Quizlet BIOL 5

Phospholipids Main component of cell membranes, amphipathic molecules.

Hydrophilic Head Polar part of phospholipid, attracts water.

Hydrophobic Tails Nonpolar part of phospholipid, repels water.

Saturated Fatty Acids Fatty acids with only single C-C bonds.

Unsaturated Fatty Acids Fatty acids with at least one double C=C bond.

Phospholipid Bilayer Two layers of phospholipids with tails inward.

Fluid Mosaic Model Membrane structure with diverse components, proposed in 1972.

Integral Proteins Proteins fully embedded in the phospholipid bilayer.

Transmembrane Proteins Integral proteins that span the entire membrane.

Peripheral Proteins Proteins located on the membrane's surface.

Carbohydrates Components for cell recognition, attached to proteins/lipids.

Glycoproteins Carbohydrates bonded to proteins on the membrane.

Glycolipids Carbohydrates bonded to lipids on the membrane.

Membrane Fluidity Flexibility of the membrane, influenced by various factors.

Cholesterol Regulates membrane fluidity across temperature changes.

Temperature Effects Cold makes membranes rigid; heat increases fluidity.

Asymmetry of Membrane Inner and outer surfaces of membranes differ.

Cell Signaling Membranes receive signals and initiate cellular responses.

Cell Adhesion Membranes help cells stick to each other.

Transporters Proteins that facilitate movement of substances across membranes.

Receptors Proteins that bind to external signals.

Enzymes Proteins that catalyze biochemical reactions in membranes.

Binding and Adhesion Proteins Facilitate attachment between cells.

Phosphate Group Polar component of phospholipids, part of hydrophilic head.

Fatty Acid Chains Hydrophobic tails in phospholipids, can be saturated/unsaturated.

Membrane Functions Define cell borders, manage transport, and signal reception.

Fluid Mosaic Model Describes cell membrane structure and function.

Phospholipid Function Forms bilayer, providing barrier and fluidity.

Protein Function Facilitates transport and communication across membranes.

Carbohydrate Function Involved in cell recognition and signaling.

Passive Transport Movement across membrane without energy input.

Osmosis Diffusion of water across a semipermeable membrane.

Diffusion Movement from high to low concentration.

Tonicity Relative concentration of solutes in solutions.

Selectively Permeable Allows specific molecules to pass through membrane.

Permeant Molecules Molecules that can cross the phospholipid bilayer.

Concentration Gradient Difference in concentration across a space.

Equilibrium State where concentrations are equal on both sides.

Facilitated Diffusion Transport of substances via membrane proteins.

Channel Proteins Transmembrane proteins that allow specific ions through.

Carrier Proteins Bind and transport specific substances across membranes.

Hydrophobic Molecules Nonpolar molecules that easily pass through membranes.

Small Polar Molecules Can pass through membranes, e.g., water.

Large Polar Molecules Cannot pass through membranes, e.g., glucose.

Ions Charged molecules that cannot cross membranes freely.

Factors Affecting Diffusion Concentration, mass, temperature, surface area, pressure.

Gated Channel Proteins Open in response to specific signals.

Nonpolar Molecules Easily diffuse through the lipid bilayer.

High Temperature Effect Increases molecular movement and diffusion rates.

Surface Area Effect Larger area increases diffusion speed.

Blood Pressure Role Forces solutions through membranes, enhancing diffusion.

Osmosis Diffusion of water across a selectively permeable membrane.

Concentration Gradient Difference in solute concentration across a membrane.

GLUTS Glucose transport proteins facilitating glucose movement.

Tonicity Relative concentration of solute and water across membranes.

Hypertonic Solution Higher solute concentration than cytosol; water exits cell.

Isotonic Solution Equal solute concentration to cytosol; no net water movement.

Hypotonic Solution Lower solute concentration than cytosol; water enters cell.

Turgor Pressure Pressure from plasma membrane against cell wall in plants.

Plasmolysis Detachment of plasma membrane from cell wall in hypertonic solutions.

In Vivo Experiments conducted in a living organism.

In Vitro Experiments conducted in a controlled environment, like a test tube.

Contractile Vacuoles Organelles in freshwater protists that expel excess water.

Osmoregulation Regulation of water balance in organisms.

Extracellular Fluid Fluid outside cells affecting their volume and tonicity.

Cytosol Liquid component of the cytoplasm within cells.

Water Concentration Amount of water relative to solute in a solution.

Selectively Permeable Membrane Membrane allowing certain substances to pass, blocking others.

Animal Cells Function best in isotonic extracellular environments.

Solute Substance dissolved in a solution, affecting water movement.

Diffusion Movement of particles from high to low concentration.

Membrane Permeability Ability of a membrane to allow substances to pass.

Osmotic Pressure Pressure required to prevent water movement across a membrane.

Cell Wall Rigid outer layer in plant cells providing structure.

Wilting Loss of turgor pressure in plants due to water loss.

Marine Invertebrates Organisms matching internal salt concentration to their environment.

Diluted Urine Excretion Fishes excrete to eliminate excess H2O or salts.

Passive Transport Movement across membranes without energy input.

Diffusion Movement of molecules from high to low concentration.

Active Transport Movement against concentration gradient requiring energy.

Electrochemical Gradient Combined effects of concentration and electrical gradients.

Primary Active Transport Uses ATP to move substances against gradients.

Secondary Active Transport Uses existing gradients to move different substances.

Uniporter Transports one molecule or ion across membrane.

Symporter Transports two molecules in the same direction.

Antiporter Transports two molecules in opposite directions.

Na+-K+ Pump Moves 3 Na+ out and 2 K+ in using ATP.

Electrogenic Pump Creates a charge difference across the membrane.

Endocytosis Process of importing substances into the cell.

Exocytosis Process of exporting substances from the cell.

Phagocytosis Cellular eating; engulfs large particles.

Pinocytosis Cellular drinking; engulfs small volumes of fluid.

Receptor-Mediated Endocytosis Targets specific substances via membrane receptors.

Vesicles Membrane-bound sacs transporting substances in cells.

Carrier Proteins Integral proteins facilitating active transport.

Hydrolysis of ATP Releases energy for active transport processes.

Membrane Proteins Proteins that assist in transport across membranes.

Cell Membrane Barrier controlling entry and exit of substances.

Cytoplasm Fluid inside the cell where organelles reside.

Anions Negatively charged ions present in the cytoplasm.

Molecules Smallest units of chemical compounds.

Transport Proteins Proteins that facilitate movement of substances.