Gaseous Exchange - Introduction (Life Sciences Grade 11 CAPS) - Vocabulary flashcards

Vocabulary flashcards covering key terms related to gaseous exchange, its requirements, adaptations across plants and animals, and related structures.

Gas exchange

The process by which oxygen enters an organism and carbon dioxide leaves, enabling cellular respiration; relies on a moist, thin gas exchange surface and a transport system.

Oxygen

A gas required for cellular respiration to release energy from glucose.

Cellular respiration

The process by which cells break down glucose to release energy, using oxygen and producing carbon dioxide as a by‑product.

Carbon dioxide

A gas produced during cellular respiration; must be removed to prevent formation of carbonic acid and pH changes.

Carbonic acid

The acid formed when carbon dioxide dissolves in water (H2CO3).

pH

A measure of how acidic or basic (alkaline) a solution is; changes in pH can affect enzyme activity.

Enzymes

Biological catalysts whose activity is sensitive to pH; extreme pH can denature them.

Gas exchange surface

A large, moist, thin surface where gases diffuse between an organism and its environment.

Surface area to volume ratio

The ratio of surface area to volume; as an organism grows, volume increases faster than surface area, reducing the ratio and affecting gas exchange efficiency.

Alveoli

Tiny air sacs in the lungs where gas exchange with the blood occurs; greatly increase surface area.

Lungs

The organs where mammalian gas exchange occurs via alveoli and capillaries.

Stomata

Pores on plant leaves that allow gas exchange; regulate entry of CO2 and exit of O2 and water vapor.

Lenticels

Openings in woody stems that facilitate gas exchange between internal tissues and the atmosphere.

Spiracles

External respiratory openings on the bodies of insects.

Tracheal tubes

A network of tubes in insects that transport air directly to tissues for gas exchange.

Gills

Respiratory organs of fish consisting of filaments with a dense capillary network for diffusion of gases.

Spongy mesophyll cells

Leaf mesophyll cells with many air spaces that aid gas exchange in leaves.

Mesophyll

Leaf tissue containing mesophyll cells; involved in photosynthesis and gas exchange; includes palisade and spongy layers.

Squamous epithelium

Thin, flattened tissue making up sites like the alveolar walls to facilitate rapid diffusion.

Coelomic fluid

Fluid in earthworms that helps keep the skin moist for diffusion-based gas exchange.

Ventilation

Movement of air or water to or from gas exchange surfaces; coordinated by muscles such as the diaphragm and intercostals in animals.

Diaphragm

A dome-shaped muscle that, with intercostal muscles, aids breathing by changing thoracic volume.

Intercostal muscles

Muscles between the ribs that assist with ventilation by expanding and contracting the chest cavity.

Rib cage

Protective framework around the lungs consisting of ribs, sternum, vertebral column and intercostal muscles.

Intercellular air spaces

Air-filled spaces within leaf tissue (mesophyll) that facilitate gas diffusion.

Moisture (gas exchange surfaces must be moist)

Gas exchange surfaces must remain moist to permit efficient diffusion of gases.

Spiracle flap

Protective flaps that cover spiracles in insects, helping protect the gas exchange openings.

Photosynthesis

The process by which green plants use light energy to convert carbon dioxide and water into glucose and oxygen.