Overview of Cell Communication
A ______ is the signaling molecule that binds to a receptor.
Ligand
When cells communicate through direct physical interaction of membrane molecules, it is called ______ signaling.
Direct contact
The first step of cell signaling is called ______.
Reception
A signal transduction pathway usually involves a series of ______ reactions.
molecular
The final step of cell signaling is called the cellular ______.
What is signal transduction?
Signal transduction is the process that converts information from a signal into a cellular response.
What is paracrine signaling?
Paracrine signaling occurs when cells release signaling molecules that diffuse through extracellular fluid to nearby cells.
What happens when a ligand binds to a receptor?
The receptor changes shape and activates the signal transduction pathway.
Why are signal transduction pathways important?
They transmit and amplify the signal inside the cell to produce a response.
What are two types of cellular responses?
Changes in gene expression and changes in protein activity.
The molecule that receives a signal is called a ______.
Receptor Protein
______ signaling involves hormones traveling through the circulatory system.
Endocrine
Receptors bind ligands based on ______ shape.
complementary
Many pathways involve activation of ______ proteins.
Relay or signaling
Some signals activate ______ to turn genes on or off.
transcription factors
Why do cells only respond to certain signals?
Cells respond only to signals for which they have specific receptors.
Which type of signaling is commonly used by neurons?
Synaptic signaling.
Where are many receptors located?
On the plasma membrane of the cell.
What is signal amplification?
It is when one signal activates many molecules, increasing the strength of the response.
Why must signaling pathways be regulated?
To ensure cells respond appropriately and avoid excessive or incorrect responses.
A ligand binds to a receptor forming a ______.
Receptor-ligand complex
Paracrine signals usually have ______ effects.
Short-lived or local
The binding of a ligand often causes a ______ change in the receptor.
conformational (shape)
The pathway that carries the signal inside the cell is called the ______ pathway.
Signal transduction
Cell communication is essential for coordination in ______ organisms.
multicellular