The dog ate my homework Helper, the family dog, eating his homework. "I didn't know dogs actually did that", he says, and finds his teacher equally incredulous since he had used that excuse before. In a later episode, when the dog goes to work for the police, Bart must eat his own homework for the excuse to work. When Mrs. Krabappel begins dating Ned Flanders, the Simpsons' neighbor, at the end of the 2011 season, she sees Santa's Little Helper in the Simpsons' yard and asks if he is the dog who has eaten Bart's homework so many times. Bart's attempts to demonstrate this and
Helper dependent virus and capsid encoding DNA, plus helper DNA. Every cell that is successfully transfected with all three DNA fragments will produce the necessary proteins to produce infective viruses. These viruses will only have transgenic DNA encapsidated and therefore once they've infected a patient's cell, they will not be capable of reproducing. Helper dependent viruses can also occur in nature without being "gutted". The term satellite virus has been given to a large group of viruses that all require the presence of another virus to replicate. Many of these are plant viruses, but animal viruses can be seen in the case of