Seriously take a chill pill. On my trail everyone had a portfolio the dudes carried them too, if only to be able to carry the packets of paper they always give you.
Mine had copies of my application, PS, CV, research publications, list of questions to ask, notes I had taken as research about the program, the lastest AMA bulletin or something so I could talk about Obamacare or whatever current events in medicine, etc
There is often plenty of downtime in those rooms where it's just you and other applicants, that stuff can keep you busy and looking sharp
During the ubquitous ppt it's fine to take notes especially if they pass out slides.
I would even jot things down during AM report. It's fine in these instances you're not talking with people just paying attention. I would glance up and be making eye contact so you don't seem in your own little universe but attentive.
Having my list saved me for the interviews where they would glance at their watch after 4 min of BS chat how are you, and say "we have 20 minutes left. Any questions?"
It allowed me to be the creator of the conversation and keep it afloat. Don't deny yourself that crutch, it's not weird if you do it right. Like has been said, just don't make them sit there watching you write an essay for 50 seconds after each question they answer. Don't make it an interrogation. Don't robotically work off that list. Don't make them sit there where you look through those questions, have some off the top of your head and use the list when it becomes clear that it's time for hardcore Q & A to have an interview with this silent Joe at all.
Don't go the other way and forgo a useful tool. You want to appear prepared, engaged, organized, etc. I think it is an invaluable tool to YOURSELF personally to be able to write notes, and I also think it helps your image to OTHERS. But do people sabotage themselves with it as warned above? Of course they can.
TLDR:
bring your darn portfolio
don't bury your nose in it or make people watch you write
this isn't the Spanish inquisition
keep it brief, organized, flowing
be prepared to float the convo with a game of 20 questions
know when to quit