Read the following statements regardingribosomes:-
(i) 0.001 M concentration of calcium ion is required for the binding of subunits
(ii) Also known as organelle within organelle.
(iii)5 S r-RNA is common to both 70 S and 80 S ribosomes.
(iv)All the components of ribosome are synthesised in nucleolus. Which of the above statements are incorrect?

Options

A. (i) & (iv)
B. (i) & (ii)
C. (ii) & (iii)
D. (ii) & (iv)

Answer

To determine which statements regarding ribosomes are incorrect, let's evaluate each statement step by step:

1. **Statement (i)**: "0.001 M concentration of calcium ion is required for the binding of subunits."
- **Evaluation**: Ribosomes consist of two subunits (large and small) that require magnesium ions (Mg²⁺) for their binding, not calcium ions (Ca²⁺). The correct concentration of magnesium ions needed is typically around 0.01 M. Therefore, this statement is **incorrect**.

2. **Statement (ii)**: "Also known as organelle within organelle."
- **Evaluation**: Ribosomes are often referred to as "organelle within organelle" because they are found within larger organelles such as mitochondria and chloroplasts, as well as being associated with the rough endoplasmic reticulum. This statement is **correct**.

3. **Statement (iii)**: "5 S r-RNA is common to both 70 S and 80 S ribosomes."
- **Evaluation**: The 5S rRNA is indeed a component of both 70S ribosomes (found in prokaryotes) and 80S ribosomes (found in eukaryotes). Therefore, this statement is **correct**.

4. **Statement (iv)**: "All the components of ribosome are synthesized in nucleolus."
- **Evaluation**: In eukaryotes, the nucleolus is responsible for synthesizing rRNA and assembling ribosomal subunits. However, in prokaryotes, ribosomes are assembled in the cytoplasm since they lack a defined nucleus and nucleolus. Thus, this statement is **incorrect**.

**Conclusion**: The incorrect statements are (i) and (iv).

### Final Answer:
The incorrect statements regarding ribosomes are (i) and (iv).