I'm reading the Cade book and have just started Chapter 4 Design Patterns.It says in the Prerequisite Review
This chapter assumes that you're already familiar with the Gang of Four(GoF)patterns, as described in "Design Patterns: Elements of Reusable Object-Oriented Software".This chapter reviews the patterns in the context of the exam objectives to cover the material necessary for the exam
Does this mean one has to read the GoF book in order to be ready for part1 of the exam or a basic knowledge of patterns is sufficient?
The Cade book goes on to tell you (in brief) what you need to know for the exam about each of the patterens, so if you have a general understanding of most of the patterns then I think you should be ok working with the Cade book and searching the web, or asking here, where you have questions or are unsure.