5505 asa running config and resets

I have a basic question in regards to a cisco asa 5505.

I'm not sure I understand the configuration lifetime.

Is a write mem required after a config change in order for the device to retain the current running config in case of say a power outage?

is a reload command essentially the same as a power cycle event?

If reload loads config from flash, is there a command to simply reset? (No mem write and retain current running config?)

Thanks!