It is a fishing reference. The question is like a "baited hook" and you indicate with the use of that phrase you are willing to "take the bait" or "bite the hook" knowing the other person is "fishing" for an interaction of some kind. Saying "I am in" eludes to being "counted in" like is a hand of a card game. It is possible for you to want to "enter a card game hand" as the pot would be the bait. There is a subtle difference though.

I'll take a bite at your question. It means "tell me more," or "I'll try to solve this problem" depending on the context. It isn't a phrase that I hear a lot in the USA, but everyone knows what it means.