Final answer:
The first nucleotide in the DNA fragment ATGC is A (adenine), which is found at the 5' end of the fragment.
Step-by-step explanation:
The first nucleotide in the DNA fragment ATGC is A (adenine). This fragment is read from the 5' to 3' direction, and by convention, sequences are written in this orientation. Therefore, the first nucleotide is 'A' which stands at the 5' end of the DNA fragment.