Answer:
Step-by-step explanation:
For a double-stranded DNA composed of 10 base pairs, we can choose any of the four nucleotides (A, G, C, or T) for the first base on one strand. Then, since A pairs with T and G pairs with C, there is only one possible nucleotide for the second base on the same strand. For the third base, we again have four choices, but the fourth base must be the complementary base on the other strand, so there is only one possible choice. We continue in this way for all 10 bases, resulting in a total of:
4 (choices for first base) x 1 (complementary base on second strand) x 4 (choices for third base) x 1 (complementary base on fourth strand) x 4 (choices for fifth base) x 1 (complementary base on sixth strand) x 4 (choices for seventh base) x 1 (complementary base on eighth strand) x 4 (choices for ninth base) x 1 (complementary base on tenth strand)
= 4^5
= 1024
Therefore, there are 1024 different double-stranded DNA molecules composed of 10 base pairs that could possibly exist.
If DNA were single-stranded instead of double-stranded, then we could choose any of the four nucleotides (A, G, C, or T) for each of the 10 positions independently of each other. Therefore, the total number of possible single-stranded DNA molecules composed of 10 base pairs would be:
4 (choices for first base) x 4 (choices for second base) x 4 (choices for third base) x 4 (choices for fourth base) x 4 (choices for fifth base) x 4 (choices for sixth base) x 4 (choices for seventh base) x 4 (choices for eighth base) x 4 (choices for ninth base) x 4 (choices for tenth base)
= 4^10
= 1048576
Therefore, there are 1048576 different single-stranded DNA molecules composed of 10 base pairs that could possibly exist.