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Definition
| An imaginary structure located at a plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located |
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Definition
| Microtubles that do not attach to kinetochores, but interact with other nonkinetochore Microtubles from the opposite pole |
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Term
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Definition
this phase is the major period of cell growth during its
lifespan. During this stage new organelles are being synthesized, so the cell requires both
structural proteins and enzymes, resulting
in a great amount of protein synthesis and a high rate of metabolism
in the cell |
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Term
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Definition
| S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease |
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Definition
- A nuclear envelope encloses the nucleus.
-The nucleus contains one or more nucleoli
- Two centromeres have formed by duplication of a single chromosome.
- Chromosomes, duplicated in S phase, cannot be seen individually because they have not yet condensed |
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Definition
| Are regions in animal cells that organize the Microtubles of the spindle. Each centrosome contains two centrioles |
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Definition
- The chromatin fibers becomes more tightly coiled, condensing into discrete chromosomes observable with a light microscope.
- The nucleoli disappear
- Each duplicated chromosome appears as two identical sister chromatids joined at their centromeres, and in some species along their arms by cohesion.
- The mitotic spindle begins to form. It is composed of the centrosomes and the microtubles that extend from them. The radial arrays of shorter microtubles that extend from the centrosomes are called asters.
- The centrosomes move away from each other, propelled partly by lengthing microtubles between them. |
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Term
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Definition
- The nuclear envelope fragments
- The microtubles extending from each centrosome can now invade the nuclear area.
- The chromosomes have become even more condensed.
- Each of the two chromatids of each chromosome now has a kinetochore.
- Some microtubles attach to the kinetochores, becoming kinetochore microtubles, which jerk the chromosomes back and forth.
- Non kinetochore microtubles interact with those from the opposite pole of the spindle. |
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Term
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Definition
- The centrosomes are now at opposite poles of the cell.
- The chromosomes convene at the metaphase plate.
- For each chromosome, the kinetochores of the sister chromatids are attached to kinetochore microtubles coming from opposite poles
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Term
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Definition
- Anaphase is the shortest phase of mitosis, often lasting a few minutes.
- Anaphase begins when the cohesion proteins are cleaved. This allows the two sister chromatids of each pair to part suddenly. Each chromatid thus becomes a full fledged chromosome.
- The two daughter chromosomes begin moving toward opposite ends of the cell as their kinetochore microtubles shorten.
- The cell elongates as the nonkinetochore microtubles lengthen
- By the end of anaphase, the two ends of the cell have equivalent and complete
collections of chromosomes.
***separse is the name of the enzyme that cleaves the sister chromatids*** |
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Term
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Definition
- Two daughter nuclei from in the cell. Nuclear envelopes arise from the fragments of the parent cells nuclear envelope and other portions of the endomembrane system.
- Nucleoli reappear
- The chromosomes become less condensed.
- Any remaining spindle microtubles are depolymerized.
- Mitosis, the division of one nucleus into two genetically identical nuclei, is now complete. |
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Term
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Definition
- The division of the cytoplasm is usually well under way by late telophase, so the two daughter cells appear shortly after the end of mitosis.
- In animal cells, cytokinesis involves the formation of a cleavage furrow, which pinches the cell in two |
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Term
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Definition
| 1. The process of cytokinesis in animal cells, characterized by pinching the of the plasma membrane. 2. The succession of rapid cell divisions without significant growth during early embryonic development that converts the zygote to a ball of cells. |
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Definition
| The first sign of cleavage in an animal cell; a shallow groove around the cell in the cell surface near the old metaphase plate. ***on the cytoplasmic side of the furrow is a contractile ring of actin micro filaments associated with molecules of protein myosin. This interaction causes the actin microfilaments to contract, which begins to deepen the furrow until the cell splits. |
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Definition
| In plant cells, this is no cleavage furrow... Instead, the golgi apparatus sends vesicles to the middle of the cell, where they coalesce (bind/unite) to form the cell plate. |
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Definition
| Refers to the process of when a cell grows to double its size then divides to form two cells and to the asexual reproduction of a single celled eukaryote |
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Definition
| Site where the replication of a DNA molecule begins, consisting with a specific sequence of nucleotides. |
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Term
| cell cycle control system |
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Definition
| In the cell cycle, a checkpoint is a control point where to stop and go-ahead signals that regulate the cycle. **Three major checkpoints are found in the G1, G2, and M phases.** If the cell gets the go-ahead signal from the G1 phase, the rest of the phases will occur and the cell will divide. However, if the go ahead is not received, the cell will enter the G0 phase. |
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Term
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Definition
| In the cell cycle, a checkpoint is a control point where to stop and go-ahead signals that regulate the cycle. **Three major checkpoints are found in the G1, G2, and M phases.** If the cell gets the go-ahead signal from the G1 phase, the rest of the phases will occur and the cell will divide. However, if the go ahead is not received, the cell will enter the G0 phase. ***protein kinases give the go ahead signal in the G1 and G2 phase |
