Who is academic tutor?

I applied to undergraduate course at UCL after completion of three semesters of BA degree in my home country.
On UCAS I put reference letter from high school teacher who taught me subject which is relevant to my applying courses.

However, just one hour ago I received a request from UCL admissions office as follows:
Please could you arrange for an academic reference from your current degree tutor at where you are taking your BA.
I would be grateful if you could arrange for an academic referee to email me, outlining your suitability for the course and your academic performance to date.

In this case, who is “current degree tutor” who UCL nominated?
Professor, or other person who are working at my university?

It would be the professor that is most in charge of your studies - at uk unis students have a professor who is like the go to for academic support or advice - if you don’t have the equivalent where you live ask one of your professors (either one you know well or one who teaches you a lot) to write it for you

Thank you for your message!
I will ask my professor who offered me interactive discussion class.

However, nominated deadline from UCL is one week after today’s sudden email.
Of course I will do my best to get reference, but one week would not be long enough to arrange it.

If it is difficult to meet the deadline, is to ask admissions office of whether nominated deadline can be postponed or not effective?

Thank you for your message!
I will ask my professor who offered me interactive discussion class.

However, nominated deadline from UCL is one week after today’s sudden email.
Of course I will do my best to get reference, but one week would not be long enough to arrange it.

If it is difficult to meet the deadline, is to ask admissions office of whether nominated deadline can be postponed or not effective?

I would email them and ask I don’t know if they will say yes but if you explain that you are from another country and didn’t realise who your reference had to be and the date you could give it to them they might consider it ?

Just wait a few days. There are thousands of these sort of requests going out and responses coming in. It will take them a bit of time to process them all.

Should I await response more, even if nominated deadline is tomorrow?

They will tell you if they are still waiting - they give a short deadline so that you do something about it.
Stop worrying.