Cell Signaling Mechanisms Quiz

Cells selectively respond to signals by activating specific receptors and intracellular molecules, leading to fast or slow responses, impacting gene expression or protein function.

Signal molecules vary in size, hydrophobicity, and stability, influencing how they travel and interact with target cells.

Cell-surface receptors that allow ions to flow across the membrane, changing the cell's electrical activity in response to a ligand.

Signal transmission between nearby cells or a cell to itself.

Cell-surface receptors that activate associated G-proteins, triggering intracellular signaling cascades.

Receptors located inside the cell, often responding to hydrophobic signaling molecules.

Signal transmission between distant cells using the bloodstream or nervous system.

Receptors located on the cell surface, responding to a wide range of extracellular signaling molecules.

Reactions in cells triggered by signals; can be fast or slow.

Converting extracellular signals into intracellular signals within a cell.

Different receptors are categorized based on the specific transduction mechanisms they use when activated by a ligand.

How a cell determines how to respond to a specific signal.

Cells experience multiple signals simultaneously.

Cells generally only respond to a limited/specific set of signals.

A rapid physiological response to perceived danger.

Drugs that increase intracellular cAMP levels.

A toxin that inhibits the GTP to GDP switch, interfering with signal deactivation, leading to cAMP accumulation and salt secretion.

G-protein coupled receptors, which are cell surface receptors that activate intracellular signaling pathways.

An enzyme that breaks down phospholipids into second messengers (DAG and IP3).

A lipid second messenger that activates protein kinase C (PKC).

A water-soluble second messenger that triggers calcium release from the endoplasmic reticulum.

A crucial cellular trigger activating many calcium-dependent enzymes, not only activated by GPCRs.

The cell's ability to determine how a particular signal should be interpreted.

Understanding how cells communicate is crucial for understanding how organisms function. It allows for coordinated responses to internal and external changes, ensuring proper tissue development and organism survival.

G-protein–coupled receptors (GPCRs) are a type of cell surface receptor that activate associated G-proteins, triggering intracellular signaling cascades.

Signal transduction is the process of converting extracellular signals into intracellular signals within a cell. This involves a series of steps that amplify and relay the signal.

The 'fight-or-flight' response is a rapid physiological response to perceived danger, characterized by increased heart rate, breathing, and adrenaline release.

Robert Lefkowitz and Brian Kobilka won the 2012 Nobel Prize in Chemistry for their groundbreaking discoveries about G-protein–coupled receptors, revealing how they work.

Molecules that block receptor responses by binding to receptors, preventing the activation of the receptor.

The process by which cells communicate with each other, coordinating their activities.

Signaling pathways that take place inside a cell, often in response to signals from outside the cell.

Cell surface receptors that, upon binding to a signaling molecule, activate an enzyme that initiates a signaling cascade.

Receptors that directly activate or associate with an enzyme upon binding to an extracellular signal.

A family of enzyme-coupled receptors that are themselves enzymes, specifically tyrosine kinases, phosphorylating tyrosine residues on target proteins.

RTKs typically consist of an extracellular ligand-binding domain, a transmembrane α-helix, and an intracellular tyrosine kinase domain.

Ligand binding to an RTK leads to receptor dimerization (pairing), followed by autophosphorylation, activating the intracellular kinase domain.

RTKs regulate a wide range of cellular processes, including cell growth, differentiation, and survival, often triggered by growth factors.

Phosphorylation is a key mechanism for RTK activation and further signaling pathways, acting as a molecular 'switch'.

A signaling pathway that involves a receptor associated with a separate enzyme, Janus kinase (JAK), leading to phosphorylation of STAT proteins that then act as transcription factors.

Both enzyme-coupled receptors and GPCRs are frequently targets for pharmaceuticals, offering potential for therapeutic intervention due to their critical role in signaling pathways.