16 Questions
Which proteins act as molecular switches in intracellular cell signaling?
GEF- guanine nucleotide exchange factor
Which type of receptors convert chemical signals into electrical ones?
Ion-Channel–Coupled Receptors
What type of receptors have intrinsic enzyme activity or associate with enzymes?
Enzyme Coupled Receptors
Which molecules mediate responses to diverse extracellular signals like hormones and neurotransmitters?
G-proteins
What are the largest family of cell surface receptors?
G-Protein–Coupled Receptors
Which type of cell signaling involves a membrane-bound signal molecule that requires close proximity between cells?
Contact-dependent signaling
Which statement best describes the role of receptors in cell signaling?
Receptors relay signals via intracellular signaling
What is the primary factor that determines how a cell will respond to a signal?
The type of receptor molecules on the cell membrane
Which type of cell signaling involves signal molecules that travel long distances but target specific cells?
Endocrine signaling
How do signal molecules regulate the behavior of a cell?
Signal molecules work in combinations to regulate cell behavior
What is the process by which cells convert an extracellular signal into an intracellular signal called?
Signal Transduction
Which of the following is NOT an example of an extracellular molecule used as a signal?
DNA
What type of signaling involves hormones traveling long distances from endocrine cells to target cells?
Endocrine Signaling
What type of signaling involves signaling molecules that are only received by neighboring cells?
Paracrine Signaling
Which of the following is NOT a common type of receptor used in cell signaling?
Transcription Factor-Linked Receptors
Which of the following is NOT an example of a dissolved gas used in cell signaling?
Oxygen
Study Notes
General Principles of Cell Signaling
- Cell signaling involves converting information from one form to another through signal transduction.
- Signal transduction is the process of converting an extracellular signal into an intracellular signal.
- Cells respond to a limited set of signals, and different types of cells respond to the same signal in different ways.
Cell-Surface Receptors
- Cell-surface receptors fall into three main classes:
- Ion-channel–coupled receptors (convert chemical signals into electrical ones)
- G-protein–coupled receptors (activate G-proteins, which then activate enzymes or ion channel receptors)
- Enzyme-coupled receptors (have intrinsic enzyme activity or associate with enzymes)
G-Protein-Coupled Receptors
- G-protein-coupled receptors are the largest family of cell surface receptors.
- They have a single polypeptide, seven-pass transmembrane receptor protein structure.
- They mediate responses to diverse extracellular signals, such as hormones, local mediators, and neurotransmitters.
Signaling Pathways
- Some intracellular signaling proteins act as molecular switches.
- Phosphorylation and dephosphorylation are key mechanisms in signaling pathways.
- GTP-GDP exchange is another important mechanism in signaling pathways.
Types of Signaling
- Autocrine signaling: signal is released by the cell and acts on the same cell.
- Paracrine signaling: signal is released by a cell and acts on neighboring cells.
- Endocrine signaling: signal is released by endocrine cells and travels long distances to reach target cells.
- Contact-dependent signaling: signal is transmitted through membrane-bound signal molecules, and the target cell must be very close to the signaling cell.
Cell Communication
- Cells have four basic styles of communication: autocrine, paracrine, endocrine, and contact-dependent signaling.
- Each cell responds to a limited set of signals, and different types of cells respond to the same signal in different ways.
- Signal molecules work in combinations to regulate the behavior of the cell.
Test your knowledge on cell signaling, including general principles, communication methods, receptors, and signal transduction. Learn about the two classes of signaling molecules and how cells sense and respond to their environment.
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