Read the following statements and select the incorrect ones.
(i) When the transformed cells on agar plates containing ampicillin are spread, both transformed and untransformed cells will grow.
(ii) Restriction enzymes are used in isolation and separation of DNA from other macromolecules.
(iii) Downstream processing is one of the steps of rDNA technology.
(iv) Disarmed pathogen vectors are also used in transfer of rDNA into the host.
a) (i) and (iii)
b) (iii) and (iv)
c) (i) and (iii)
d) (i) and (ii)

Options

A. a) (i) and (iii)
B. b) (iii) and (iv)
C. c) (i) and (iii)
D. d) (i) and (ii)

Explanation

To determine the incorrect statements from the given options, let's analyze each statement step by step:

1. **Statement (i)**: "When the transformed cells on agar plates containing ampicillin are spread, both transformed and untransformed cells will grow."
- **Analysis**: This statement is incorrect. In an agar plate containing ampicillin, only the transformed cells, which have taken up the plasmid containing the ampicillin resistance gene, will survive and grow. Untransformed cells do not have this resistance and will be killed by the ampicillin.

2. **Statement (ii)**: "Restriction enzymes are used in isolation and separation of DNA from other macromolecules."
- **Analysis**: This statement is also incorrect. Restriction enzymes are not used for the isolation and separation of DNA; rather, they are used to cut DNA at specific sequences. The separation of DNA from other macromolecules is typically done using techniques like centrifugation or precipitation, not restriction enzymes.

3. **Statement (iii)**: "Downstream processing is one of the steps of rDNA technology."
- **Analysis**: This statement is correct. Downstream processing refers to the purification and recovery of the product after the recombinant DNA technology processes, making it a valid step in rDNA technology.

4. **Statement (iv)**: "Disarmed pathogen vectors are also used in transfer of rDNA into the host."
- **Analysis**: This statement is correct. Disarmed pathogen vectors are indeed used to transfer recombinant DNA into host cells, as they can facilitate the uptake of DNA without causing disease.

**Conclusion**: The incorrect statements are (i) and (ii). Therefore, the correct answer is option **d) (i) and (ii)**.