What is the difference between racism and prejudice?

The difference between racism and prejudice is so subtle that it is difficult to explain. Okay, so racism is the process of making assumptions about a given race. According to seekingliberty.wordpress.com, Racism is the belief that one race is superior to another.  That has to be taught, or developed as a cultural ideology (for example, the Spanish Reconquista, pushing the Moors out of Iberia, used race as a rallying cry). 
Troy Smith writes, Racism, technically (at least according to us wacky academics), is not the same as prejudice. Racism means supporting or being actively invested in the continuation of a racial hierarchy in which ones own group dominates. By this definition, anyone and any member of any group can be prejudiced.  So, racism has to do with race specifically. 
However, this is not necessarily the case. Some people think of racism as discrimination, action, only, rather than holding beliefs of superiority based on race, ethnicity, social status, economic status. 
Eric Zorn in the Chicago Tribune writes that, It's prejudice when Mr. Smith feels unhappy when Mr. Johnson moves in next door because he doesn't like Mr. Johnson's skin color or ethnic identity. Racism is different. It is about taking action in response to someone elses race, based on stereotypes and assumptions. Zorn writes, It's racism when Mr. Smith uses threats and intimidation to attempt to drive Mr. Johnson and his family out of the neighborhood. 
On the other hand, prejudice does not depend on a single race. It is pre judgment of someone based on facts. Seekingliberty.wordpress.com explains, Prejudice is the pre-judging of a situation or person based upon less than all the facts.  Prejudice is a survival mechanism.  It developed to keep us safe: If you see a lion charging at you, you will automatically assume it is going to eat you.  It may actually be coming up to lick your face, but our assumption is that a charging lion wants to eat us.  
Kendra Cherry writes, Prejudice is a baseless and usually negative attitude toward members of a group. Common features of prejudice include negative feelings, stereotyped beliefs, and a tendency to discriminate against members of the group. While specific definitions of prejudice given by social scientists often differ, most agree that it involves prejudgments (usually negative) about members of a group. 
Much like racism, there is a lot more to prejudice. It is not just a negative attitude towards race, however. Cherry adds, Prejudice can be based upon a number of factors including sex, race, age, sexual orientations, nationality, socioeconomic status and religion. 
Finally, Kendra Cherry notes, When prejudice occurs, stereotyping and discrimination may also result. In many cases, prejudices are based upon stereotypes. A stereotype is a simplified assumption about a group based on prior assumptions. Stereotypes can be both positive ("women are warm and nurturing") or negative ("teenagers are lazy"). Stereotypes can lead to faulty beliefs, but they can also result in both prejudice and discrimination 
