What are receptors ? Where are they located in the cell ?

Explanation

### Step-by-Step Solution:

**Step 1: Definition of Receptors**
Receptors are specialized proteins located in or on the surface of cells. They are crucial for the communication between cells and their environment. Receptors bind to specific signaling molecules, such as hormones or drugs, and facilitate the transmission of signals into the cell.

**Step 2: Function of Receptors**
When a signaling molecule binds to a receptor, it activates the receptor and triggers a response within the cell. This response can lead to various cellular activities, including cell growth, division, and other important biological processes. Essentially, receptors act as messengers that convey information from outside the cell to the inside.

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