Gyan Prayaga
Mrs. Wareham
AP Biology
30 January 2014
Chapter 12 ID Terms
ID Term
Location/Structure
Additional Info
(if applicable)
Binary
Occurs in most
Binary fission is a type of asexual
Fission
prokaryotes and some
reproduction which involves the dividing
single-celled
of a cell into two identical cells after the
eukaryotes.
genetic material is replicated. It is the
most common form of reproduction in
prokaryotes, although it is also used in
some primitive eukaryotes.
Binary fission in a prokaryotic organism
Chromosom
A single strand of
Chromosomes are organized structures of
es
coiled DNA composed
genetic material (DNA and RNA) and
of many nucleotides,
proteins which are found in both
found in the
eukaryotic and prokaryotic cells.
nucleotide of a
Chromosomes are made up of DNA and
eukaryotic cell or
protein combined together to form a
coiled around proteins
chromatin.
dispersed around a
Somatic Cell
prokaryotic cell.
Rendering of a chromosome inside a cell
Found in the organs,
A somatic cell is any cell in an organism
skin, bones, blood, and except for the sex cells (also known as
connective tissue of an
reproductive cells). These cells have twice
organism. These are
the number of chromosomes as
the non-reproductive
reproductive cells and are diploid, as
counterparts of sex
opposed to haploid gamete cells. Somatic
cells.
cells replicate through mitosis, as
opposed to sex cells which reproduce
through meiosis.
Diagram showing the cell cycle of a
somatic cell
Gamete
The reproductive
Unlike diploid somatic cells which have a
counterpart of somatic
full set of chromosomes (two sets of 23
cells, these sex cells
chromosomes), gametes are haploid and
are found in the
only have a single pair of chromosomes.
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reproductive tracts of
This is because one gamete will fuse to
organisms.
another gamete (in another parent
organism) in order to produce a child.
Sexual reproduction in humans
Chromatid
A chromatid is a copy
A chromatid is one of two identical
of a chromosome,
chromosomes which is joined to another
which is found in the
chromatid during the process of nuclear
cell nucleus and is
division (either meiosis or mitosis).
composed of a long
Chromatids are generally identical (in
string of genetic
most situations), although they can be
material.
heterozygous if there are mutations,
which lead to daughter cells which are
not identical.
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Kinetochore
Occurs in the cell
Kinetochores are protein structures on
nucleus. A protein
chromatids (half of two identical
structure located on
chromosomes during cell division) where
the chromatids (half of
spindle fibers attach to pull apart the
two identical
sister chromosomes. The kinetochore is
chromosomes) which
located on the centromere of eukaryotic
divide during cell
cell chromosomes and connects to
division.
microtubule spindle fibers.
Microtubules (green), chromosomes (blue)
and kinetochores (pink)
Chromatin
Chromatin is the
Chromatin wraps around histone proteins
building block of
to form nucleosomes, which allow for
chromosomes, which is genetic material to be transferred. The
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composed of protein
figure below shows how chromosomes
and DNA fibers. It is
are condensed from chromatin, which are
composed of long
long strands of genetic material.
strands of genetic
material.
Mitosis
Mitosis is a form of
Mitosis is made up of a number of steps -
cell division in which a
Interphase, Prophase, Prometaphase,
cell divides into two
Metaphase, Anaphase, Telophase and
genetically identical
Cytokinesis. Mitosis is important because
“daughter” cells. It
it aids in development and growth, cell
takes place in the
replacement, regeneration, and asexual
nuclear envelope of
reproduction in organisms.
eukaryotic cells.
Diagram showing the various steps in
mitosis
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Interphase
Interphase is a stage
Interphase is the stage which takes up the
in mitosis which takes
most time in mitosis, involving the
place in the nuclear
growth, synthesis, and preparation for
envelope of the cell.
mitotic phase. There is growth in all three
of these stages.
Illustration of interphase
Checkpoint
Checkpoints regulate
Intra and extracellular signals allow cells
cell division in the
to move past each checkpoint. We don’t
nuclear envelope of
know exactly what is going on in the
the cell in the
signal transduction passway. There are
organism.
checks at the three stages in the
Interphase - G1, G2, and M. Failure to
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pass the checkpoint will result in the
suspension of that stage.
A visual explanation of cell cycle
checkpoints
Prophase
Prophase is a stage of
Prophase is a stage of the cell dividing
mitosis which takes
process mitosis consisting of the
place in the nuclear
condensing of chromatin into two rod-
envelope of the cell,
shaped chromosomes. This allows the
like the other stages.
chromatin to become visible. After the
interphase, prophase is the first true step
of mitosis.
