Yes questions from 11 std are also asked in the GUJCET. and let me also guide you that if you think I can study 12th and score good marks without 11th then trust me it's not possible. I used to be the same guy who used to think that I'll crack MHCET with 12th studies and would ignore 11th. But trust me everything is in a flow. Without basics taught in 11, we cannot completely clear the concepts of 12th. So my personal request to you study chapters from both the standards really well.

To know the GUJCET syllabus in detail, refer to the following site..

https://engineering.careers360.com/articles/gujcet-syllabus

Best wishes. Thank-you.