The cell that dismantles itself

Science · Organisms & Life Processes · ages 20-21

Name ______________________ Date ____________

Why does a cell keep its death machinery ready but inactive?
- To save energy during the cell cycle
- To divide faster when growth factors arrive
- To activate the kill in seconds when ordered
What happens to the contents of a cell undergoing apoptosis?
- It spills its contents and inflames the tissue
- It packs itself into neat parcels that neighbors swallow
- It swells until it bursts randomly
A broken death pathway can grow a tumor without any extra division speed. True or false?
Circle one: True False
What role do mitochondria play in apoptosis?
- It copies the DNA one last time
- It pumps in extra nutrients
- It releases cytochrome c to build the apoptosome
How does a caspase cascade work?
- Initiators sense the order and switch on executioners, multiplying the signal
- One caspase cuts one target and then stops
- Executioners block the initiators to slow death
How does the cell cycle connect to the death decision?
- They speed the cycle past every checkpoint
- They halt the cycle for repairs, ordering death only when damage is beyond fixing
- They delete the death machinery to protect division
A tissue overgrows while its cells divide at the normal rate. What explains the extra cells?
- Extra division speed
- Stronger growth signals
- Missing deaths of cells that should have died
How do cancer cells exploit the death pathway?
- Dodge apoptosis and pile up, fed by vessels they order built
- Divide twice as fast as healthy cells
- Repair all DNA damage perfectly

Answer key

For grown-ups. Fold this page away before handing over the rest.

To activate the kill in seconds when ordered · Stocked sleeping procaspases switch on fast, since building them on demand would be too slow.
It packs itself into neat parcels that neighbors swallow · Ordered dismantling keeps the contents wrapped, so neighbors stay unharmed.
True · A broken death pathway grows a tumor by letting cells live that should have died.
It releases cytochrome c to build the apoptosome · The organelle acts as the point of no return by launching the first caspase.
Initiators sense the order and switch on executioners, multiplying the signal · Each cascade level multiplies the kill signal across hundreds of structural targets.
They halt the cycle for repairs, ordering death only when damage is beyond fixing · Division control and death control share the same inspectors by design.
Missing deaths of cells that should have died · Growth from missing deaths looks like overgrowth, but the division rate never changed.
Dodge apoptosis and pile up, fed by vessels they order built · Escaping programmed death removes one constraint on growth, letting survivors accumulate.