Zoology 101 - Cancer
Terms
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- What are the 3 checkpoints?
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G1 checkpoint
G2 checkpoint
Metaphase checkpoint - G1 checkpoint
- Make sure cells have the right size, nutrients, growth factors to go from G1 to G2 in cell cycle
- G2 checkpoint
- Make sure cells are the right size, have DNA replicated before starting prophase of mitosis
- Metaphase checkpoint
- Makes sure all chromosomes are attached to microtubules of spindle before anaphase of mitosis begins
- What are proto-oncogenes? How do oncogenes differ from them?
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Genes coding for proteins to regulate the cell cycle
Oncogenes are mutated proto-oncogenes that encourage the cell to undergo mitosis more rapidly - What are the 4 genetic changes that cause proto-oncogenes to become oncogenes?
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Proto-oncogene moved to a new place nexte to a promoter that never turns off. Proteins that enourage mitosis are made constantly --> Cell never stops dividing
Gene amplification: extra copies of proto-oncogene inserted on DNA, make extra proteins encourage mitosis --> increased cell division
Point mutations in promoter region of oncogene make promoter always in "on" mode
Ponit mutation in gene itself makes a "hyperactive" protein that enourages mitosis to happen more often - What do tumor supressors do?
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Detect and repair DNA damage or shut down cell division
If mutated: cell checkpoints overidden/cell won't stop dividing - P53
- helps cell decide whether to repair damaged DNA or commit cell suicide
- BRCA-2
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encodes protein that helps repair damaged DNA at G2
Ovarian and breast cancers - What are the two properties of normal cells that are lacking in cancerous cells
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Contact inhibition
Anchorage dependence - Contact inhibition
- prevent cell division if doing so would cause piling up
- Anchorage dependence
- requre contact with other cells in order to attach
- A tumor can progress through various stages, with additional mutation. What are the 3 stages
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Benign
Malignant
Metastasis - Benign
- tumor isolated to certain area
- Malignant
- Spreads to other tissues
- Metastasis
- Further spread by lymph system
- What is chemotherapy?
- injection of chemicals into bloodstream to kill rapidly dividing cells (prevent mitosis)
- What is radiation therapy?
- Use high electron particles to injure/destroy cells by damagingthe DNA; cells can't grow/divide
- What are angiogensis inhibitors?
- Keeps blood vessels from reaching tumor so its nutrient supply is cut off and abnormal cells can't get travel to other parts of body (metastasize) through blood stream
- How migh antisense RNA help treat cancer?
- Can bind to mRNA trascribed from an oncogene, so it can't be translated into a protein that encourages rapid mitosis