A lot of these fanfictions also deal with the idea of acceptance. Bella has to accept her new state as a vampire, and the Cullen family has to accept her as one of their own. There are often challenges and conflicts related to this acceptance process.
One popular 'Edward bites Bella' fanfiction might be those that explore the emotional aftermath for Bella. For example, it could show how she copes with the new vampire side of her life, like dealing with the thirst for blood and the changes in her relationships with her human friends and family. In some fanfictions, the story may focus on the unique bond between Edward and Bella that is intensified by this significant event.
Another reason could be related to the biology aspect specifically. In the fanfiction, the author may have created a unique lore where there is something in the biology of vampires and humans that makes a bite in a biology class significant. Maybe there are certain chemical reactions that occur only in a scientific environment like a biology class that are essential for the bite to have a particular effect, such as awakening a dormant power within Bella or creating a special bond between them.
One interesting story could be where Edward biting Bella has some unforeseen biological consequences that change the nature of their relationship in unexpected ways. For example, it might give Bella a new ability related to her senses, and the fanfiction could explore how she copes with this new aspect of herself while still being in love with Edward.
One possible scenario could be that Bella is initially terrified but then realizes there's a deeper connection to Edward's bite. Maybe it unlocks some sort of hidden power within her. Another could be that Edward immediately regrets his action and tries to reverse the effects. It could also be that the bite sets off a chain of events in the vampire community, as it's an unexpected and early bite.
One great 'Edward bites Bella fanfiction' is 'The Bite That Changed Everything'. It delves deep into the emotional and physical changes Bella experiences after being bitten. It has a really interesting take on how their relationship evolves post - bite, with some great character development for both Edward and Bella.
You can start by looking on popular fanfiction websites like Archive of Our Own (AO3). There are often a lot of Twilight - related fanfictions there, and you can use the search function to specifically look for ones that involve Edward biting Bella and have a focus on biology. Another option is Fanfiction.net, which also has a large collection of Twilight fanfictions.
It could make other vampires in the story jealous. If Edward biting Bella is seen as a very intimate or special act, other vampires might envy the connection that Edward and Bella are forming. This could lead to some of them trying to interfere in their relationship, either by trying to separate them or by trying to get closer to Bella themselves.
The reaction of the Cullen family is also important. Some fanfictions show them being very protective of Bella, while others might show some members being wary of the new situation. The exploration of Bella's new powers or abilities as a result of the bite is a significant aspect too. For example, she might have a special connection with Jasper's powers or develop her own unique abilities.
One key element is the transformation. When Jacob bites Bella, her physical and mental transformation is often explored in detail. How she adapts to new abilities and instincts is a big part of it.