Exchange substances official content key terms

Exchange surfaces

Specialized structures that facilitate the transfer of substances between an organism and its environment, such as lungs or gills.

Adaptations

Features that enhance an organism's ability to exchange substances, such as increased surface area or thin membranes.

Surface Area

The total area of the surface of a three-dimensional object, crucial for exchange processes.

Volume

The amount of space an object occupies, which increases more rapidly than surface area as size increases.

Surface area to volume ratio

The relationship between the surface area of an object and its volume, which affects the rate of exchange of substances.

Countercurrent exchange

A mechanism where two fluids flow in opposite directions, enhancing the efficiency of gas or heat exchange.

Mass transport system

A system that facilitates the movement of substances throughout an organism, such as the circulatory system in animals or the vascular system in plants.

Surface area to volume ratio

A measure of the amount of surface area per unit volume of an object, which affects the rate of diffusion and heat exchange.

Gas exchange

The process of obtaining oxygen from the environment and releasing carbon dioxide.

Diffusion

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

Diffusion

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

Concentration gradient

A difference in the concentration of a substance across a space, which drives diffusion.

Stomata

Small openings on the leaf surface that facilitate gas exchange and transpiration.

Guard cells

Specialized cells that control the opening and closing of stomata.

Ventilation

The process of moving air in and out of the lungs to facilitate gas exchange.

Alveoli

Tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs.

Diffusion

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

Ventilation

The process of moving air in and out of the lungs to facilitate gas exchange.

Emulsification

The process of breaking down large fat globules into smaller droplets to increase the surface area for enzyme action.

Chylomicrons

Lipid transport particles formed in the intestinal cells, consisting of triglycerides, cholesterol, and proteins.

Hydrolysis

A chemical process that splits molecules by the addition of water, often catalyzed by enzymes.

Enzyme

A biological catalyst that accelerates chemical reactions in living organisms.

Villi

Finger-like projections in the ileum that increase surface area for absorption.

Microvilli

Tiny projections on the surface of epithelial cells that further increase surface area and enhance absorption.

Intestinal Epithelium

The layer of cells lining the intestine, responsible for nutrient absorption and barrier functions.

Concentration Gradient

A difference in the concentration of a substance across a space, which drives the movement of substances during diffusion or active transport.

Hemoglobin

A globular protein in red blood cells that binds oxygen for transport from the lungs to tissues.

Oxygen dissociation curve

A graph that shows the relationship between the partial pressure of oxygen and the saturation of hemoglobin with oxygen.

Oxygen dissociation curve

A graph that shows the relationship between the partial pressure of oxygen and the saturation of hemoglobin with oxygen.

Bohr effect

The phenomenon where increased carbon dioxide concentration and lower pH reduce hemoglobin's affinity for oxygen, promoting oxygen release.