AP Bio Insta-Review Topic 4.3*: Signal Transduction

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What is apoptosis?

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Programmed cell death.

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What is a transcription factor?

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A protein that binds to specific DNA sequences to turn on or off gene expression.

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What is signal transduction?

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The process by which a cell responds to external signals through a series of molecular events.

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What role do receptors play in signal transduction?

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Receptors are proteins that detect and bind to signaling molecules, initiating the signal transduction pathway.

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What is a ligand?

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A molecule that binds to a receptor to initiate a signal transduction pathway.

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What is the difference between endocrine and paracrine signaling?

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Endocrine signaling involves hormones traveling through the bloodstream to distant targets, while paracrine signaling involves local signaling between nearby cells.

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What is the function of G-proteins in signal transduction?

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G-proteins act as molecular switches that relay signals from activated receptors to target proteins inside the cell.

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What is the role of second messengers in signal transduction?

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Second messengers are small molecules that amplify and propagate the signal within the cell after the receptor is activated.

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What is the significance of phosphorylation in signal transduction?

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Phosphorylation is the addition of a phosphate group to a protein, which can change the protein's activity and function, often activating or deactivating signaling pathways.

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What is a feedback loop in biological systems?

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A feedback loop is a regulatory mechanism where the output of a process influences its own production, either enhancing (positive feedback) or inhibiting (negative feedback) the process.