Biochemical Signaling

These flashcards provide key vocabulary terms and definitions related to biochemical signaling, encompassing signal transduction processes, receptor types, and regulatory mechanisms involved in cellular communication.

Signal Transduction

The conversion of information into a chemical change.

Amplification

The process where one enzyme is activated by a signal receptor and catalyzes the activation of many molecules of another enzyme.

Signal Integration

The ability of a system to receive multiple signals and produce a unified response.

G Protein-Coupled Receptor (GPCR)

A large group of plasma membrane receptors with seven transmembrane helices that act through G proteins.

Phosphorylation

The addition of a phosphate group to a protein, which can toggle enzyme activity.

Ion Channel

A protein that allows the passage of ions through a membrane, often gated by a ligand or voltage.

Ligand

A signaling molecule that binds to a receptor to initiate a cellular response.

Second Messenger

A low molecular weight metabolite or inorganic ion that functions to activate or inhibit downstream targets.

Tyrosine Kinase

An enzyme that adds phosphate groups to tyrosine residues on proteins, often involved in signaling.

Autophosphorylation

The process by which a kinase phosphorylates itself, enhancing its activity.

Phospholipase C (PLC)

An enzyme that catalyzes the cleavage of PIP2, generating diacylglycerol and IP3.

cAMP (Cyclic AMP)

A second messenger that activates protein kinase A (PKA) and regulates various cellular processes.

GTPase

An enzyme that hydrolyzes GTP to GDP, playing a role in signal transduction.

Calmodulin (CaM)

A calcium-binding protein that regulates many enzymes through conformational changes.

Apoptosis

Programmed cell death, a mechanism by which cells control the timing of their own death.

Homeostasis

The maintenance of a stable internal environment in an organism.

Competition

A situation in which two signaling molecules bind to the same receptor, affecting the outcome.

Cancer

A disease characterized by uncontrolled cell division, often due to defective signaling.

Hormone Response Element (HRE)

Specific regulatory sequences in DNA that interact with receptor proteins after hormone binding.

Phosphorylated Residues

Tyrosine, serine, or threonine residues that are modified by the addition of phosphate groups.

Cyclic Nucleotide Phosphodiesterase

An enzyme that hydrolyzes cAMP and cGMP, regulating their levels.

Extracellular Signal

A signaling molecule that acts outside the cell, influencing cellular activity.

Receptor Tyrosine Kinase (RTK)

A family of cell surface receptors that mediate cellular responses by phosphorylating tyrosines.

MAPK Cascade

Signaling pathways that amplify the signals from growth factors and other mitogens.

Epinephrine

A hormone that increases blood glucose levels by binding to its GPCRs.

Insulin

A hormone that lowers blood glucose levels by promoting cellular uptake.

Protein Kinase A (PKA)

An enzyme activated by cAMP that phosphorylates target proteins.

Receptor-Enzyme

A receptor that has intrinsic enzyme activity, often functioning as a kinase.

Nuclear Receptor

Receptors located in the nucleus that regulate gene expression in response to hormone binding.

Tyrosine Phosphatase

An enzyme that removes phosphate groups from phosphorylated tyrosine residues.

Oncogenes

Mutant forms of genes that promote cell division and may lead to cancer.

Tumor Suppressor Genes

Genes that regulate cell division and inhibit tumor formation, often mutated in cancer.

Guanosine Triphosphate (GTP)

A nucleotide that functions as an energy source and signaling molecule in cellular processes.

Adenylyl Cyclase

An enzyme that converts ATP to cAMP, thus serving as an effector in GPCR signaling.

Phosphorylation Cascade

A series of reactions where one enzyme activates another through phosphorylation.

Cross Talk

Interactions between different signaling pathways that can affect cellular responses.

Ca2+ Channels

Ion channels that open or close in response to changes in calcium ion concentrations.

Cyclic GMP (cGMP)

A second messenger similar to cAMP, involved in signaling pathways.

Feedback Inhibition

A regulatory mechanism in which the output of a pathway inhibits its own production.

Transmembrane Protein

A protein that spans the membrane and plays a role in signaling or transport.

Ligand-Receptor Interaction

The binding of a signaling molecule to its specific receptor, initiating a signal transduction pathway.

Mitosis

A phase of the cell cycle where cell division occurs, resulting in two daughter cells.

Extracellular Matrix

A network of proteins and carbohydrates outside cells that provide structural and biochemical support.

Endoplasmic Reticulum

An organelle involved in protein folding and processing, and calcium storage.

Signaling Pathway

A series of molecular events initiated by a receptor interacting with a ligand.

Receptor-Mediated Endocytosis

The process by which cells internalize molecules by binding them to receptors.

Signal Specificity

The precise interaction between a signaling molecule and its receptor.

Protein Kinase

An enzyme that adds phosphate groups to proteins, altering their activity.

GTPase Activating Protein (GAP)

Proteins that stimulate GTPase activity and promote the inactivation of G proteins.

Insulin Receptor Substrate (IRS)

Proteins that mediate signals from insulin receptors to downstream pathways.

cAMP Response Element-Binding Protein (CREB)

A protein that binds to cAMP response elements in DNA and regulates gene expression.

Glucose Transporter (GLUT4)

A protein that facilitates glucose uptake in response to insulin signaling.