Cellular Transport and Membrane Dynamics

Flashcards covering cellular transport mechanisms, membrane proteins, and the effects of solute concentrations on cell state based on the lecture transcript.

Diffusion (Simple Diffusion)

A passive transport process involving the movement of molecules from an area of high concentration to an area of low concentration where no energy is required.

Osmosis

The diffusion of water across a selectively permeable membrane, moving from a high concentration of water to a low concentration.

Selective Permeability

A characteristic of a membrane that allows some substances to pass through while blocking others, acting as a gatekeeper for the cell.

Osmotic Pressure

Pressure that develops when water moves across a selectively permeable membrane; it is essential for maintaining cell volume, turgor in plant cells, and overall water balance.

Turgor Pressure

Hydrostatic pressure or force exerted by the fluid within a cell against its cell wall, primarily due to the osmotic flow of water into the plant cell.

Cause of Selective Permeability

The combination of the hydrophobic phospholipid interior blocking many molecules and specific transport proteins acting as gates or carriers.

Plasmolysis

The shrinking of a plant cell’s cytoplasm away from its cell wall due to water loss in a hypertonic solution, leading to wilting.

Cytolysis

The swelling of the cell, which could cause the cell to explode.

Hypertonic

A solution that has a higher concentration of solutes than another solution, which causes a cell to shrink.

Hypotonic

A solution that has a lower concentration of solutes than another solution, which causes a cell to swell.

Isotonic

A solution where the concentration of solutes is equal inside and outside the cell, resulting in no change to the cell shape.

Phagocytosis

A type of endocytosis where a cell engulfs and digests a solid particle or food, such as white blood cells eating bacteria.

Pinocytosis

A type of endocytosis where a cell takes in fluid containing nutrients by engulfing fluid particles into a vacuole.

Endocytosis

An active transport process where cells take in material by moving toward the inside through vesicle formation.

Exocytosis

An active transport process requiring energy where the cell expels materials like hormones or enzymes as a vesicle fuses with the plasma protein.

Receptor-Mediated Endocytosis

A type of active transport where substances like cholesterol are absorbed into cells only after gaining permission through bonding with specific receptors.

Solute

The substance being dissolved in a solution.

Solvent

The substance doing the dissolving in a solution.

Concentration

The amount of solute dissolved in a given amount of solvent or solution.

Facilitated Diffusion

A type of passive transport that involves diffusion with the help of transport proteins (channels or carrier proteins) across the membrane toward lower concentration.

Active Transport

A process where the cell uses energy and carrier proteins to move substances toward higher concentrations, such as sugars, amino acids, and ions.

Passive Transport

A process where the cell does not use energy to move substances toward lower concentrations, including simple diffusion, facilitated diffusion, and osmosis.

Crention

A term describing a red blood cell going through plasmolysis.

Carrier Proteins

Proteins that combine with a substance and help move it across the membrane; they are necessary for processes like nerve conduction.

Channel Proteins

Proteins that have a channel allowing a substance to simply move across a membrane.

Cell Recognition Proteins

Proteins that help the body recognize invasion by pathogens so an immune response can occur.

Receptor Proteins

Proteins with a specific shape that allows a molecule to bond, causing the protein to change shape and trigger a cellular response.

Enzymatic Proteins

Plasma membrane proteins that directly carry out metabolic reactions.