"Denying someone a promotion because he/she is supporting a political candidate you do not want" is showing bias.

"Firing a woman from her job upon learning her pregnancy" is showing prejudice.

"Offering a higher pay to a newly hired Christian employee over a Muslim employee for 10 years" is an example of prejudice.

"Putting up more restrooms for women than for men" is an example of bias.

"Moving a black student  over a white student at the back of the room" is an example of bias.