In DNA one strand direction of 5'-3' the other stand is

Options

A. 5'-3'
B. 5'-5'
C. 3'-3'
D. 3'-5'

Answer

To determine the direction of the second strand of DNA when one strand is oriented from 5' to 3', we can follow these steps:

### Step-by-Step Solution:

1. **Understanding DNA Structure**: DNA is composed of two strands that run in opposite directions, known as antiparallel strands. Each strand has a directionality defined by the orientation of its sugar-phosphate backbone.

2. **Identifying the 5' and 3' Ends**: The ends of a DNA strand are labeled based on the carbon atoms of the sugar molecule. The 5' end has a phosphate group attached to the 5th carbon of the sugar, while the 3' end has a hydroxyl group (-OH) attached to the 3rd carbon.

3. **Direction of the First Strand**: If one strand of DNA is oriented from 5' to 3', it means that the strand starts with a phosphate group at the 5' end and ends with a hydroxyl group at the 3' end.

4. **Determining the Direction of the Second Strand**: The second strand of DNA must run in the opposite direction to maintain the antiparallel structure. Therefore, if the first strand is 5' to 3', the second strand will be oriented from 3' to 5'.

5. **Conclusion**: Thus, if one strand of DNA is in the 5' to 3' direction, the complementary strand will be in the 3' to 5' direction.

### Final Answer:
The direction of the other strand is 3' to 5'.

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