A denatured protein or DNA molecule has lost its :

Options

A. hydrogen bonds
B. function
C. shape
D. all of these

Explanation

To answer the question "A denatured protein or DNA molecule has lost its:", we will analyze the components and implications of denaturation in both proteins and DNA.

### Step-by-Step Solution:

1. **Understanding Denaturation**:
- Denaturation refers to the process where proteins or nucleic acids lose their native structure due to the disruption of various bonds and interactions that maintain their shape.

2. **Proteins**:
- Proteins are composed of amino acids linked together by peptide bonds. They also have secondary, tertiary, and quaternary structures maintained by various interactions, including hydrogen bonds.
- When a protein is denatured, these hydrogen bonds can break, leading to a loss of the protein's specific three-dimensional structure.

3. **DNA**:
- DNA is made up of nucleotides, which are connected by phosphodiester bonds. The two strands of DNA are held together by hydrogen bonds between complementary bases.
- Denaturation of DNA involves the breaking of these hydrogen bonds, resulting in the separation of the two strands.

4. **Consequences of Denaturation**:
- Loss of Hydrogen Bonds: The primary effect of denaturation is the loss of hydrogen bonds, which are crucial for maintaining the structure of both proteins and DNA.
- Loss of Function: The specific shape of a protein is essential for its function. When denatured, the protein cannot perform its biological role effectively.
- Loss of Shape: The overall conformation of the protein or DNA is altered, leading to a change in its physical properties.

5. **Conclusion**:
- Therefore, a denatured protein or DNA molecule has lost its hydrogen bonds, function, and shape. The correct answer is "all of these."

### Final Answer:
A denatured protein or DNA molecule has lost its: **All of these** (hydrogen bonds, function, and shape).

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