14D Transferring Information across Membranes

These flashcards cover vocabulary from Biochemistry Lecture #14, focusing on signal transduction mechanisms and key concepts related to receptor function.

Modularity

Adapt similar structures to respond to different signals.

Specificity

Specific receptor is responsive to a specific ligand.

Amplification

One ligand binding event outside a cell can activate thousands of enzymes inside a cell.

Termination

Mechanisms of turning off a signal in signal transduction.

G-Protein Coupled Receptors (GPCRs)

A class of receptors that activate G-proteins upon ligand binding.

Ligand

A molecule that binds to a receptor to initiate a biological response.

Epinephrine

A hormone that stimulates cAMP production and calcium influx in cells.

Second messengers

Molecules that mediate and amplify the signal transduced by a receptor.

Adenylate Cyclase

An enzyme activated by GPCRs that converts ATP to cAMP.

Phospholipase C

An enzyme that generates second messengers from membrane phospholipids.

Tyrosine Kinase

An enzyme that phosphorylates proteins on tyrosine residues, often activated by ligand binding to receptors.

Insulin

A peptide hormone that regulates glucose uptake and metabolism in cells.

Dimerization

The process where two receptor molecules come together to form a functional complex.

Auto-Phosphorylation

Self-activation of a kinase by adding a phosphate group to itself.

IRS-1

Insulin Receptor Substrate-1, a key factor in insulin signaling pathways.

PIP2

Phosphatidylinositol 4,5-bisphosphate, a membrane phospholipid involved in signaling.

PIP3

Phosphatidylinositol 3,4,5-trisphosphate, a second messenger that recruits kinases.

Glut4 transporters

Proteins that facilitate glucose uptake into cells, activated by insulin signaling.

Glucose uptake

The process of cells absorbing glucose from the bloodstream.

Signaling cascade

A series of biochemical events triggered by a receptor activation that leads to a cellular response.

Activation Loop

A structural element in kinases that must move to expose the active site for phosphorylation.

Phosphorylation

The addition of a phosphate group to a molecule, often regulating activity.

GTP

Guanosine triphosphate, a nucleotide that activates G-proteins.

GDP

Guanosine diphosphate, the inactive form of GTP.

Heterotrimeric G-Protein

A G-protein composed of three different subunits (alpha, beta, and gamma) that mediates GPCR signaling.

cAMP

Cyclic adenosine monophosphate, a second messenger involved in many signaling pathways.

Calcium influx

The movement of calcium ions into cells, often serving as a second messenger.

Insulin receptor

A receptor that binds insulin and initiates a signaling cascade for glucose uptake.