Morkel has now taken Cook's wicket 10 times in Tests, more than any bowler.
Johannesburg born and raised Jennings, the 11th man tried as an England Test opener alongside Alastair Cook since Andrew Strauss retired in 2012, was under pressure for his place after a run of low scores - including a duck in the first innings of this match.
Vernon Philander has been passed fit to bat for South Africa as they try to avoid a follow-on in the third Test against England at The Oval today.
Bavuma had just one minor scare on 40, when Ben Stokes nearly pulled off the most brilliant of catches at gully, flinging himself to his left to intercept a skewed drive off Stuart Broad - with the total on 148.
But South Africa moved past the follow-on mark of 153 without him, during Bavuma (52) and Morne Morkel's ninth-wicket stand of 47 in this third Investec Test.
Stokes could not quite cling on, and in Broad's next over South Africa were safely within 200 runs of England's total after a Bavuma cover-drive for four.
Bavuma reached fifty with a streaky boundary through the slips cordon, having earlier enjoyed a life when Ben Stokes dropped a tough chance in the gully, but the South African was eventually Roland-Jones' fifth victim, edging through to Jonny Bairstow behind the stumps.
Bavuma's defiant knock was then brought to an end by Roland-Jones, who induced a nick behind to finish with 5-57 and a place on the honours board at The Oval.
Left-hander Jennings was on 33 when given out lbw to fast bowler Kagiso Rabada but his review of umpire Joel Wilson's decision showed the ball had pitched just outside his leg stump.