Apoptosis Flashcards
Cell Cycle Phases
Interphase
G1
First gap phase
Cells grow in size, synthesize RNA and proteins, enter the cell cycle by reaching a point in G1 known as START, after that the cells are committed to cell division
Cell Cycle Phases
Interphase
S Phase
Active Replication of DNA
Cell Cycle Phases
Interphase
G2 Phase
Rapid cell growth, protein synthesis, getting ready for cell division. (Not necessary for entering M phase)
Cell Cycle Phases
M Phase
Prophase, metaphase, anaphase, telophase, cytokinesis
Prophase
- Nuclear envelope retracts into ER
- Golgi membranes break down into vesicles
- Kinetochore assembles at each centromere
- Mitotic spindle attaches to each chromosome’s kinetochore
- Chromosomes condense
Metaphase
- Chromosomes align on the equator
- Chromosomes most condensed
Anaphase
-Sister chromatids separate
Telophase
- Mitotic spindle disassembles
- Chromosomes decondense
- Nuclear Envelope Re-forms
Cytokinesis
Physical division of cytoplasm
Checkpoints of cell cycle
- G1/S phase boundary
- S phase
- G2/M phase boundary
Apoptosis
Programmed cell death.
An organized process that signals cells to self destruct for cell renewal or to control aberrant cell growth. Controls the orderly death of damaged cells
Causes of apoptosis
Inducers:
- Growth factor withdrawal
- Ionizing radiation
- CA2+ influx
- Tumor necrosis factor
- Viral infection
- Glucocorticoids
Apoptosis Regulation
Intrinsic pathway: activated by developmental cues, severe cell stress (DNA damage)
Extrinsic pathway: activated by pro-apoptotic ligand binding to key functional pro-apoptotic receptor
Propidium Iodide use to study apoptosis
Red fluorescent dye
- Nucleic acid binding dye
- Impermeant to live
- Shows dead cells in red
Annexin V use to study apoptosis
- human anticoagulant
- high affinity for PS
- can be labeled with fluorophore or biotin
- Can be detected in apoptotic cells by binding to PS exposed on the outer leaflet
