The nucleotides represented in the DNA `5^1`____ CA CA CA CA CA _______ `3^(1)` are called

Options

A. Repetitive sequences
B. cDNA
C. r DNA
D. Retro DNA

Answer

To solve the question regarding the nucleotides in the DNA sequence `5' ____ CA CA CA CA CA ______ 3'`, we need to analyze the sequence and determine what type of sequence it represents. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Sequence
The sequence provided is `5' ____ CA CA CA CA CA ______ 3'`. The key part of this sequence is the repetition of "CA".

### Step 2: Understand the Concept of Repetitive Sequences
Repetitive sequences in DNA are characterized by the presence of the same nucleotide sequence repeated multiple times. In this case, "CA" is repeated several times.

### Step 3: Evaluate the Options
Now, let’s consider the options given:
1. **Repetitive Sequence**: This option refers to sequences where the same base pairs are repeated.
2. **cDNA (Complementary DNA)**: This is synthesized from mRNA and does not pertain to repetitive sequences.
3. **rDNA (Recombinant DNA)**: This refers to DNA that has been artificially made by combining DNA from different organisms.
4. **Retro DNA**: This term is associated with DNA from retroviruses and is not relevant here.

### Step 4: Match the Sequence with the Correct Option
Given that the sequence "CA" is repeated multiple times, it fits the definition of a repetitive sequence.

### Conclusion
The correct answer is **Option A: Repetitive Sequence**.

---