From the following, the correct appearance of a chromosome at the beginning of prophase of mitosis and the number of DNA strands in the chromosome is:

Options

A. Appearance of one chromosome : , Number of DNA strands: 2
B. Appearance of one chromosome : , Number of DNA strands: 4
C. Appearance of one chromosome : , Number of DNA strands: 1
D. Appearance of one chromosome : , Number of DNA strands: 2

Answer

To solve the question regarding the appearance of a chromosome at the beginning of prophase of mitosis and the number of DNA strands in the chromosome, we can follow these steps:

### Step 1: Understand the Structure of a Chromosome
At the beginning of prophase in mitosis, each chromosome consists of two sister chromatids. Each chromatid is a single DNA molecule. Therefore, the chromosome is made up of two DNA strands.

### Step 2: Identify the Chromosome Appearance in Mitosis
During prophase of mitosis, chromosomes condense and become visible under a light microscope. Each chromosome appears as a distinct structure with two sister chromatids joined at a region called the centromere.

### Step 3: Count the DNA Strands
Since each chromosome at the beginning of prophase consists of two sister chromatids, and each chromatid contains one DNA strand, the total number of DNA strands in a single chromosome is two.

### Step 4: Conclusion
Thus, at the beginning of prophase of mitosis, the correct appearance of a chromosome is that it consists of two sister chromatids, and the number of DNA strands in the chromosome is two.

### Final Answer
The correct appearance of a chromosome at the beginning of prophase of mitosis is one chromosome with two DNA strands.

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