Unit 4 · 4.1 — Cell Communication [cite: 9, 28]

Everything to learn here

• Concept: Cells communicate via direct physical contact (e.g., gap junctions, plasmodesmata) or via chemical signals secreted over short (paracrine) and long (endocrine) distances [cite: 13, 14].
• Vocabulary: Ligand — a primary signaling molecule that binds with extreme specificity to a receptor site on another molecule [cite: 13, 14].
• Vocabulary: Target Cell — the specific cell equipped with the correct receptor protein required to receive and act upon a specific chemical signal [cite: 14].
• Concept: Cells communicate using diverse signals such as neurotransmitters, bacterial quorum sensing molecules, and embryonic morphogens.
• Concept: Long-distance signaling involves the release of chemical messengers that travel through the body to reach specific target cells.

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