Mutation of DNA occurs due to changes in the sequence of one of the following

Options

A. Bases
B. Ribose units
C. Phosphate units
D. Sugar units

Explanation

To answer the question regarding the mutation of DNA and the changes in the sequence, we can break down the solution step by step.

### Step-by-Step Solution:

1. **Understanding DNA Structure**:
- DNA is composed of nucleotides, each of which contains a sugar, a phosphate group, and a nitrogenous base. The sequence of these nitrogenous bases (adenine, thymine, cytosine, and guanine) encodes genetic information.

**Hint**: Recall the components of a DNA nucleotide and their arrangement in the double helix.

2. **Definition of Mutation**:
- A mutation refers to any change in the nucleotide sequence of DNA. This can occur due to various factors, including errors during DNA replication, exposure to radiation, or chemical mutagens.

**Hint**: Think about what constitutes a mutation and how it can affect genetic information.

3. **Types of Mutations**:
- Mutations can be classified into several types, such as point mutations (changes in a single nucleotide), insertions, deletions, and larger chromosomal mutations. Point mutations can further be categorized into silent, missense, and nonsense mutations based on their effects on protein synthesis.

**Hint**: Consider the different ways in which the sequence of bases can be altered.

4. **Impact of Mutations**:
- Changes in the sequence of nitrogenous bases can lead to changes in the expression of genes, potentially resulting in altered traits or diseases. For example, a single nucleotide change can lead to a different amino acid being incorporated into a protein, which may affect its function.

**Hint**: Reflect on how mutations can influence phenotype and gene expression.

5. **Conclusion**:
- Therefore, the mutation of DNA occurs due to changes in the sequence of nitrogenous bases. This alteration can have significant implications for the organism, affecting everything from physical traits to susceptibility to diseases.

**Hint**: Summarize the core idea that mutations arise from changes in the sequence of bases in DNA.

### Final Answer:
Mutation of DNA occurs due to changes in the sequence of nitrogenous bases.