Diffusion

What is diffusion?

Diffusion is the movement of particles from an area of high concentration to an area of low concentration.

What substances are transported by diffusion?

Oxygen and carbon dioxide during gas exchange, and urea from cells to blood are examples of substances transported by diffusion.

What affects diffusion rate?

Factors that affect diffusion rate include: 1. Concentration gradient 2. Temperature 3. Surface area of the membrane.

Why do single-celled organisms excel at diffusion?

Single-celled organisms have a large surface area to volume ratio, allowing for efficient transport of molecules.

What adaptations do multicellular organisms have for exchange?

Multicellular organisms have specialized surfaces and systems that provide a large surface area and thin membranes for effective material exchange.

Examples of exchange organs in mammals and plants?

Examples include the small intestine and lungs in mammals, and roots and leaves in plants.

Importance of surface area to volume ratio?

A higher surface area to volume ratio allows for more effective material exchange, which is essential for multicellular organisms.