A chromosome with centromeres and arms in 1:1 ratio is

Options

A. Metacentric
B. Sub metacentric
C. Acrocentric
D. Telocentric

Answer

To determine the type of chromosome that has centromeres and arms in a 1:1 ratio, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Chromosome Structure**:
- A chromosome consists of two arms and a centromere. The position of the centromere divides the chromosome into two sections.

2. **Identify Chromosome Types**:
- Chromosomes can be classified based on the position of the centromere:
- **Metacentric**: The centromere is located in the middle, resulting in two equal arms. This gives a 1:1 ratio of the arms.
- **Sub-metacentric**: The centromere is slightly off-center, leading to one arm being longer than the other. This results in an unequal ratio.
- **Acrocentric**: The centromere is located closer to one end, resulting in one very short arm and one long arm.
- **Telocentric**: The centromere is at the very end of the chromosome, resulting in only one arm.

3. **Analyze the Given Ratio**:
- The question specifies a 1:1 ratio of the arms. This indicates that the two arms must be equal in length.

4. **Determine the Correct Answer**:
- Since the only chromosome type that has equal arms (1:1 ratio) is the **metacentric chromosome**, we conclude that the correct answer is option A: **Metacentric**.

### Final Answer:
The chromosome with centromeres and arms in a 1:1 ratio is **metacentric** (Option A).