Module 11: Apoptosis Flashcards
What is the significance of apoptosis? (1)
Allows for the human to develop by removing cells.
What assay is used to observe apoptotic cells? (1)
What protein used in this assay? (1)
What does this assay detect specifically? (1)
TUNEL assay.
Fluorescently-labeled dUTP.
The DNA breaks/fragments that are the result of apoptosis in cells.
What induces apoptosis? (1)
Increase in thyroid hormone in the blood.
What causes neural apoptosis during neural development and what cells are affected? (2)
Half of the neurons will undergo apoptosis— specifically the ones that have not formed synaptic connections/ connections to the target cells, or the faulty ones.
What neurodegenerative disorders can result from irregular apoptosis and what are their effects? (3+3)
What other conditions arise from inappropriate cell death? (1)
Alzheimer’s— neurons in hippocampus and cerebral cortex die.
Huntington’s— neurons in striatum die.
Parkinson’s— neurons in substantia nigra region die.
Duchenne Muscular Dystrophy— muscular degeneration.
Describe the two ways cells can die. (2)
- Necrosis: agent damages the cell’s exterior; cell swells and contents are released into surrounding tissues— results in infection.
- Apoptosis: regulated cell death
Describe the steps of the apoptotic pathway. (3)
- Cell execution
- Engulfment.
- Clearance.
Describe what occurs in the cell during apoptosis to: (5)
- chromatin
- nuclear envelope
- contents of nucleus/DNA
- proteins
- cytoplasm
Chromatin compacts and becomes dense.
Nuclear envelope breaks down.
Contents of nucleus is fragmented; DNA is broken down.
Proteins are degraded.
Cytoplasm undergoes condensation as cellular components aggregate.
What is the result of the ced-1 gene mutation? (1)
What is the result of the ced-3 gene mutation? (1)
Cells undergo apoptosis, but are not phagocytosed.
No apoptosis occurs.
What are homologs of the EGL-1 protein? (2)
What is the homolog of the CED-9 genes and where is it found in human cells? What does it control? (2)
What is the homolog for the CED- 3 and 4 protein? What is its function? (1)
Bid and Bim.
Bcl-2; found on mitochondrial membrane. Bax and Bak.
Caspase complex; targets many different proteins for degradation.
What is difference between the loss of function mutation CED 3/4 vs CED-9? (3)
Former prevents apoptosis, latter inhibits apoptosis by inhibiting Caspase holoenzyme so all cells die.
What is the function of the EGL protein? (1)
Inhibits CED 9, acts as the signal for apoptosis by inhibiting the inhibitor.
What prevents apoptosis and keeps the cell alive?(1)
How does it do this and what protein is involved? (2)
Trophic factors; they release a kinase cascade that leads to phosphorylation of Bad protein.
Why does the phosphorylation of Bad inhibitors apoptosis? (1)
It is unable to bind and inhibit the BCL 2- BCL XI complex at the outer mitochondrial membrane.
Apoptosis inhibitory activity of the complex is not inhibited so apoptosis is inhibited.
