AP BIOLOGY

Detailed explanation-1: -Paracrine signaling. Often, cells that are near one another communicate through the release of chemical messengers (ligands that can diffuse through the space between the cells). This type of signaling, in which cells communicate over relatively short distances, is known as paracrine signaling.

Detailed explanation-2: -There are four categories of chemical signaling found in multicellular organisms: paracrine signaling, endocrine signaling, autocrine signaling, and direct signaling across gap junctions.

Detailed explanation-3: -Cytokines. Cytokines are a very important set of proteins in the body. These small proteins serve as messengers for the immune system. They are produced in response to a threat and represent the communication network for the immune system.

Detailed explanation-4: -Cell signaling is the process of communication between the cells of the body. It follows a ‘simple’ three-step sequence. Let’s imagine that cell A wants to get a message to cell B. Cell A secretes molecules that carry this message or signal.

Detailed explanation-5: -The three main ways for cells to connect with each other are: gap junctions, tight junctions, and desmosomes. These types of junctions have different purposes, and are found in different places.