Which of the following statements are correct?
1. Starch forms helical secondary structures while cellulose doesn't have complex helices.
2. Palmitic acid has 14- `CH_2` groups in its structure.
3. Maltose is a disaccharide made up of glucose and fructose.
4. The number of carbon and oxygen atoms present in glucose is less than those present in ribose.

Options

A. 1 and 2
B. 3 and 4
C. 1, 2 and 3
D. 1, 2, 3 and 4

Answer

To determine which of the statements provided are correct, let's analyze each statement step by step.

### Step 1: Analyze Statement 1
**Statement:** Starch forms helical secondary structures while cellulose doesn't have complex helices.

**Analysis:**
- Starch is a polysaccharide that consists of two components: amylose and amylopectin. Amylose has a helical structure, and amylopectin has branched structures, both of which can trap iodine, resulting in a blue-black color.
- Cellulose, on the other hand, is a linear polysaccharide made up of glucose units linked together. It does not form helices but rather has a straight-chain structure.

**Conclusion:** This statement is correct.

### Step 2: Analyze Statement 2
**Statement:** Palmitic acid has 14- `CH_2` groups in its structure.

**Analysis:**
- Palmitic acid is a saturated fatty acid with a total of 16 carbon atoms. The structure can be represented as CH3-(CH2)14-COOH.
- Out of the 16 carbon atoms, 14 are in the form of `CH2` groups (the two terminal carbons are CH3 and COOH).

**Conclusion:** This statement is correct.

### Step 3: Analyze Statement 3
**Statement:** Maltose is a disaccharide made up of glucose and fructose.

**Analysis:**
- Maltose is actually composed of two glucose molecules linked together. It does not contain fructose.

**Conclusion:** This statement is incorrect.

### Step 4: Analyze Statement 4
**Statement:** The number of carbon and oxygen atoms present in glucose is less than those present in ribose.

**Analysis:**
- Glucose has the formula C6H12O6, while ribose has the formula C5H10O5.
- Glucose has more carbon (6 vs. 5) and more oxygen (6 vs. 5) atoms than ribose.

**Conclusion:** This statement is incorrect.

### Final Conclusion:
- The correct statements are **1 and 2**. Therefore, the answer is that statements 1 and 2 are correct.

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