Mitotic
The mitotic spindle
The mitotic spindle is a subcellular
Spindle
(also known as the
structure - which aggregates microtubules
spindle apparatus) is a
during cell division and keeps the two
structure which
sister chromosomes separated. These
separates
spindle fibers form at opposite poles (the
chromosomes during
two ends) of the cell’s nuclear envelope
cell division. It occurs
and keep it separated.
in the nuclear
envelope of the cell.
Diagram showing the mitotic spindle
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Prometaphas Prometaphase is the
In prometaphase, the nuclear membrane
e
stage which follows
breaks apart into numerous "membrane
prophase and
vesicles", and the chromosomes inside
precedes metaphase.
form protein structures called
Of course, it is a stage
kinetochores. Kinetochore microtubules
of mitosis and
which emerge from the centrosomes at
therefore occurs in the
the poles of the spindle reach the
nuclear envelope of
chromosomes and attach to the
the cell.
kinetochores. This causes the
chromosomes to get agitated and makes
contact with the opposite pole.
Metaphase
Metaphase follows
Metaphase is the next stage after
prometaphase and
prometaphase, and involves the “lining
also occurs in the
up” of chromosomes along the imaginary
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nuclear envelope.
metaphase plate. In metaphase, the
centromeres of the chromosomes
converge along the metaphase plate,
which is an imaginary line somewhat like
the equator - equidistant from the two
centrosome poles.
Diagram showing metaphase
Metaphase
The metaphase plate is The metaphase plate is an imaginary line
plate
an imaginary line
which is formed during the stage of
equidistant from the
metaphase in mitosis. The line is
two centrosome poles,
equidistant from the two centrosome
which is found in the
poles - somewhat like an equator.
metaphase stage of
Anaphase
mitosis in the nuclear
This diagram shows metaphase and the
envelope of the cell.
metaphase plate in the center
Anaphase is the next
In anaphase, the chromosomes are split
stage of mitosis, which
into two sister chromatids. This is
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follows metaphase. In
illustrated in the diagram below. The
anaphase, the
chromosomes break at the centromeres
chromosomes are split
(the point of crossing over) and move to
and the sister
opposite sides of the cell.
chromatids move to
opposite sides of the
The diagram below shows the
cell. Like metaphase,
occurrences in the anaphase stage.
anaphase also occurs
in the nuclear
envelope of the cell.
Telophase
Telophase is the final
In telophase, the final stage of mitosis,
stage of mitosis, which
the nuclear membrane reforms as the
occurs in the nuclear
chromosomes unravel into chromatin. In
envelope of the cell
this stage, microfilaments from cleavage
during cell division.
furrow form as the chromosomes unravel.
This stage is the precursor to cytokinesis.
Cytokinesis
Cytokinesis is
In cytokinesis, the full division into two
essentially also the
separate identical daughter cells takes
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final stage of mitosis,
place This concludes the process of
which occurs in the
mitosis and creates two identical cells
nuclear envelope of
which will complete the reproduction
the cell during cell
process. Each cell has gone through the
division.
process to create two more copies, and
this cycle will continue.
Diagram of cytokinesis
Transformati
Transformation occurs
Transformation involves the conversion of
on
when cell transform
anormal cell into a cancerous cell. This
into cancer cells. This
leads to the creation of cancer in the
can happen anywhere.
form of a tumor, which can be very
damaging to an organism’s health.
A diagram of the transformation process
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Tumor
A cancerous tumor can Tumors (cancerous tumors) occur when
be located anywhere
there is a mistake in replication and a
in an organism, and
normal cell transforms into a cancerous
occurs when there is a
cell. These cancerous cells are unaffected
mutation or mistake in
by internal/external regulation and
cell replication.
checkpoints and are generally very
resilient. They are also immortal and can
be either benign or malignant (malignant
spreads throughout the entire body and
is much worse from a medical treatment
standpoint).
An image of a cancer cell
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Metastasis
Metastasis, like the
Metastasis is the conversion of non-
two previous concepts,
cancerous cells to cancer cells, involving
is related to cancer
the spread of a tumor throughout an
and the spread of
organism. This results in the proliferation
cancer and therefore
of cancer through either a part of the
can occur practically
organism or the entire organism.
anywhere in an
organism. Cell
The process of metastasis
replication is not
restricted to a certain
body part, so it can
easily spread
anywhere.
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