Movement of Substances Into and Out of Cells Vocabulary Flashcards

Vocabulary flashcards covering the key terms, definitions, and transport processes in Chapter 3: Movement of Substances Into and Out of Cells.

Diffusion

The net movement of particles (such as solutes, $O_2$, or $CO_2$) from a region of higher concentration to a region of lower concentration down a concentration gradient as a result of their random movement.

Osmosis

The net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane.

Active Transport

The movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration against a concentration gradient using cellular energy (ATP) generated from respiration.

Brownian Motion

The continuous, random movement of gas or solute particles at all times, discovered by Robert Brown, which provides the kinetic energy powering passive diffusion.

Water Potential Gradient

The difference in water potential between two regions that drives the passive net movement of water molecules during osmosis.

Partially Permeable Membrane

A membrane with microscopic pores that allows smaller molecules (such as water or glucose) to pass through easily while restricting larger molecules (such as starch).

Carrier Proteins

Specific protein molecules embedded in the cell membrane that change shape using ATP from aerobic respiration to transport ions or molecules across against a concentration gradient.

Turgid

The state of a plant cell when it is firm and swollen because water has entered the vacuole by osmosis, causing the cytoplasm to press outwards against the rigid cellulose cell wall.

Turgor Pressure

The outward force exerted by water inside the vacuole and cytoplasm against the rigid, inelastic cellulose cell wall of a plant cell, providing structural support to non-woody tissues.

Plasmolysis

The process and state in a plant cell placed in a hypertonic solution where extreme water loss causes the cell membrane and cytoplasm to shrink away from the rigid cell wall.

Flaccid

The state of a plant cell when water potential equilibrium or water loss causes a drop in turgor pressure, causing the cell and plant tissue to become soft or limp.

Lysis

The swelling and bursting of an animal cell (such as a red blood cell) placed in pure water or a hypotonic solution due to net water intake by osmosis in the absence of a cell wall.

Crenation

The shrivelling and shrinking of an animal cell (such as a red blood cell) when placed in a hypertonic or concentrated solution due to net water loss by osmosis.

Microvilli

Hundreds of tiny finger-like projections formed on the free surface membrane of epithelial cells in the intestine or kidney tubules that greatly increase surface area for rapid absorption.

Root Hair Cell

A specialized plant cell with an elongated extension providing a large surface area to volume ratio for absorbing water via osmosis and mineral ions via active transport.

Decompression Sickness

A medical condition (also known as 'the bends') occurring in divers when dissolved nitrogen gas forms painful bubbles in blood vessels and joints if they ascend to the surface too quickly.

Dialysis Tubing

An artificial partially permeable membrane with specific pore sizes that allows small molecules like glucose to diffuse through while blocking larger molecules like starch.

Surface Area to Volume Ratio

A physical relationship where smaller cells or structures have a higher value, enabling a faster relative rate of diffusion and shorter penetration distance to the center.

Fick's Law

A principle stating that the rate of diffusion is inversely proportional to distance squared, meaning that an increased diffusion distance significantly slows down particle transport.

Tissue Fluid

The liquid surrounding cells in animal tissues that normally maintains an equal water potential to the liquid inside cells, preventing destructive swelling or shrivelling.