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Question

The following represents a small section of one strand of DNA:

5’ TACATGTGGCCACT 3’

How should the complementary strand of DNA be represented?
A. ATGTACACCGGTGA 5’
B. ’ AUGUAGAGGCCUGA 5’
C, ’ UTGTUCUCCGGTGU 3’
D. ’ TACATGTGGCCACT 3’

Answer 1

To determine the complementary strand of DNA for the given sequence \( 5' , TACATGTGGCCACT , 3' \), we need to match each base with its complementary base:

• A (Adenine) pairs with T (Thymine)
• T (Thymine) pairs with A (Adenine)
• G (Guanine) pairs with C (Cytosine)
• C (Cytosine) pairs with G (Guanine)

Now, let's write the complementary strand from 3' to 5':

1. T pairs with A
2. A pairs with T
3. C pairs with G
4. A pairs with T
5. T pairs with A
6. G pairs with C
7. T pairs with A
8. G pairs with C
9. G pairs with C
10. C pairs with G
11. A pairs with T
12. C pairs with G
13. T pairs with A

So, when we write the complementary strand from 3' to 5', we get:

\( 3' , ATGTACACCGGTGA , 5' \)

It's common to write complementary strands in the conventional orientation of 5' to 3', so we can reverse this:

Thus, the complementary DNA strand can be represented as:

\( 5' , ATGTACACCGGTGA , 3' \)

So the correct answer among the options is:

A. 5' ATGTACACCGGTGA 3'