cell communication 🧫

Gene Expression

Increasing or decreasing specific protein production.

Activation (Gene Expression)

Protein production increases.

Suppression (Gene Expression)

Protein production decreases.

Signaling Molecules

Non-polar, hydrophobic; regulate gene expression.

mRNA

Directs protein synthesis.

Metabolism

Sum of all cell chemical reactions.

Catabolic Pathways

Breaks down large molecules.

Anabolic Pathways

Builds large molecules.

Inhibitors

Block enzyme function.

Growth Factors

Signals regulating cell growth.

Apoptosis

Controlled cell death.

Signal Termination

Enzymatic breakdown of ligands.

Protein Kinases

Activate proteins by adding phosphates.

Phosphatases

Deactivate proteins by removing phosphates.

Adenylyl Cyclase

Converts ATP to cyclic AMP (active).

Phosphodiesterase

Changes cyclic AMP to AMP (inactive).

Quorum Sensing

Communication for coordinated behaviors.

Quorum

Sufficient cell density for actions

Intercellular signaling

Communication between cells where one cell sends a signal and another receives it.

Intracellular signaling

Communication within a single cell, like a neuron's electrical signal.

Ligand

A signaling molecule, like a hormone.

Target cell

Cell that receives a signal, with receptors for that signal.

Receptors

Proteins on a cell that bind signals and start a response.

Autocrine

Cell signaling to itself.

Gap Junctions

Direct channels connecting cells, allowing signals to pass directly.

Paracrine

Signaling to nearby cells.

Endocrine

Long-distance signaling via hormones in the bloodstream.

Hydrophobic hormones

Hormones that can go directly into cells.

Hydrophilic hormones

Hormones that need to bind to receptors on the cell surface.

Second messengers

Molecules that spread a signal inside a cell after a receptor is activated.

Intracellular Receptors

Inside cell; binds to small, nonpolar molecules, controlling genes.

Hydrophobic Ligands

Small, nonpolar molecules that freely enter cells to bind receptors.

Hydrophilic Ligands

Molecules needing surface receptors to signal inside cells.

Ion Channel-Linked Receptors

Surface receptors that open to allow ions through when a ligand binds.

G Protein-Linked Receptors (G Protein Coupled Receptors)

Receptors with subunits; ligand binding activates alpha, starting cell response.

Kinases

Add phosphate to activate proteins.

Phosphatases

Remove phosphate to deactivate proteins.

Adenylyl Cyclase

Converts ATP to cAMP (second messenger).

Cyclic AMP (cAMP)

Second messenger; amplifies signals, affects heart rate, and breaks down glycogen.

Tyrosine Kinase Receptors

Surface receptors that phosphorylate tyrosine to signal inside.

Second Messengers

Amplify cell signals; includes cAMP, PIP2, IP3, DAG, and Ca^{2+}.

Compare Intracellular and Cell Surface Receptors

What are the differences between intracellular and cell surface receptors?

Compare Hydrophobic and Hydrophilic Ligands

What are the differences between hydrophobic and