Interactions Between Cells and Their Environment

These flashcards cover key vocabulary terms and definitions related to cell and molecular biology concepts, particularly focusing on the interactions between cells and their extracellular environment.

Extracellular Matrix (ECM)

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

Collagen

• most abundant protein in humans

• 25% of total protein

• characterized by a triple helix structure.

Fibronectin structure

• dimeric protein: monomers linked through disulfide bonds

Laminin structure

• timer: lined by disulfide bonds

Proteoglycans

• Protein-polysaccharide complexes that contribute to ECM structure and function.

Integrin structure

• heterodimer made of alpha and beta subunits

• structure depends on ligands

Focal Adhesions

• Localized structures where cells adhere to the ECM, involved in signal transduction and cellular responses.

Cell-ECM Adhesion

The interaction between cells and the extracellular matrix that is crucial for tissue integrity and function.

Endothelia

• line blood vessels

Epithelial Cells

• form protective layers on body surfaces and line cavities.

• skin, gut, glands, etc.

Mesenchymal Cells

• Multipotent stromal cells

• connective tissues in dermal layer

Basement Membrane

• A thin sheet of ECM that anchors epithelial cells and separates different tissue layers.

Hemidesmosomes

• anchor the epithelial cells to the basement membrane via intermediate filaments.

Cadherins

• family of proteins that mediate cell-cell adhesion

• Ca2+ dependent manner.

Selectins

• cell adhesion molecules that bind to carbohydrate moieties on glycoproteins.

Ig Superfamily

• proteins involved in cell adhesion, including immune functions.

Signal Transduction

The process by which a cell responds to substances or signals from its environment.

tissues and organs in animal cells are made of what

cells + ECM

EC

which tissue involves more cell-cell contact

epithelial tissue

which tissues involve more cell-ECM contact

connective (mesenchymal) tissue

Matrix Metalloproteinases (MMPs)

Enzymes that degrade various components of the extracellular matrix.

ECM functions

• anchorage

• migration

• barrier

• tracks cellular pathways

• transmits signals

Tight Junctions

• tight seal between adjacent epithelial cells

• prevent leakage, seal cavities

Adherens Junctions

• connect the actin filament of one cell to another.

• coordinate cell movement

• located basolateral

Desmosomes

• anchor intermediate filaments in one cell to those in another.

• located basolateral

Gap Junctions

• Channels that allow for communication and transfer of small molecules (ions) between adjacent cells.

Plasmodesmata

• Cytoplasmic channels that connect plant cells, allowing for exchange of materials.

Fibrillar Collagens type I

• provides tensile strength,

• found in tendons and ligaments.

• resist stretching an dpulling

Non-fibrillar Collagens type IV

• triple helices forms scaffold in the basement membrane.

• 1st line of defense

GAGs

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