What is the complementary DNA strand for the sequence ATC GCA TGG ATCG?

What is the complementary DNA strand for the sequence ATC GCA TGG ATCG?

• A. TAG CGT ACC TAGC
• B. ATC GCA TGG ATCG
• C. TCG ATT CGA CGA
• D. TAG CGA ACC TCG

Answer: (A)

Base pairing rules determine complementary strands: A pairs with T and C pairs with G. To build the complementary strand, replace each base in the given sequence with its partner in the same order: A→T, T→A, C→G, G→C. Doing this for ATCG CGA TGG ATCG yields TAGCGTACCTAGC. That sequence matches the option starting with TAGCGTACCTAGC, which is why it’s the correct complement. The other sequences don’t fit because they either repeat the original sequence, have incorrect length, or mix bases in a way that doesn’t follow the A↔T and C↔G pairing.

Base pairing rules determine complementary strands: A pairs with T and C pairs with G. To build the complementary strand, replace each base in the given sequence with its partner in the same order: A→T, T→A, C→G, G→C. Doing this for ATCG CGA TGG ATCG yields TAGCGTACCTAGC. That sequence matches the option starting with TAGCGTACCTAGC, which is why it’s the correct complement. The other sequences don’t fit because they either repeat the original sequence, have incorrect length, or mix bases in a way that doesn’t follow the A↔T and C↔G pairing.