Download Cell Cycle & Mitosis

Cell Cycle & Mitosis
Biology
Chromosomes
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The growth and development of your cells
are carefully controlled by a set of
instructions found inside the cell nucleus.
These instructions are encoded in DNA and
determines that you are human.
When cells divide, this material is tightly
compacted, creating bodies of DNA and
protein called chromosomes.
Chromatids
Each chromosome has two identical
rods. One is an exact copy of the
other. Each identical rod is called a
chromatid.
 The two chromatids are held together
by a centromere.
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Chromosome Number
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A set of chromosomes is called a karyotype.
Every person has 46 chromosomes, or 23
pairs of chromosomes in a karyotype.
When a human cell contains 23 pairs of
chromosomes, it is called diploid.
Gametes (eggs and sperm) only contain
one copy of each chromosome, they are
called haploid.
Sex Chromosomes
Sex chromosomes determine whether
or not you are male or female.
 They are designated as x or y.
 If you are female, you have two x
chromosomes.
 If you are male, you have one x and
one y chromosome.
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Mitosis and Cell Division
When a cell reaches a certain size, it
will either stop growing or divide.
 If a cell is to divide and produce two
new healthy cells, it must first copy
the genetic information in order to
function.
Stage 1: Interphase
Interphase is the period
before cell division begins.
 During interphase, the cell
grows, makes a copy of its
DNA, makes copies of the
organelles, and gets ready
to divide.
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Stage 2: Mitosis
Eukaryotic cells divide via Mitosis.
 Mitosis is the process by which the
nucleus of a eukaryotic cell divides to
form two nuclei, each containing a
complete set of the cell’s
chromosomes.
 Mitosis can be broken down into four
distinct phases: prophase,
metaphase, anaphase, and telophase.
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Prophase
Prophase is the first and
longest phase of mitosis.
 The chromatin condenses
into chromosomes.
 The centrioles separate,
and a spindle begins to
form.
 The nuclear envelope
breaks down.
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Metaphase
The second phase of
mitosis, often lasts only a
few minutes.
 Chromosomes line up
across the middle of the
cell.
 Spindle fibers begin to
form.
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Anaphase
Third phase of mitosis.
 Chromosomes begin to pull apart and
separate to opposite ends of the cell.
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Telophase
The fourth and final phase of mitosis.
 A nuclear membrane re-forms around each
cluster of chromosomes.
 Mitosis is complete.
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The Cell Cycle
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The cycle of growth and division.
Mitosis is followed by cell division, also
called cytokinesis.
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http://www.cellsalive.com/mitosis.htm
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Cancer and Mutations
Cancer arises from a mutated gene
that causes a faulty cell cycle.
 Cancer is a term used to describe a
disease characterized by uncontrolled
cell division and growth.
 The result is a clump of cells called a
tumor.
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