Google(s GOOG) already has some really compelling apps that are meant to replace core services on the iPhone: apps like Gmail, Drive, Google Maps, Chrome, Capture and others. Now with an update to the Google Search app for iOS(s AAPL), the company has effectively trained its sights on Siri by adding Google Now to iOS.

Google Now has been an integrated feature of Android 4.1 since June 2012, but starting Monday, it will, for the first time, be available on the iOS platform. (And no, Google did not have any problem getting the app approved, company representatives said.) The service, which draws on a wealth of user information in Google’s mobile apps and desktop services, aims to give users relevant answers to questions before they’ve even asked them. That information pops up on a “card” on the screen.

For example: if you’ve entered your work address, every morning when…