Which of the following statement regarding cillia is not correct ?

Answer

To determine which statement regarding cilia is not correct, we can analyze the provided statements step by step:

### Step 1: Understand the Structure of Cilia
Cilia are hair-like appendages found on the surface of many eukaryotic cells. They are composed of microtubules arranged in a specific pattern.

**Hint:** Cilia are made of microtubules and have a characteristic structure.

### Step 2: Identify the Composition of Cilia
The microtubules in cilia are primarily made of tubulin. The arrangement of these microtubules is typically in a "9 + 2" configuration, meaning there are nine doublet microtubules surrounding two central microtubules.

**Hint:** Remember the "9 + 2" arrangement of microtubules in cilia.

### Step 3: Function of Cilia
Cilia are involved in movement and locomotion. The beating of cilia is essential for their function, and this movement is powered by the protein dynein, which hydrolyzes ATP to provide the necessary energy.

**Hint:** Dynein is the key protein responsible for the movement of cilia.

### Step 4: Role of Calcium Ions
The question mentions that the organized beating of cilia is controlled by calcium ions. However, this is not accurate. The beating is primarily controlled by dynein and the energy derived from ATP, not calcium ions.

**Hint:** Focus on the role of dynein and ATP rather than calcium ions in ciliary movement.

### Conclusion
Based on the analysis, the statement that claims the organized beating of cilia is controlled by calcium ions is not correct. Instead, it is controlled by dynein, which uses ATP for energy.

**Final Answer:** The statement regarding cilia that is not correct is that their organized beating is controlled by calcium ions.