Biology Lecture on Membrane Fluidity and Transport

These flashcards cover key vocabulary terms related to membrane structure, fluidity, transport mechanisms, and associated biological concepts.

Cholesterol

A substance that buffers the fluidity of cell membranes, maintaining optimal levels.

Hydrogen Bonding

The interaction between partially positive hydrogen and partially negative oxygen or nitrogen atoms.

Saturated Fatty Acids

Fatty acids without double bonds that create a straight hydrocarbon chain.

Hydrophobic

Molecules or regions that repel water and do not interact favorably with it.

Hydrophilic

Molecules or regions that are attracted to water and can interact favorably with it.

Observation

Data collected from experiments or situations that must be analyzed to support or refute a hypothesis.

Hypothesis

A proposed explanation for a phenomenon, which can be tested through observations and experiments.

Fluidity of Membrane

The property of cell membranes that allows for movement and flexibility based on temperature and composition.

Double Bond

A chemical bond involving two pairs of electrons that creates kinks in fatty acid tails, affecting membrane fluidity.

Cell Membrane

A barrier that separates the interior of cells from the external environment, composed of a lipid bilayer.

Diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration.

Osmosis

The movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water, compared to the cell's internal environment.

Isotonic

A solution that has the same solute concentration as another solution, resulting in no net movement of water.

Hypertonic

A solution with a higher solute concentration than inside the cell, causing the cell to lose water.

Hypotonic

A solution with a lower solute concentration than inside the cell, causing the cell to gain water.

Selectively Permeable

A characteristic of membranes that allows certain molecules to pass while blocking others.

Active Transport

The movement of molecules against their concentration gradient, requiring energy.

Passive Transport

The movement of molecules across a membrane without the use of energy, including diffusion and osmosis.

Electrolytes

Minerals in the body that have an electric charge, crucial for various bodily functions.

Permeability

The ability of a membrane to allow substances to pass through.

Lipid Bilayer

The double-layered structure that forms the core of all cell membranes.

Pinocytosis

A form of endocytosis in which the cell ingests extracellular fluid and dissolved solutes.

Endocytosis

The process by which cells take in substances by engulfing them.

Exocytosis

The process by which a cell expels materials in vesicles.

Cohesion

The attraction between molecules of the same substance, important in water transport.

Adhesion

The attraction between different substances, such as water and plant cell walls.

Hydrophilic Head

The part of a phospholipid molecule that interacts favorably with water.

Hydrophobic Tail

The part of a phospholipid molecule that repels water.

Signal Transduction

The process by which a cell responds to signals from the environment through receptors.

Facilitated Diffusion

The process of spontaneous passive transport of molecules across a membrane via specific transmembrane proteins.

Concentration Gradient

The difference in the concentration of a substance across a space.

Biological Membranes

Structures that separate and protect the internal environment of cells from the external environment.

Fluid Mosaic Model

A model that describes the structure of cell membranes as a mosaic of diverse protein molecules embedded in a fluid phospholipid bilayer.

Steady State

The balance between processes facilitating and opposing a change.

Kinetic Energy

The energy an object has due to its motion, important in diffusion processes.

Integral Proteins

Proteins that span the entire membrane and are involved in the transport of molecules.

Peripheral Proteins

Proteins that are attached to the surface of the membrane and can be removed easily.

Aquaporins

Water channel proteins that facilitate the flow of water across cell membranes.

Phospholipids

Molecules that make up the bilayer of cell membranes, consisting of a hydrophilic head and two hydrophobic tails.

Membrane Potential

The voltage difference across a membrane, which is crucial for the functioning of neurons.

Glycolipids

Lipids with a carbohydrate attached; they play a role in cell recognition.

Glycoproteins

Proteins with carbohydrate groups attached that are involved in cell recognition and signaling.

Homeostasis

The maintenance of stable internal conditions within an organism.

Transport Proteins

Proteins that assist in the movement of substances across a cell membrane.

Chemiosmosis

The process by which ATP is produced using energy stored in a proton gradient across a membrane.