1. Key unit of contraction composed of bundled parallel protein myofilaments 2. This part of muscle cell transmits AP.

i am not sure but i think you talk about myosin it is bind with ATP to do the contraction with actin

No

Explanation:

Viruses can not be cured, but vaccines prevent them from spreading. Viruses arent living things, but they need a host (human, animal, or plant) to reproduce. When i virus enters the body, your body's cells fight the virus (thats why you get a fever). Vaccinations for viruses are made up of dead parts of the virus so that your body can "train" itself to fight that virus. So, no, there is no cure for viruses but you can prevent them. People are working on antiviral drugs (anti= against viral=virus) to combat them, but so far, these only weaken some viruses, none can completely cure it.