Given a scientific passage and an answer, generate a question for the given answer.

Passage: Unsaturated hydrocarbons that contain at least one double bond are called alkenes . The name of a specific alkene always ends in ene , with a prefix indicating the number of carbon atoms. Figure below shows the structural formula for the smallest alkene. It has just two carbon atoms and is named ethene. Ethene is produced by most fruits and vegetables. It speeds up ripening and also rotting. Figure below shows the effects of ethene on bananas. Answer: alkenes
What is the name for unsaturated hydrocarbons that contain at least one double bond?