Do we always say 'take up' instead of 'take' talking about job?
He learned that John Verghese had taken up a job as a trainee at a well known bank in the City.

Question

Answer

Actually we use 'take' a job more often and we use' take up' when we talk about starting a new hobby, sport or other pastime.

Answer

"To take up" means to begin doing some activity. I agree with Jacqui, it's more to to with pastimes, not work.

Answer

take a job = start a job
take up a job = accept the offer and start the job

Answer

He learned that John Verghese had accepted a job as a trainee at a well known bank in the City.