Which of the following statements is not true about RNA?

Options

A. It controls the synthesis of protein
B. It is present in the nucleus of the cell
C. It has always double stranded `laphhelix structure
D. None of these

Explanation

To determine which statement is not true about RNA, let's analyze the characteristics of RNA step by step.

### Step 1: Understand what RNA is
RNA stands for ribonucleic acid. It is a crucial molecule in the biology of cells, primarily involved in the synthesis of proteins.

**Hint:** Remember that RNA is different from DNA in structure and function.

### Step 2: Identify the types of RNA
There are three main types of RNA:
1. **Messenger RNA (mRNA)** - carries the genetic information from DNA to the ribosome.
2. **Ribosomal RNA (rRNA)** - makes up the ribosomes, where proteins are synthesized.
3. **Transfer RNA (tRNA)** - transfers amino acids to the ribosome during protein synthesis.

**Hint:** Each type of RNA has a specific role in protein synthesis.

### Step 3: Location of RNA in the cell
RNA is primarily found in the cytoplasm of the cell, where it plays a key role in protein biosynthesis. However, it is also synthesized in the nucleus.

**Hint:** Consider where RNA is produced versus where it functions.

### Step 4: Structure of RNA
RNA is typically single-stranded and can form various structures, including alpha helices. It does not have a double-stranded helical structure like DNA.

**Hint:** Focus on the structural differences between RNA and DNA.

### Step 5: Replication of RNA
Unlike DNA, RNA does not replicate itself. Instead, it is synthesized from DNA when needed.

**Hint:** Think about the processes of transcription and replication.

### Step 6: Evaluate the statements
Now, let's evaluate the statements provided in the question:
1. RNA controls the synthesis of proteins - **True**
2. RNA is present in the nucleus of the cell - **True**
3. RNA has always a double-stranded alpha helix structure - **Not True** (RNA is usually single-stranded)

### Conclusion
The statement that is not true about RNA is that it has always a double-stranded alpha helix structure. Therefore, this is the correct answer to the question.

**Final Answer:** The statement that is not true about RNA is that it has always a double-stranded alpha helix structure.