CH.11: Cell-to-Cell Interactions

Cell-Cell Interactions

Communication and cooperation among multicellular organisms.

Plasma Membrane

Phospholipid bilayer with embedded proteins.

Integral Proteins

Proteins that span the membrane's bilayer.

Peripheral Proteins

Proteins attached to membrane surface.

Membrane Proteins

Proteins forming tight junctions between cells; Regulates transport and cell environment

Cytoskeletal Elements

Structures that support cell shape and organization.

Extracellular Structures

Components outside the cell membrane.

Signal Transduction

Process of converting a signal into a cellular response.

Glycoproteins

Proteins with carbohydrate chains for cell recognition.

Intercellular Joining

Connections between adjacent cell membranes.

Extracellular Matrix (ECM)

Network providing structural support to cells.

Cell Wall

Protective layer surrounding plant and prokaryotic cells.

Peptidoglycan

Polysaccharide forming bacterial cell walls.

S-layer

Protein coat forming archaea cell walls.

Fiber Composite

Material providing strength and structure in ECM.

Microfibrils

Cable-like structures in plant cell walls.

Pectin

Gelatinous polysaccharide keeping cell walls moist.

Turgor Pressure

Pressure from water inside plant cells.

Expansins

Proteins that facilitate plant cell growth.

Secondary Cell Wall

Additional layer providing strength to mature plant cells.

Lignin

Complex organic polymer in woody plant cells.

Middle Lamella

Pectin layer gluing adjacent plant cell walls.

Collagen

Fibrous protein providing structural support in ECM.

Proteoglycans

Proteins with polysaccharides, forming cartilage-like consistency.

Elastin

Protein allowing elasticity in lung tissue.

Integrins

Membrane proteins linking ECM to cytoskeleton.

Laminins

Cross-linking proteins in the ECM.

Cell Communication

Mechanisms allowing cells to exchange information.

Multicellularity

Organisms composed of multiple interconnected cells.

Cell-Cell Attachments

Structures binding cells together in tissues.

Epithelia

Tissues lining surfaces of organs and cavities.

Pectins

Gelatinous substances in middle lamella of plants.

Tight Junctions

Waterproof seals between adjacent animal cells.

Desmosomes

Strong attachments in epithelial and muscle cells.

Cytoskeletal Intermediate Filaments

Reinforce desmosomes within cells.

Selective Adhesion

Cells bind only to similar tissue type cells.

Cadherins

Linking proteins in desmosomes for cell adhesion.

Antibodies

Proteins binding specifically to other proteins.

Gap Junctions

Channels connecting adjacent animal cells for communication.

Plasmodesmata

Membrane-lined channels connecting plant cells.

Symplast

Shared cytoplasm within plant tissues.

Apoplast

Extracellular space in plant tissues.

Waterproof Seals

Function of tight junctions in epithelial tissues.

Dynamic Tight Junctions

Tight junctions can change permeability based on conditions.

Cell Aggregation

Cells of the same type can reform tissues.

Adhesion Proteins

Different proteins enable selective cell attachments.

Cytoplasmic Connections

Ions and small molecules pass between adjacent cells.

Regulatory Ions

Small molecules facilitating cellular communication.

Cellular Coordination

Gap junctions help synchronize cell functions.

Intracellular Anchoring Proteins

Proteins anchoring cytoskeletal filaments to desmosomes.

Chemical Treatment Experiment

Wilson's experiment on sponge cell adhesion.

Functional Adult Sponges

Reformed from dissociated sponge cells.

Cellular Environment Response

Tight junctions can open/close based on stimuli.

Cellular Communication Portals

Gap junctions facilitate rapid intercellular signaling.

Cell communication

Interaction between cells without physical contact.

Signaling molecules

Molecules that transmit information between cells.

Neurotransmitters

Chemical messengers that influence distant cell activity.

Hormones

Information-carrying molecules secreted into circulation.

Target cells

Cells that respond to specific signaling molecules.

Signal reception

Process of binding signaling molecules to receptors.

Receptor molecules

Proteins that change shape upon binding signals.

Lipid-soluble signals

Molecules that diffuse across plasma membranes.

Cytoplasm receptors

Receptors located within target cell's cytoplasm.

Lipid-insoluble signals

Molecules that cannot cross plasma membranes.

Cell surface receptors

Receptors located on the plasma membrane.

Dynamic receptors

Receptors whose number and sensitivity can change.

Beta-blockers

Drugs that block hormone-receptor interactions.

Steroid hormones

Lipid-soluble hormones like estrogen and cortisol.

Hormone-receptor complex

Complex that triggers gene expression changes.

Signal transduction

Conversion of extracellular signals to intracellular responses.

Second messengers

Small molecules that amplify intracellular signals.

G-protein-coupled receptors

Receptors that initiate second messenger production.

Enzyme-linked receptors

Transmembrane proteins catalyzing reactions and phosphorylate proteins inside cells.

G proteins

Peripheral proteins activated by signaling receptors.

GDP and GTP

Nucleotides exchanged during G protein activation.

Signal amplification

Process of increasing signal strength within cells.

Intracellular signals

Signals generated inside cells from external stimuli.

Gene expression changes

Alterations in protein production due to signals.

Signal diversity

Variety of responses generated from a single signal.

Plasma membrane

Barrier that separates cell interior from environment.

G protein subunit

Activates nearby enzyme for signaling.

Second messenger

Small molecules amplifying hormone signals.

Protein kinases

Enzymes adding phosphate groups to proteins.

Calcium ion (Ca2+)

Activates proteins via calmodulin complex.

Cyclic AMP (cAMP)

Activates specific protein kinases.

Cyclic GMP (cGMP)

Opens ion channels and activates kinases.

Diacylglycerol (DAG)

Activates certain protein kinases.

Inositol trisphosphate (IP3)

Opens calcium channels for cytosol entry.

Receptor tyrosine kinases (RTKs)

Best-known group of enzyme-linked receptors.

Phosphorylation cascade

Series of protein phosphorylations amplifying signals.

Mitogen-activated protein kinases (MAPKs)

Activate cell division via phosphorylation.

Signal response

Change in gene expression or protein activity.

Abscisic acid

Hormone regulating plant response to drought.

Signal deactivation

Mechanisms to turn off intracellular signals.

Phosphatases

Remove phosphate groups in signaling pathways.

Crosstalk

Integration of multiple signaling pathways.

Quorum sensing

Bacterial communication based on population density.

Biofilm

Community of microbes adhering together.

Threshold response

Signal response varies with population density.

Slime mold aggregation

Free-living cells aggregate via signaling.