Study the following statements regarding recombinant DNA technology and select the incorrect ones.
(i) Taq polymerase extends the primers using the nucleotides provided in the reaction.
(ii) Antibiotic resistance genes are considered as desirable genes in recombinant DNA technology.
(iii) DNA fragments are separated according to their charge only, in agarose gel electrophoresis.
(iv) Transformation is a procedure through which a piece of DNA is integrated in to the genome of a host bacterium.
(v) To produce higher yields of a desired protein, host cells can be multiplied in a continuous culture.
(vi) Downstream processing is one of the steps of polymerase chain reaction.

Options

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

Explanation

To determine which statements regarding recombinant DNA technology are incorrect, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement (i):** "Taq polymerase extends the primers using the nucleotides provided in the reaction."
- **Analysis:** This statement is correct. Taq polymerase is an enzyme used in PCR (Polymerase Chain Reaction) that synthesizes new DNA strands by adding nucleotides to the primers.

2. **Statement (ii):** "Antibiotic resistance genes are considered as desirable genes in recombinant DNA technology."
- **Analysis:** This statement is incorrect. Antibiotic resistance genes are used as selectable markers, not as desirable genes. Desirable genes refer to the genes of interest that researchers want to clone or express.

3. **Statement (iii):** "DNA fragments are separated according to their charge only, in agarose gel electrophoresis."
- **Analysis:** This statement is incorrect. In agarose gel electrophoresis, DNA fragments are separated based on both their charge and size. The charge allows them to migrate through the gel, while size determines how quickly they move.

4. **Statement (iv):** "Transformation is a procedure through which a piece of DNA is integrated into the genome of a host bacterium."
- **Analysis:** This statement is correct. Transformation is the process by which a bacterium takes up foreign DNA from its environment and incorporates it into its genome.

5. **Statement (v):** "To produce higher yields of a desired protein, host cells can be multiplied in a continuous culture."
- **Analysis:** This statement is correct. Continuous culture allows for the sustained growth of microorganisms, which can lead to higher yields of the desired protein.

6. **Statement (vi):** "Downstream processing is one of the steps of polymerase chain reaction."
- **Analysis:** This statement is incorrect. Downstream processing refers to the purification and recovery of products after fermentation or expression, and it is not a step in the PCR process, which consists of denaturation, annealing, and extension.

### Summary of Incorrect Statements:
- The incorrect statements are:
- Statement (ii)
- Statement (iii)
- Statement (vi)

### Final Answer:
The incorrect statements are (ii), (iii), and (vi).

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