Read the following statements regarding agarose gel electrophoresis and select the CORRECT ones.
I. The longest DNA fragments are nearest to the anode.
II. The matrix of the gel is a natural polymer obtained from seaweeds.
III The process is used to check the progression of restriction enzyme digestion.
IV. The fragments of DNA separated due to the sieving effect provided by agarose gel.

Options

A. I, II III and IV
B. III and IV only
C. II, III and IV only
D. I, II and III only

Answer

To determine the correct statements regarding agarose gel electrophoresis, let's analyze each statement step by step.

### Step 1: Analyze Statement I
**Statement I:** The longest DNA fragments are nearest to the anode.

- **Analysis:** This statement is incorrect. In agarose gel electrophoresis, DNA fragments move towards the anode (positive electrode) due to the negative charge of the DNA. However, the longer fragments migrate more slowly and therefore remain closer to the wells (starting point) of the gel. The shorter fragments, being able to move through the gel matrix more easily, travel further and are found nearer to the anode.

**Hint:** Remember that DNA fragments separate based on size, with smaller fragments moving faster than larger ones.

### Step 2: Analyze Statement II
**Statement II:** The matrix of the gel is a natural polymer obtained from seaweeds.

- **Analysis:** This statement is correct. Agarose, the material used to make the gel for electrophoresis, is derived from agar, which is obtained from certain types of seaweed. Agarose gel is indeed a natural polymer.

**Hint:** Think about the source of agarose and its natural origins.

### Step 3: Analyze Statement III
**Statement III:** The process is used to check the progression of restriction enzyme digestion.

- **Analysis:** This statement is also correct. Agarose gel electrophoresis is commonly used to analyze the results of restriction enzyme digestion. By running the digested DNA on a gel, one can visualize the fragments and determine whether the digestion has occurred as expected.

**Hint:** Consider how scientists verify the effectiveness of restriction enzymes.

### Step 4: Analyze Statement IV
**Statement IV:** The fragments of DNA are separated due to the sieving effect provided by agarose gel.

- **Analysis:** This statement is correct. The agarose gel acts as a sieve, allowing smaller DNA fragments to pass through more easily than larger ones. This sieving effect is what enables the separation of DNA fragments based on size.

**Hint:** Visualize how a sieve works to separate different sizes of particles.

### Conclusion
Based on the analysis:
- Statement I is incorrect.
- Statements II, III, and IV are correct.

Thus, the correct statements regarding agarose gel electrophoresis are II, III, and IV.

### Final Answer
The correct statements are:
- II: The matrix of the gel is a natural polymer obtained from seaweeds.
- III: The process is used to check the progression of restriction enzyme digestion.
- IV: The fragments of DNA separated due to the sieving effect provided by agarose gel.