Chapter 1-7 Notes Review: Diffusion, Osmosis, and Cellular Transport

A set of QA flashcards covering diffusion, osmosis, tonicity, filtration, and various types of active and vesicular transport as described in chapters 1-7 notes.

What is diffusion and in which direction does it typically move?

Diffusion is the random movement of molecules that proceeds from high concentration to low concentration until equilibrium is reached.

What does impermeable mean in diffusion contexts?

Im permeable means a membrane cannot be crossed by a substance, so the substance cannot pass through.

What is osmosis?

Osmosis is the movement of water across a membrane (not the solvent) driven by a concentration gradient.

What does passive transport mean?

Passive transport is the movement of substances across membranes without the use of cellular energy.

In osmosis, what happens when free water concentrations are equal on both sides?

There is equilibrium; water movement net is zero and the system stays balanced.

What does isotonic mean for a cell?

An isotonic solution has equal water movement in and out, so the cell remains the same size.

What is a hypertonic solution and its effect on cells?

A hypertonic solution has higher external solute concentration; water leaves the cell and the cell shrinks.

What is a hypotonic solution and its effect on cells?

A hypotonic solution has lower external solute concentration; water enters the cell and the cell swells, potentially lysing.

What is crenation (cremation) in red blood cells?

Crenation is the shrinkage of red blood cells in hypertonic solutions, giving a scalloped edge.

What happens to red blood cells in a hypotonic solution?

Water moves into the cell; the cell swells and may burst (hemolysis) if the influx is large.

What is hemolysis?

Hemolysis is the rupture or lysis of red blood cells due to osmotic imbalance in a hypotonic environment.

What is filtration in physiology?

Filtration is the movement of substances across a membrane driven by a pressure difference (from high to low pressure).

What is primary active transport?

Primary active transport uses direct energy (usually ATP) to move substances against their gradient.

What is secondary active transport?

Secondary active transport uses the gradient of one molecule to drive the transport of another; can be symport or antiport.

What is a symport transporter?

A transporter that moves two or more substances in the same direction across a membrane.

What is an antiport transporter?

A transporter that moves substances in opposite directions across a membrane.

What is exocytosis?

Exocytosis is the process of moving substances out of a cell via vesicle fusion with the plasma membrane.

What is endocytosis?

Endocytosis is the process of bringing substances into a cell via membrane invagination; includes phagocytosis and pinocytosis.

What is receptor-mediated endocytosis?

A selective form of endocytosis where receptors on the membrane recognize specific substances for uptake (often involving fats in liver, muscle, and adipose tissue).