Cell biologyLesson 1 of 2 in the course Cell Communication

Receptor Signaling Pathways and Second Messengers

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

When a signaling molecule binds to a cell-surface receptor, the message must be relayed from the cell’s exterior to components inside the cell. This lesson explains how that relay begins and how it develops into a signaling pathway.

Signal transduction is the continuation of a signal from a receptor through the cell membrane and into the cytoplasm. In this unit, signal transduction begins when a ligand binds to a cell-surface receptor. The receptor’s shape changes, and this conformational change can affect its intracellular domain or proteins associated with that domain.

All flashcards

What is signal transduction?
The transmission of a receptor-initiated signal into the cell, where it can trigger further events.
How can receptor dimerization activate intracellular signaling?
Joining two receptors brings their intracellular domains close together, allowing them or associated proteins to become activated.
What is signal integration?
The convergence of signals from two or more cell-surface receptors to activate the same cellular response.
How does a signaling cascade amplify a signal?
Activated components can stimulate many downstream molecules, increasing the response at successive steps.
What are second messengers?
Small molecules or ions that propagate a signal inside a cell after receptor activation.

Quiz questions

  1. Why can phosphorylation have different effects on different target proteins?Answer: Its effect depends on the target protein and the site that is modified.
  2. Which enzyme synthesizes cyclic AMP from ATP?Answer: Adenylyl cyclase
  3. What does phospholipase C produce by cleaving PIP₂?Answer: DAG and IP₃
  4. Where does DAG act to promote signaling?Answer: At the plasma membrane, where it activates protein kinase C.
  5. In pancreatic β-cells, what response can increased cytoplasmic calcium promote?Answer: Insulin release

Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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