Final answer:
The question asks about the digestion of a DNA sequence by EcoRI, which cuts at the sequence GAATTC, resulting in DNA fragments with sticky ends. The number of fragments is determined by the number of EcoRI sites, and their difference refers to the size and sequence of each fragment.
Step-by-step explanation:
The student's question concerns the digestion of a DNA sample by the restriction enzyme EcoRI. When EcoRI recognizes its specific recognition sequence, which is GAATTC, it cuts the DNA at this sequence generating fragments with sticky ends. These sticky ends can then base pair with complementary DNA sequences.
In the given sequence CAGTGAATCTCGAATTCGCTAGTAACGTT, EcoRI would cut the DNA at the GAATTC sites, resulting in two fragments: one before the first GAATTC and one after. The number of fragments produced by this digestion would depend on the number of EcoRI sites present. If there are additional GAATTC sites elsewhere in the DNA not shown in the sample sequence, more fragments would be produced.
The difference between the fragments refers to their size and the sequence of nucleotides they contain. Identification and analysis of these fragments are commonly performed using gel electrophoresis, which separates DNA fragments based on size, with smaller fragments moving faster through the gel. This method helps determine the size and number of the DNA fragments generated after restriction digest.