all unjt 3

Intracellular signaling

Signaling that occurs within a single cell.

Intercellular signaling

Signaling that occurs between cells in a multicellular organism.

Reception

The first stage of cell signaling where a chemical signal (ligand) binds to receptor protein on the target cell.

Transduction

The second stage of cell signaling where the binding of a ligand causes a shape change in the receptor, initiating internal changes.

Response

The third stage of cell signaling where the transduced signal triggers a specific cellular response.

Local Signaling

Communication that occurs over short distances between cells.

Autocrine signaling

Signaling where the signaling cell also responds to the signaling molecule it releases.

Direct Contact: Cell (gap) junctions

Signaling through direct contact where cells are adjacent to each other.

Direct Contact: Cell-cell recognition

Signaling through direct contact involving non-soluble ligands.

Paracrine signaling

Signaling between cells that are very close together, where ligands diffuse.

Synaptic signaling

A type of signaling that occurs in nerve cells where neurotransmitters are secreted into the synapse.

Long-distance signaling

Communication in multicellular organisms through hormonal (endocrine) signaling, where signals travel via the bloodstream.

Ligand

A signaling molecule that binds to a specific receptor.

Receptor

A protein that binds to a ligand and changes shape as a result.

Cell-surface (transmembrane) receptors

Receptors located on the plasma membrane that bind to water-soluble signal molecules.

Internal receptors

Receptors found inside the cell that bind to hydrophobic, small, non-polar molecules.

Ion Channel Receptors

Receptors that open a gate to allow ions to flow through the membrane in response to a signaling molecule.

G-Protein-Coupled Receptors (GPCRs)

Receptors that bind to G proteins and span the membrane with seven alpha helices.

Enzyme-Linked Receptors (Receptor Tyrosine Kinases)

Receptors that trigger multiple pathways at once and catalyze the transfer of phosphate.

Cholera

A toxin produced by Vibrio cholerae that disrupts G-protein signaling.

Amplification

The enhancement of signal strength in multistep cellular processes.

Coordination

Ensuring multiple signaling pathways can be activated simultaneously.

Regulation

Controlling the extent and duration of a cellular signal.

Cascade of activation

Sequential activation of proteins in a signaling pathway starting from the initial signal.

Protein Kinases

Enzymes that transfer phosphate groups from ATP to other molecules, modifying their activity.

Cytoplasmic Kinases

Kinases that typically phosphorylate serine or threonine residues in target proteins.

Ca²⁺

A widely-used second messenger involved in signal transduction and cellular processes.

Second messengers

Small, non-protein molecules or ions that participate in signal transduction and signal amplification.

Cyclic AMP (cAMP)

A second messenger that activates cAMP-dependent kinases in G-protein signaling pathways.

cGMP

A second messenger that plays a role in various cellular processes.

Apoptosis

Programmed cell death characterized by a controlled process leading to fragmentation of the cell.

Molecular Basis of Apoptosis

Involves signaling pathways that activate nucleases and proteases facilitating cell death.

Signal Termination

Mechanisms that inactivate signals to reset the signaling pathways.

Lapatinib (Tykerb)

An inhibitor that targets HER2, a receptor tyrosine kinase in breast cancer treatments.

Quorum Sensing

Process allowing bacteria to determine population density through chemical signaling.

Autoinducers

Signaling molecules secreted by bacteria to communicate with others of the same kind.

Biofilm

A community of microbes that exchange chemical signals and coordinate behaviors like virulence.

Cell Theory

A biological principle stating that all cells arise from pre-existing cells.

Cell Division

The process by which a parent cell divides into two or more daughter cells.

Genome

The complete set of genes or genetic material present in a cell.

Chromosomes

Structures that contain DNA within cells, existing in either condensed or uncondensed forms.

Chromatin

A complex of DNA and proteins that forms chromosomes in eukaryotic cells.

Somatic Cells

Diploid cells that make up most of the human body, excluding gametes.

Gametes

Haploid cells (egg and sperm) involved in sexual reproduction.

Karyotype

A visual representation of an organism's complete set of chromosomes.