The members of a homologous pair of chromosomes

Options

A. are identical in size and appearance
B. contain identical genetic information
C. seperation and move to opposite poles of the cell during mitosis
D. are found only in hploid cells.

Explanation

### Step-by-Step Solution:

1. **Understanding Homologous Chromosomes**:
- Homologous chromosomes are pairs of chromosomes in a diploid organism that have the same structural features, such as size, shape, and banding pattern. They are similar but not identical in terms of genetic information.

2. **Characteristics of Homologous Chromosomes**:
- **Size and Appearance**: Members of a homologous pair are identical in size and appearance. This means they have the same length and shape.
- **Gene Location**: The genes on homologous chromosomes are located at the same positions (loci). However, the alleles (variations of a gene) at these loci may differ between the two chromosomes.

3. **Genetic Information**:
- While homologous chromosomes have the same genes, they do not contain identical genetic information. For example, one chromosome may carry an allele for blue eyes, while the homologous chromosome may carry an allele for brown eyes.

4. **Presence in Cells**:
- Homologous chromosomes are found in diploid cells (2n), meaning they contain two sets of chromosomes, one from each parent. They are not found in haploid cells (n), which contain only one set of chromosomes.

5. **Behavior During Cell Division**:
- During meiosis, homologous chromosomes pair up and can exchange genetic material through a process called crossing over. They separate into different gametes, ensuring genetic diversity. In mitosis, sister chromatids (not homologous chromosomes) separate.

6. **Evaluating the Options**:
- **Option A**: Members of homologous pairs are identical in size and appearance. (Correct)
- **Option B**: They contain identical genetic information. (Incorrect)
- **Option C**: They separate and move to opposite poles of the cell during mitosis. (Incorrect; this occurs during meiosis for homologous chromosomes)
- **Option D**: They are found only in haploid cells. (Incorrect; they are found in diploid cells)

7. **Conclusion**:
- The correct option is **Option A**: Members of a homologous pair of chromosomes are identical in size and appearance.