Cell signaling follows the chronological order A, D, C (Reception → Transduction → Response). “Generation of signal (B)” precedes reception as the ligand production step, but the core pathway among listed options starts with reception, making B, A, D, C correct.

Cell Signaling Pathway Steps

Cell signaling enables intercellular communication via ligands (e.g., hormones, neurotransmitters). The standard three-stage model—reception, transduction, response—occurs after signal generation.

Correct Chronology: B → A → D → C

• B. Generation of signal: Signaling cell produces ligand (first overall step).

• A. Reception: Target cell receptor binds ligand, often causing conformational change.

• D. Transduction: Intracellular relay (second messengers like cAMP, phosphorylation cascades) amplifies signal.

• C. Response: Cellular change (gene expression, enzyme activation, cytoskeletal rearrangement).

Option Analysis

Cell signalling steps chronological order is vital for NEET/GATE Life Sciences, covering the four-phase process from ligand generation to cellular response in intercellular communication.

Complete Pathway Breakdown

1. Generation of signal (B): Autocrine/paracrine/endocrine ligands released.

2. Reception (A): GPCR/RTK binding initiates pathway (e.g., epinephrine → β-adrenergic receptor).

3. Transduction (D): Cascade amplification (adenylyl cyclase → cAMP → PKA).

4. Response (C): Glycogen breakdown, ion channel opening, transcription.

Exam Strategy

Standard textbook order (reception-transduction-response) omits B, but question includes it logically first. Examples: Insulin (RTK), cAMP (GPCR).