Ends of chromosomes exhibiting polarity and offering stability are known as

Options

A. Knobs
B. Chromomeres
C. Satellites
D. Telomeres

Answer

### Step-by-Step Solution:

1. **Understanding Chromosome Structure**:
- Chromosomes are structures within cells that contain DNA. Each chromosome has two ends, which are crucial for its stability and integrity.

2. **Identifying the Ends of Chromosomes**:
- The ends of chromosomes are known to exhibit polarity, meaning they have distinct structural characteristics at each end.

3. **Defining Telomeres**:
- The specific term for the ends of chromosomes that provide stability and exhibit polarity is "telomeres."

4. **Composition of Telomeres**:
- Telomeres are composed of repetitive sequences of non-coding DNA. In humans, the specific sequence found in telomeres is TTAGGG.

5. **Function of Telomeres**:
- Telomeres serve several important functions:
- They protect chromosomes from deterioration.
- They prevent chromosomes from fusing with each other.
- They play a role in cellular aging, as telomeres shorten with each cell division.

6. **Telomere Shortening and Aging**:
- Each time a cell divides, the telomeres become shorter. This shortening is linked to the aging process in humans. When telomeres become critically short, it can lead to cell senescence or death, contributing to the aging process.

7. **Role of Telomerase**:
- Telomerase is an enzyme that can extend the length of telomeres. It is active in certain cells, such as stem cells and cancer cells, allowing them to divide indefinitely without aging.

8. **Conclusion**:
- Therefore, the ends of chromosomes that exhibit polarity and offer stability are known as telomeres.

### Final Answer:
The ends of chromosomes exhibiting polarity and offering stability are known as **telomeres**.

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