Plasmalemma is

Options

A. Permeable
B. Selectively permeable
C. Non-permeable
D. Semispermeable

Answer

To answer the question "Plasmalemma is:", we can follow these steps:

### Step 1: Define Plasmalemma
Plasmalemma, also known as the plasma membrane, is the outer boundary of a cell. It separates the internal contents of the cell from the external environment.

### Step 2: Describe the Composition
The plasmalemma is primarily composed of a phospholipid bilayer, which means it has two layers of phospholipids. These molecules have hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails.

### Step 3: Explain the Role of Proteins
Embedded within this phospholipid bilayer are various proteins. These proteins play crucial roles in the transport of substances across the membrane, including ions, water, and other solutes.

### Step 4: Determine the Permeability
The combination of the phospholipid bilayer and the embedded proteins gives the plasmalemma its permeability characteristics. It allows certain substances to pass through while restricting others.

### Step 5: Conclude the Nature of Plasmalemma
Given that the plasmalemma allows some substances to pass while blocking others, it is classified as semi-permeable. This means it selectively allows certain molecules to enter or exit the cell.

### Final Answer
Therefore, the correct answer to the question "Plasmalemma is:" is **D) semi-permeable**.

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