Chromosomes in a bacterial cell can be 1 in number and

Options

A. Are always circular with more `G -= C` content
B. Are always linear with more `G -= C` content
C. Can be either circular or linear, but never both within the same cell
D. Can be circular as well as linear within the same cell

Answer

**Step-by-Step Solution:**

1. **Understanding Bacterial Chromosomes:**
- Bacteria typically have one to three chromosomes. They can exist as a single chromosome or multiple chromosomes.

2. **Structure of Bacterial DNA:**
- The DNA in bacterial cells is usually circular and single-stranded. This circular DNA is a characteristic feature of most bacteria.

3. **Examples of Bacterial Chromosomes:**
- The first observation of circular DNA in bacteria was in *Rhodobacter spheroides*, a gram-negative bacterium.
- In contrast, *Bacillus burgdorferi* has been observed to have two linear chromosomes, which is an exception to the typical circular structure.
- Another example is *Agrobacterium tumefaciens*, which has one circular and one linear chromosome.

4. **Analyzing the Options:**
- The question provides several options regarding the nature of bacterial chromosomes:
- Always circular with more guanine-cytosine (GC) content.
- Always linear with more GC content.
- Can be either linear or circular but never within the same cell.
- Can be circular as well as linear.

5. **Conclusion:**
- Based on the examples and characteristics discussed, bacteria can have chromosomes that are either circular or linear, and in some cases, both types can exist within the same cell. Therefore, the correct option is: "can be circular as well as linear."