Question

When a cell secretes a signaling molecule that binds to receptors on neighboring cells as well as the cell itself, this is called _________ signaling. a. direct intercellular b. contact-dependent c. autocrine d. paracrine e. endocrine

Short answer

The type of signaling where a cell secretes a molecule that binds to receptors on neighboring cells as well as the cell itself is called autocrine (Answer: c).

Step-by-step solution

Recall the definitions of different types of cell signaling

There are different types of cell signaling - direct intercellular, contact-dependent, autocrine, paracrine, endocrine. Let's recall their definitions.

Find the correct type of signaling

In autocrine signaling, cells secrete signaling molecules that bind to their own cell surface receptors. This matches with the provided description in the exercise.

Key concepts

Autocrine Signaling

Autocrine signaling is a form of cell communication that is akin to a cell talking to itself. Imagine a scenario where a cell sends out a message in the form of a chemical signal, and instead of reaching out to distant targets, the signal loops back to the very cell that sent it. This internal dialogue happens when a cell releases signaling molecules that can bind to receptors on its own surface, often leading to a response within that same cell.

In the realm of biology, autocrine signaling serves a number of critical roles. It helps cells in gauging their environment and making pivotal decisions such as whether to divide or differentiate into a new cell type. This form of signaling is particularly crucial in the immune system, where it can regulate the response of immune cells, and in development, where it guides cells to mature in a specific way. It's important for students to understand that autocrine signaling is somewhat self-reflective, in that it enables cells to modify their behavior based on their own signals.

Cell Communication

Cell communication is a cornerstone of all biological processes within multicellular organisms. It's all about how cells talk to each other to maintain harmony and balance in the body. To envision cell communication, picture a busy city where each individual has a specific role, and they all need to coordinate and share information to keep the city functioning smoothly. Cells do much the same thing using a variety of signaling methods, including autocrine, paracrine, endocrine, and more, to control and direct each other's actions.

An essential aspect of cell communication is the specific receptor-ligand interactions. Like a key to a lock, signaling molecules (ligands) must fit perfectly into their respective receptors on the target cell to relay their message. Each form of signaling has its own distance range: autocrine within the same cell, paracrine for nearby cells, and endocrine for cells far away, with hormones traveling through the bloodstream. Understanding these varied communication modes is crucial for students as it forms the basis of how organisms develop, respond to the environment, and maintain homeostasis.

Signaling Molecules

Signaling molecules are the body's very own postal service, delivering messages from one cell to another to coordinate bodily functions. These molecules are diverse and can be proteins, peptides, amino acids, steroids, or gases, each with a specific message and destination. They travel to different locations to deliver their instructions, whether that be within the same cell, to a neighbour, or all the way across the body.

Crucial to this concept is the idea that signaling molecules must be compatible with the receptors on the target cells — they must 'fit' to convey their message. This specificity ensures that each signaling molecule triggers the appropriate response, be it growth, division, death, or any of the myriad processes that cells are programmed to perform. A solid grasp of signaling molecules and their functions gives students a deeper understanding of the highly coordinated nature of biological systems and is fundamental to studies in cell biology, physiology, and medicine.