Read the following statements and select the correct ones.
(i) Electrophoresis is a technique used for the separation of molecules based on their size and charge.
(ii) Plasmids are extra-chromosomal, self-replicating, usually circular, double stranded DNA molecules found naturally in many bacteria and also in some yeast,.
(iii) It is not advisable to use an exonuclease enzyme while producing a recombinant DNA molecule.
(iv) In EcoRl, the roman numberal I indicates that it was the first enzyme isolated from E.coli
A) (i) and (ii)
B) (iii) and (iv)
C) (i),(ii) and (iv)
D) (i),(ii),(iii) and (iv)

Options

A. A) (i) and (ii)
B. B) (iii) and (iv)
C. C) (i),(ii) and (iv)
D. D) (i),(ii),(iii) and (iv)

Answer

To solve the question, we need to evaluate each of the four statements provided and determine their correctness. Here’s a step-by-step breakdown:

### Step 1: Analyze Statement (i)
**Statement:** Electrophoresis is a technique used for the separation of molecules based on their size and charge.
**Evaluation:** This statement is correct. Electrophoresis is indeed a method used to separate biomolecules, such as DNA, RNA, and proteins, based on their size and charge.

### Step 2: Analyze Statement (ii)
**Statement:** Plasmids are extra-chromosomal, self-replicating, usually circular, double-stranded DNA molecules found naturally in many bacteria and also in some yeast.
**Evaluation:** This statement is also correct. Plasmids are small, circular DNA molecules that replicate independently of chromosomal DNA and are commonly found in bacteria and some yeast.

### Step 3: Analyze Statement (iii)
**Statement:** It is not advisable to use an exonuclease enzyme while producing a recombinant DNA molecule.
**Evaluation:** This statement is correct. Exonucleases degrade nucleic acids from the ends, which can lead to the loss of important sequences needed for recombinant DNA technology. Therefore, their use is generally avoided in this context.

### Step 4: Analyze Statement (iv)
**Statement:** In EcoR1, the Roman numeral I indicates that it was the first enzyme isolated from E. coli.
**Evaluation:** This statement is correct. The Roman numeral in the name of restriction enzymes indicates the order of discovery, and EcoR1 was indeed the first enzyme isolated from E. coli.

### Conclusion
Since all four statements are correct, the correct answer to the question is:
**Option D: (i), (ii), (iii), and (iv)**.

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