Biology2

Plasma Membrane

Separates internal cytoplasm from external environment.

Phospholipid Bilayer

Lipid component with hydrophilic heads and hydrophobic tails.

Fluid Mosaic Model

Describes membrane structure with proteins and lipids.

Integral Proteins

Proteins embedded in the membrane, can be transmembrane.

Peripheral Proteins

Proteins located on the inner membrane surface.

Cholesterol

Regulates fluidity of the plasma membrane.

Glycoproteins

Proteins with carbohydrate chains for cell recognition.

Glycolipids

Lipids with carbohydrate chains, important for identification.

Major Histocompatibility Complex (MHC)

Unique glycoproteins for individual immune response.

Receptor Proteins

Bind specific molecules, facilitating cellular responses.

Enzymatic Proteins

Catalyze specific biochemical reactions in the membrane.

Selective Permeability

Allows certain substances to cross the membrane.

Diffusion

Movement of molecules from high to low concentration.

Facilitated Transport

Movement via channels or carriers down a gradient.

Active Transport

Movement against concentration gradient using energy.

Bulk Transport

Transport of large particles via vesicles.

Exocytosis

Vesicle fusion with membrane to release contents.

Endocytosis

Vesicle formation to bring substances into the cell.

Osmosis

Diffusion of water across a selectively permeable membrane.

Osmotic Pressure

Pressure developed due to water movement in osmosis.

Isotonic Solution

Equal solute and water concentrations on both sides.

Hypotonic Solution

Lower solute concentration outside, causing cell swelling.

Hypertonic Solution

Higher solute concentration outside, causing cell shrinkage.

Crenation

Shrinking of animal cells in hypertonic solutions.

Plasmolysis

Shrinking of plant cells in hypertonic solutions.

Aquaporins

Specialized proteins facilitating water transport.

Concentration Gradient

Difference in concentration of a substance across a space.

Equilibrium

State where net movement of molecules stops.

Carrier Proteins

Assist in transporting molecules across the membrane.

Turgor Pressure

Pressure exerted by fluid in plant cells.

Lysis

Rupture of animal cells due to excess water.

Isotonic

Equal concentration of solutes in blood and environment.

Contractile Vacuoles

Organelles that expel excess water in protozoans.

Sodium-Potassium Pump

Transports sodium out and potassium into cells.

ATP

Energy currency used in active transport.

Phagocytosis

Endocytosis of large solid materials.

Pinocytosis

Endocytosis of liquids or small particles.

Receptor-Mediated Endocytosis

Specific endocytosis using receptor proteins.

Extracellular Matrix (ECM)

Network of proteins and polysaccharides outside cells.

Collagen

Protein that resists stretching in ECM.

Elastin

Protein providing resilience to the ECM.

Fibronectin

Adhesive protein binding to integrin.

Integrin

Protein involved in cell signaling.

Proteoglycans

Molecules that resist compression in ECM.

Adhesion Junctions

Intercellular filaments connecting adjacent cells.

Desmosomes

Internal plaques providing structural support.

Tight Junctions

Form impermeable barriers between cells.

Gap Junctions

Channels allowing communication between cells.

Plasmodesmata

Channels for material passage in plant cell walls.

Cell Wall

Rigid structure providing support in plant cells.

Fluid-Mosaic Model

Describes plasma membrane structure and function.

Channel Protein

Allows specific molecules to cross membranes.

Carrier Protein

Transports specific molecules across membranes.

Cell Recognition Protein

Identifies cells for immune response.

Receptor Protein

Binds specific molecules to initiate response.

Enzymatic Protein

Catalyzes specific reactions in membranes.

Junction Proteins

Connect cells for tissue function.

Signal Transduction

Process of transmitting signals within cells.

Transduction pathway

Relay proteins activate a target protein.

Signaling molecules

Activate receptor proteins on cell membrane.

Targeted proteins

Proteins that elicit cellular responses.

Structural protein

Changes cell shape or movement.

Enzyme

Modifies metabolism or cellular function.

Gene regulatory protein

Influences gene expression and protein production.

Oxygen diffusion

Oxygen moves from alveoli to capillaries.

Equilibrium in diffusion

Equal distribution of molecules in a space.

Isotonic solution

No net water movement occurs.

Hypotonic solution

Water enters cell, may cause lysis.

Hypertonic solution

Water leaves cell, causing crenation.

Turgor pressure

Pressure from water in plant vacuoles.

Carrier protein

Facilitates solute transport across membranes.

Receptor-mediated endocytosis

Specific uptake of solutes via receptors.

Adhesion junction

Connects cells with cytoskeletal filaments.

Tight junction

Prevents leakage between adjacent cells.

Gap junction

Allows communication between adjacent cells.

Selectively permeable membrane

Allows specific substances to pass through.

Cellular response

Outcome of target protein activation.

Extracellular matrix

Network providing structural support to cells.