Among the following, the molecule that would experience least resistance for entering a cell would be

Options

A. NaCl
B. Glucose
C. Fatty acid
D. Amino acid

Answer

To determine which molecule would experience the least resistance when entering a cell, we need to analyze the transport mechanisms involved for each option provided. Here’s a step-by-step solution:

### Step 1: Understand the types of transport mechanisms
Cells utilize different mechanisms to transport molecules across their membranes. The primary mechanisms include:
- **Passive Diffusion**: Molecules move across the membrane without the need for energy, typically down their concentration gradient.
- **Facilitated Diffusion**: Molecules require specific transmembrane proteins to help them cross the membrane, also moving down their concentration gradient.
- **Active Transport**: Molecules are moved against their concentration gradient, requiring energy.

### Step 2: Analyze the options
Assuming the options include molecules like NaCl, glucose, amino acids, and fatty acids, we can categorize them based on their transport mechanisms:
- **NaCl (Sodium Chloride)**: Typically requires facilitated diffusion or active transport.
- **Glucose**: Generally enters cells through facilitated diffusion using specific transporters.
- **Amino Acids**: Also enter via facilitated diffusion or active transport.
- **Fatty Acids**: Can enter cells through passive diffusion due to their lipid-soluble nature.

### Step 3: Determine which molecule experiences the least resistance
Since fatty acids can pass through the lipid bilayer of the cell membrane via passive diffusion, they would experience the least resistance compared to the other molecules, which require facilitated diffusion or active transport.

### Conclusion
The molecule that would experience the least resistance for entering a cell is **fatty acids**.