Final answer:
Dideoxynucleotides (ddNTPs) differ from deoxynucleotides (dNTPs) in terms of structure and function. ddNTPs lack the 3' hydroxyl group, which prevents further nucleotide addition in DNA synthesis. This structural difference makes ddNTPs useful in the dideoxy chain termination method of DNA sequencing.
Step-by-step explanation:
Dideoxynucleotides (ddNTPs) differ from typical deoxynucleotides (dNTPs) in their structure and function. The dideoxynucleotide is similar in structure to a deoxynucleotide, but it lacks the 3' hydroxyl group, which is important for the addition of more nucleotides during DNA synthesis. When a ddNTP is incorporated into a DNA strand, DNA synthesis stops because the free 3' OH group needed to add another nucleotide is not available.
The lack of the 3' hydroxyl group in ddNTPs makes them useful in the dideoxy chain termination method of DNA sequencing. By using a predetermined ratio of deoxynucleotides to dideoxynucleotides, it is possible to generate DNA fragments of different sizes. Each ddNTP, when incorporated into the DNA strand during sequencing, terminates the chain at a specific nucleotide position, allowing the determination of the DNA sequence.
In summary, ddNTPs differ from dNTPs in their structure by lacking the 3' hydroxyl group. This structural difference affects their function by preventing further nucleotide addition in DNA synthesis and enabling them to be used in the dideoxy chain termination method of DNA sequencing.