Cell communication and cell cycle concepts

Short-distance communication example

Nerve cells release neurotransmitters, which attach immediately to the target cell

Long-distance communication example

Endocrine glands release hormones, which travel to the target cells through the bloodstream

Three stages of cell signaling

Reception, signal transduction, and response

How G-protein coupled receptors work

The ligand binds to the receptor protein, which activates a G-protein, which interacts with an ion channels or enzyme in the membrane

How ligand-gated channels work

The ligand binds to the receptor, which changes shape, letting ions through

Common parts of signal transduction pathways

Protein modification and phosphorylation cascades

Common second messengers

Cyclic AMP/cAMP and Ca+ ions

Cellular response examples

Growth and division, secretion of molecules, gene expression, protein synthesis, change in metabolism, cell death

Result of gene expression response

Transcription and translation are turned on or off

Cellular metabolism response example

Release of adrenaline causes the breakdown of glycogen into glucose for use in “fight or flight” response

Origin of most signals for cell division

Other cells

Signals for apoptosis examples

Damaged DNA and movement of a cell away from the extracellular matrix

Causes of changes in signal transduction pathways

Mutations, chemicals, change in structure of any signaling molecule

Negative feedback examples

Body temperature, water levels, glucose levels

Positive feedback examples

Blood clotting, contractions during childbirth