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Term
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Definition
| The phase the cell will enter if it does not receive the go ahead signal in the G1 phase, it is a non dividing state. **Most cells of the human body are actually in the G0 phase. **Cells in the G0 phase can return to the cell cycle by external cues. |
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Term
| Cyclin dependent Kinases (Cdks) |
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Definition
| A protein kinases that requires a cyclin (a protein that gets its name from its cyclically fluctuating concentration in the cell) to be attached to it. The activity of the Cdks rises and falls changes in the concentration of its cyclin. |
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Term
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Definition
| Maturation-promoting factor (also, M-Phase promoting factor)... a protein complex required for a cell to progress from late interphase to mitosis The active form consists of cyclin and a protein kinase. ****So a Cdk binds to a cyclin in the G2 phase (cyclin is protected for degradation in this phase), the Cdk is now a MPF... The MPF phosphorylates various proteins that contribute to mitosis... Once the cell enters anaphase, the cyclin is degraded, which ends the M phase. The cells then enter the G1 phase, the degradation of the cyclin continues and the Cdk is available to be used again. |
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Term
| Density dependent inhibition |
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Definition
| A phenomenon in which crowded cells stop dividing... No room for the new cells to grow |
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Term
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Definition
| To divide, they must be attached to a substratum (needs something to bind to... similar to how a house needs to be build on a solid foundation) |
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Definition
| Turns a normal cell into a cancer cell. |
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Term
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Definition
| The abnormal cells remain at the original site. Tend to not cause serious damage and can be completely removed by surgery |
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Definition
| Includes cells whose genetic and cellular changes enable them to spread to new tissues and impair the functions of one or more organs. An individual that has a malignant tumor is said to have cancer. |
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Definition
| The spread of cancer cell to locations distant from their original site |
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Definition
The continuity of life is based on reproduction of cells.
Functions in renewal, and repair, replacing cells that have died or have become damaged |
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Term
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Definition
| The life of a cell from the time it is first formed from a dividing parent cell until its own division into two daughter cells |
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Definition
| A cell endowment of DNA, it's genetic information. |
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Term
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Definition
DNA molecules packaged into structures
Get there name because they take up certain dyes used in microscopy. |
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Term
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Definition
The complex of DNA and proteins that makes up eukaryotic chromosomes.
When the cell is not dividing, chromatin exist in its disperse form, as a mass of very long, thin fibers that are not visible with a light microscope |
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Term
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Definition
Are joined copies of the original chromosome.
Two chromatids, each containing an identical DNA molecule, are initially attached all along their lengths by protein complexes called cohesions.
***For sister chromatids, it is called sister chromatid cohesion*** |
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Term
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Definition
Includes both the mitosis and cytokinesis.
Usually the shortest part of the cell cycle. |
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Term
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Definition
A region containing specific DNA sequences where the chromatid is attached most closely to its sister chromatid.
It's said to give the chromosome a "waist". |
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Term
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Definition
The division of the genetic material in the nucleus.
It is usually followed by cytokinesis.
Thus one cell has become two cell, both genetically identical to the parent cell.
Has five stages:
Prophase
Prometaphase
Metaphase
Anaphase
Telophase |
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Term
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Definition
Accounts for 90% of the cycle.
A cell that is about to divide grows and copies it's chromosomes in preparation of cell division.
Can be divided into sub-phases:
G1 phase (first gap)
S phase (synthesis)
G2 phase (second gap)
During all three sub-phases, a cell that will eventually divide grows by producing proteins and cytoplasmic organelles.
Chromosomes are only duplicated in the S phase.
So it short it, grows, synthesizes chromosomes, grows and then divides. |
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Term
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Definition
Begins to form in the cytoplasm during prophase.
It's structure consists of fibers made of microtubules and associated proteins.
When the spindle assembles, the other microtubules of the cytoskeleton partially disassemble, providing the material used to construct the spindle.
**The assembly of spindle microtubules starts at the Centrosome. |
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Term
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Definition
| A radial array of short microtubules, extends from each Centrosome. |
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Term
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Definition
A structure of proteins associated with specific sections of chromosomal DNA at each centromere.
Spindle microtubules attach to the kinetochores, these are called kinetochore microtubules. |
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