I'm not sure using the word "Patrician" in this case (when talking about the late republic) is accurate. By that point almost all legal privileges patrician had were abolished and plebeians aspiring for a public career generally actually had more opportunities (you had to be one to stand for election as a people's tribune and at least one consul legally had to be a plebian).
By that point Rome was a full on plutocracy and most senators/nobles weren't patricians. Probably one the most famous Roman "lawyer" Cicero was not only a plebian but a complete no-name from a provincial town (and most famous Romans from his time like Cato, Pompey, Brutus, Mark Anthony, Octavian were all plebian while Ceasar, Lepidus and Metellus Scipio were patrician) .
It was possible to switch from patrician to plebeian and vice versa by adoption. Clodius is the best known example of the former and Octavian of the latter.
By that point Rome was a full on plutocracy and most senators/nobles weren't patricians. Probably one the most famous Roman "lawyer" Cicero was not only a plebian but a complete no-name from a provincial town (and most famous Romans from his time like Cato, Pompey, Brutus, Mark Anthony, Octavian were all plebian while Ceasar, Lepidus and Metellus Scipio were patrician) .