Ch3 How cells die Flashcards
HeLa cells
- She died in
-1951
___ ___ is the ultimate goala of rad therapy
- Cell death
DNA damage responce determins (2)
- Sensitivity of cells to die
- Type and timing of cell death
Apoptosis is
an important cellular defense
against cancer development and loss of
apoptotic sensitivity is recognized as an
essential hallmark of cancer
Participants in apoptotic pathways
- Sensors
- Effectors
- make decision to initaite apoptosis
- Carry out the decision
Apoptosis controlled by gene __ and is ___ in cancer cells
- p53
- Altered
All types of cell self kill (4)
- Autophagy
- Necrosis
- Senescence
- Mitotic catastrophe
What is Autophagy
When cells digest part of their own cytoplasm to generate energy (tumor supressor)
What is Necrosis
- Characterized by (4)
- Occurs after (3)
- AKA
- Swelling, membrane deformation, organelle breakdown, lysomes
- Infection, inflammation, ischemia
- “death by injury”
What is Senescence
- What is it
- Caused by
- Cells losing the ability to divide overtime (aging process)
- cell cycle inhibitor protein
Miotic catastrophe
- Happens when
- Occurs after
- Leads to (type)
- Cells enter miosis with unresolved DNA
- Irradiation
- Death by apoptosis, because cell cant seperate and replicate genetic material
Early cell death
- cells die within ___ of irradiation
- AKA
- Most common cells that die early
- Hours
- Interphase death
- Lymphocytes, Spermatagonia, Small intestines, developing embryos
Late cell death
- Cells dont die until
- ___ inhibit apoptosis
- ___ ___ occurs after DNA damage is too extreme (AKA)
- After mitosis
- mutations in cell cycle
- Miotic castrophe (Reproductive failure)
Puck and Marcus
- Observed that
- Identified 3 distict dose dependant events that are
- reproducibility of cells after different doses of radiation
- Division delay, Interphase death, reproductive failure
During division delay cells are
stunted and do not proceed through mitosis as usual
Interphase death cells die before
They divide
Reproductive failure cell dies when attempting ___
mitosis
Division delay - Miotic index is the
Ratio of total number of cells in mitosis at any one, time to the total number of cells in the population
Division delay - Miotic overshoot
- Represents cells
- Includes cells that
- Ability to overcome irradiation
- Are on a regular cycle or have been delayed from mitosis
Division delay - Rationale
- A ___ involved in division is altered by ___
- ___ is necessary for mitosis and are not ___
- ___ synthesis does not progress at the same rate post-irradiation
- Chemical, irradiation
- Proteins, synthesized
- DNA
Cell cycle Divison Delay
- Dependant on
- Function of dose affects
- Occurs a stage ___ and before ___ ___
- Dose
- mitotic index and length of delay
- G2, DNA synthesis
Division delay
- Approximate delay ___min/cGy
- ___ is the most important at ___min/cGY
- 1 min
- 1.4 min
Interphase death
- Death before
- Lowers doses on ___ cells
- Higher doses on ___ cells
- Cell is destroyed but organelles remain
intact aka
- cell enters mitosis
- Radiosensitive cells
- Radioresistant cells
- Apoptosis
Radiosensitive cells characteristics (2)
- Rapidly dividing
- Undifferentiated cells
Radioresistant cells characteristics (2)
- Nondividing
- Differentaited
Reproductive failure
- Decreases percentage off cell
- Higher doses
- What theory begins
- capable of reproduction
- Affect greater number of cells
- Target
Cellular Response to Radiation
- Division delay dose
- Reproductive failure dose
- Interphase death
- .8 Gy/83 Rad
- 3 Gy/300 rad
- 10 Gy/1000 Rad
