Cell-Cell Interactions and Signaling in Multicellular Organisms

Cell-Cell Interactions

Communication and cooperation between multicellular organism cells.

Extracellular Matrix (ECM)

Fiber composite secreted by animal cells for support.

Collagen

Cable-like protein forming flexible ECM structure.

Proteoglycans

Proteins attached to polysaccharides in ECM.

Ground Substance

Gel-like component of ECM attracting water.

Integrins

Membrane proteins connecting ECM to cytoskeleton.

Laminins

Glycoproteins binding ECM to integrin proteins.

Turgor Pressure

Pressure from fluid in plant cells maintaining shape.

Primary Cell Wall

First layer secreted by plant cells for structure.

Cellulose Microfibrils

Cable-like structures forming plant cell walls.

Expansins

Proteins allowing plant cell growth by disrupting microfibrils.

Secondary Cell Wall

Stronger wall secreted by mature plant cells.

Middle Lamella

Layer gluing adjacent plant cells together.

Tight Junctions

Membrane proteins creating watertight seals between animal cells.

Desmosomes

Proteins linking cytoskeletons of adjacent animal cells.

Gap Junctions

Channels allowing small molecule flow between animal cells.

Plasmodesmata

Cytoplasmic threads connecting adjacent plant cells.

Hormones

Signaling molecules secreted to communicate with distant cells.

Neurotransmitters

Molecules transmitting signals between nerve cells.

Signal Receptors

Proteins changing shape upon hormone binding.

Signal Transduction

Process converting extracellular signals to intracellular responses.

Lipid-Soluble Hormones

Hormones able to cross plasma membranes easily.

Lipid-Insoluble Hormones

Hormones unable to cross plasma membranes.

Gene Expression Change

Alteration in which genes are activated in cells.

Protein Activation Change

Modification of existing protein activity in cells.

SSRIs

Selective serotonin reuptake inhibitors affecting neurotransmitter signaling.

Prozac

Example of an SSRI used for depression.

Lexapro

Another SSRI example for treating anxiety.

Cytosol

Fluid component of the cell where receptors bind.

Cell Communication

Process by which cells exchange information.

Extracellular Layer

Protective layer defining cell shape and attachment.

Connective Tissue ECM

ECM variant providing structural support in tissues.

Bone ECM

Dense ECM providing rigidity and strength.

Cartilage ECM

Flexible ECM allowing movement and support.

Cell Shape Definition

Determined by the primary cell wall in plants.

Dynamic Tight Junctions

Tight junctions that can open and close.