Question

Write down the complementary strand of \(5'-TAGGCCT-3'\) clearly indicating the \(5'\) and \(3'\) order of complementary strand.

• A. \(3'-ATCCGGA-5'\)
• B. \(5'-ATCCGGA-3'\)
• C. \(3'-UTCCGGA-5'\)
• D. \(5'-UTCCGGA-3'\)

Hint:

DNA base pairing: \[ A \leftrightarrow T \] \[ G \leftrightarrow C \] DNA strands are antiparallel.

Answer 1

The Correct Option is A

Concept: DNA strands are:
• Complementary
• Antiparallel Base pairing rules: \[ A \leftrightarrow T \] \[ G \leftrightarrow C \]

Step 1: Write the original DNA strand. Given strand: \[ 5'-TAGGCCT-3' \]

Step 2: Apply complementary base pairing. Corresponding complementary bases: \[ T \rightarrow A \] \[ A \rightarrow T \] \[ G \rightarrow C \] \[ G \rightarrow C \] \[ C \rightarrow G \] \[ C \rightarrow G \] \[ T \rightarrow A \] Thus complementary sequence becomes: \[ ATCCGGA \]

Step 3: Understand antiparallel orientation. DNA strands run in opposite directions. Therefore if original strand is: \[ 5' \rightarrow 3' \] then complementary strand must be: \[ 3' \rightarrow 5' \] Hence: \[ \boxed{ 3'-ATCCGGA-5' } \]

Step 4: Analyze options carefully.
• Options containing U are incorrect because U is present in RNA not DNA.
• Complementary strand must be antiparallel. Thus correct answer is: \[ \boxed{ 3'-ATCCGGA-5' } \]

Step 5: Choose correct answer. Hence correct option is: \[ \boxed{(1)} \] Final Conclusion: Complementary strand of: \[ 5'-TAGGCCT-3' \] is: \[ \boxed{ 3'-ATCCGGA-5' } \] Hence correct answer is: \[ \boxed{(1)} \]