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Unit 6 - Coggle Diagram
Unit 6
Microscopic Helpers
Tumor Suppressor Genes
They control the process of cell growth and cell death, they can also suppress tumor development
When mutated, they can lead to tumor growth and formation
Both copies of the gene need to be mutated in order to cause a change in cell growth and can lead to tumor formation and growth, that is why it is called “recessive”
Tumor suppressor mutations are acquired, usually from old age and/or environmental exposures
Tumor suppressor mutations are also inherited, if inherited all cells only have one non-mutated suppressor gene
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DNA Repair Genes
DNA repair requires both genes to be mutated in order to begin to form tumor, so they are called “recessive”
Mutations in DNA repair gene can be acquired from aging or environmental factors or it can also be inherited
If mutated, DNA would remain mismatched and eros would occur, these errors could impact tumor suppressor and proto oncogenes
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Cyclins and CDKs
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The CDK-cyclin bond at the beginning of the phase, when it begins to weaken and they start to break apart, it signals the cell to move onto the next phase
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If a cell does not pass the checkpoint, the cdk and cyclin levels can remain higher and the process either kills the cell, or for cancer the cell spins out of control
Cell Cycle
Inter phase
Gap 1
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DNA and cell resources are checked by TP53, mainly cell growth, proteins, and organelles
Once the Checkpoint is passed, the G1 cyclin binds to CDK and they phosphorylate and bind to a phosphate, they then connect to a cell and transfer the phosphate and power the cell through to the next phase
Synthesis
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There is no checkpoint for synthesis, so the cell remains in synthesis until cyclins and cdks move it to G2.
Gap 2
DNA has been duplicated and the cell begins producing microtubules and other proteins necessary for cell division
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Mitosis
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Metaphase
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Microtubule depolymerisation causes the spindle fibers to shorten and be able to pull the sister chromatids and align them along the center of the cell
Anaphase
Continued contraction of the spindle fibers which causes the sister chromatids to separate and be pulled to the separate poles of the cell
Once separated, the chromatids are considered their own chromosomes
Telophase
Once the chromosomes reach the opposite poles of the cell, they spindle fibers dissolve
Chromosomes decondense, they reform into the chromatin
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Processes
Apoptosis
The cell shrinks down and is broken into pieces by a macrophage, the parts can be recycled for another cell
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When DNA is found to be damaged or there is a problem with the cell, it is marked and sent to go through programmed cell death
Hayflick Limit
The enzyme called telomerase is responsible for fixing telomeres and is commonly over active in cancer cells
Telomeres, on the ends of the sister chromatids, grow shorter with each division which helps to keep track of the number of divisions
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