If a portion of strand of DNA bases reads 5’ AGCTAGCGT 3’, what would the sequence of bases on the complementary strand read?
A.
5’ UCGAUCGCA 3’
B.
3’ TCGATCGCA 5’
C.
5’ TCGUTCGCU 3’
D.
3’ AGCTAGCGT 5’
To determine the sequence of the complementary DNA strand, you need to follow the base-pairing rules of DNA:
- Adenine (A) pairs with Thymine (T)
- Cytosine (C) pairs with Guanine (G)
Given the original DNA strand reads: 5’ AGCTAGCGT 3’
The complementary strand is read in the 3′ to 5′ direction and matches as follows:
- A (adenine) pairs with T (thymine)
- G (guanine) pairs with C (cytosine)
- C (cytosine) pairs with G (guanine)
- T (thymine) pairs with A (adenine)
Therefore, the complementary strand will read: 3’ TCGA TC GCA 5’
Reversing the direction to match the standard 5′ to 3′ orientation for the complementary strand:
5’ TCGATCGCA 3’
So the correct answer is:
B. 3’ TCGATCGCA 5’