated with chromosomes.
They help to condense DNA.
Chromatin is the combination of loose DNA and
proteins.
One half of a duplicated chromosome is called a
chromatid.
Sister chromatids are held together at the
centromere.
The ends of DNA molecules form structures called
telomeres.
Telomeres prevent chromosomes from attaching to
each other.
Mitosis divides a cell’s nucleus into 2 genetically identical
nuclei. It ONLY occurs in somatic cells.
A somatic cell is any cell that does not form gametes.
A gamete is a sex cell (sperm or egg).
Mitosis has 4 stages – Prophase, Metaphase,
Anaphase, and Telophase.
1) Prophase – chromatic condenses into tightly coiled
chromosomes, nuclear envelop breaks down,
2) metaphase – chromosomes are aligned along the
cell equator.
3) anaphase – chromatids separate to opposite sides
of the cell.
4) telophase – nuclear membranes begin to form;
chromatids uncoil.
Cytokinesis – cytoplasm is divided. Each new cells has
a complete copy of identical DNA.
Regulation of the Cell
5.3
Essential Question (EQ): How is cell
division regulated and what happens
when this regulation is lost?
Growth factors are a broad group of proteins that
stimulate cell division.
Apoptosis is programmed cell death.
Cancer – disease characterized by uncontrolled cell
division.
Cancer is the result of a breakdown of cell cycle
regulation.
Cancer cells formed disorganized clumps called
tumors.
Tumors are either benign – remains clustered and is
relatively harmless; or malignant – likely to spread to
other parts of the body.
Why are cancer cells harmful?
Because cancer cell do not perform their intended
function…
Carcinogens – substances known to promote the
development of cancer cells.
Standard cancer treatment involves often involves,
radiation, chemotherapy, and sometimes surgical
removal of a tumor.
Multicellular Life
5.5
Essential Question (EQ): How
are cell’s organized to
produce a multicellular
organism?
Uni means “one”.
Examples: universe, uno, unicycle, unibrow, unicorn, etc.
Unicellular organisms have only one cell.
Examples: Bacteria, Algae, amoeba
multi means “many”.
Examples: multiply, multiple, multiyear, etc.
multicellular organisms have many cells.
Examples: Kate Beckensale, David Beckham, plants,
spiders, sponges, whales, and … YOU!
How do we use one cell to make an entire
multicellular organisms?
Tissue is a group of cells that work together to
perform a similar function.
Groups of tissues that work together to form a similar
function are known as organs.
Organs that carry out a similar function are known as
organs systems.
How do you go from one cell to the many types of
cells found in different organs???
Cell differentiation is the process by which
unspecialized cells develop into their mature forms
and functions.
What the heck does that mean, Mr. Allen?!
Most of he cells in your body have a full set of DNA.
However, the differentiated cells only use SOME of
the DNA to function.
Example: a muscle cell only uses the genes from DNA
that it needs to contract and relax even though it has
THOUSANDS of genes.
What are undifferentiated cells called?
Undifferentiated cells that can develop into
specialized cells are known as stem cells.
Embryonic stem cells have given many people hope
that some devastating diseases might be curable in
the near future.