What does "embedded jock stereotype" mean in the text below?
I was watching The Vampire Diaries when I encountered the phrase above. There is a scene that a history teachers asks his students about the casualties of a historic battles. The calls the students once at a time. They don't know the answers. Here is the transcript;
Teacher: The battle of Willow Creek took place right at the end of the war in our very own Mystic Falls.How many casualties resulted in this battle?.... Ms. Bennett?
B: Um... a lot? I'm not sure.Like a whole lot.
T: Cute becomes dumb in an instant, Ms. Bennett.
Mr. Donovan.Would you like to take this opportunity to overcome your embedded jock stereotype?
D: It's okay, Mr. Tanner, I'm cool with it.
T: Hmm. Elena? Surely you can enlighten us about one of the town's most significantly historical events?
E: I'm sorry, I-- I don't know.
T: I was willing to be lenient last year for obvious reasons, Elena, but the personal excuses ended with summer break.

The student who is called Mr. Donovan is very good at football and always wears sport clothes with football teams emblems.

Question

What does "embedded jock stereotype" mean in the text below? 
I was watching The Vampire Diaries when I encountered the phrase above. There is a scene that a history teachers asks his students about the casualties of a historic battles. The calls the students once at a time. They don't know the answers. Here is the transcript;
Teacher: The battle of Willow Creek took place right at the end of the war in our very own Mystic Falls.How many casualties resulted in this battle?.... Ms. Bennett?
B: Um... a lot? I'm not sure.Like a whole lot.
T: Cute becomes dumb in an instant, Ms. Bennett.
Mr. Donovan.Would you like to take this opportunity to overcome your embedded jock stereotype?
D: It's okay, Mr. Tanner, I'm cool with it.
T: Hmm. Elena? Surely you can enlighten us about one of the town's most significantly historical events?
E: I'm sorry, I-- I don't know.
T: I was willing to be lenient last year for obvious reasons, Elena, but the personal excuses ended with summer break.

The student who is called Mr. Donovan is very good at football and always wears sport clothes with football teams emblems.

Answer

A stereotype is a group of characteristics that are used to collectively describe a certain group of people. It is often a negative concept however, as those characteristics can be wrongly ascribed to others in the group.
Embedded is something that is deeply ingrained, and/or fundamental.
As a non-American, I have to go with what I've picked up from TV for 'Jock', which is mainly used in North America. It is used to describe someone whose primary focus is on sports, rather than academic achievement. I believe that it was derived from 'Jock Strap' - another name for an athletic supporter. 
So - the phrase refers to someone whose  total focus is on sports, who fundamentally defines themselves as a sporting person, and surrounds themselves with sporting icons.