Cell Membrane Transport Quiz

The movement of molecules from a region of higher concentration to a region of lower concentration, driven by the concentration gradient.

Diffusion that occurs directly across the cell membrane without the help of any membrane proteins.

Diffusion that requires the assistance of membrane proteins, such as carrier proteins or channel proteins.

The movement of water across a semi-permeable membrane from a region of higher water concentration (lower solute concentration) to a region of lower water concentration (higher solute concentration).

The net movement of a substance across a membrane against its concentration gradient, requiring energy input.

Active transport that directly uses energy from ATP hydrolysis.

Active transport that uses the electrochemical gradient created by primary active transport to move other substances.

The process by which cells engulf large particles or fluids by forming vesicles.

The net rate of diffusion is proportional to the concentration gradient, surface area, and permeability, and inversely proportional to the thickness of the membrane.

Cell membranes are selectively permeable, meaning they allow some substances to pass through while blocking others.

The difference in concentration of a substance across a membrane, driving diffusion from higher to lower concentrations.

A special case of diffusion where the presence of a non-diffusible ion on one side of the membrane affects the distribution of diffusible ions.

Proteins and other organic anions that cannot cross the cell membrane.

Lipophilic molecules like oxygen and nitrogen that easily dissolve in the lipid bilayer and cross cell membranes.

The movement of fluid across a membrane due to a pressure difference. It is directly proportional to the pressure gradient and the filtration coefficient.

The area of the membrane multiplied by its permeability to water. It represents the ease with which fluid can pass through the membrane.

The tendency of solvent to drag along solutes as it moves across a membrane due to pressure difference.

A protein pump in the cell membrane that uses ATP to move sodium out of the cell and potassium into the cell, creating an electrochemical gradient.

A protein pump that uses ATP to pump hydrogen ions (H+) out of the cell, found in acid-secreting cells like those in the stomach.

A protein pump that uses ATP to pump calcium ions (Ca2+) out of the cytoplasm into the endoplasmic reticulum, important for muscle relaxation.

Proton pumps found in organelles like lysosomes and Golgi, responsible for pumping protons (H+) out of the cytoplasm into these compartments.

Proton pumps located in mitochondria, responsible for pumping protons from the matrix into the intermembrane space, establishing the proton gradient for ATP synthesis.

A co-transporter protein that facilitates the simultaneous movement of glucose and sodium ions into intestinal and renal cells.

A type of secondary active transport that uses the sodium gradient to move calcium out of cardiac and smooth muscle cells, contributing to muscle relaxation.

A type of endocytosis where the cell takes in large particles, such as bacteria or cellular debris.

Diffusion of weak acids and bases in their undissociated (nonionic) form. This form allows them to cross cell membranes more easily, while the ionic form struggles.

The pressure needed to prevent the movement of water across a semi-permeable membrane when there's a difference in solute concentration. It's a measure of how strongly a solution draws water.

The osmotic pressure exerted specifically by plasma proteins. These large molecules can't easily cross the membrane, creating a drawing force for water.

A solution with a higher concentration of solutes compared to plasma. A hypertonic solution can cause cells to shrink as water moves out.

A solution with a lower concentration of solutes compared to plasma. A hypotonic solution can cause cells to swell as water moves in.

Filtration across the capillary wall. It's a specialized type of filtration where even colloids like proteins are retained.

Process where cells engulf large particles like bacteria, dead tissue, or visible debris.

Specialized cells like macrophages and some white blood cells are able to perform phagocytosis.

The cell membrane surrounds the particle, forming a vacuole that fuses with lysosomes for digestion.

Process where cells take in large dissolved molecules like proteins.

The cell membrane invaginates, forming a vesicle that carries the molecules inside.

Process where cells release substances like proteins or large molecules to the outside.

Secretory granules or vesicles containing the substances fuse with the cell membrane, releasing their contents.

Exocytosis requires calcium ions (Ca2+) and energy, and special docking proteins.