I wonder if we could use the followings interchangeably, if not, what's the differences between them?
1. When we use a noun or a pronoun as an object of "decide" or "decide on",for example:
I have got to decide our whole future.
I have had to decide on every step.

2. The followings are from dictionaries or other books:
open the door， open up the front door
open up the cupboard\the package\ the stomach

It's necessary to open another bookshop here.
We've decided to open up a new restaurant with modern equipment.
open up a new supermarket


Thanks a lot