Diffusion Flashcards
(20 cards)
What is the definition of diffusion?
The spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.
How does diffusion occur?
When many particles are close together, they collide with each other more often, resulting in them moving around and becoming mixed with other particles in the area.
Is diffusion an active or passive process?
It is passive as no energy is required.
What types of molecules can move across cell membranes via diffusion?
Small molecules such as oxygen, glucose, amino acids, and water can move across, but starch and proteins cannot.
What is gas exchange in the body?
Oxygen moves through the membranes of alveoli into red blood cells, and carbon dioxide moves from red blood cells into the lungs to be exhaled.
What is the role of urea in diffusion?
Urea moves from the liver cells into the blood plasma to be transported to the kidney for excretion.
What factor affects the rate of diffusion related to concentration?
The greater the difference in concentration, the faster the rate of diffusion.
How is surface area to volume ratio calculated?
By finding the volume (length x width x height) and the surface area (length x width), and writing the ratio in the smallest whole numbers.
Why do single-celled organisms rely on diffusion?
They have a relatively large surface area to volume ratio, making diffusion sufficient to meet their metabolic needs.
How do multicellular organisms adapt for diffusion?
They have specialized surfaces and organ systems that allow for efficient transport of molecules in and out of cells.
What adaptations do lungs have for gas exchange?
Lungs have millions of alveoli covered in tiny capillaries to facilitate the transfer of oxygen and carbon dioxide.
What is the function of villi in the small intestine?
Villi increase the surface area for the absorption of digested food into the bloodstream.
How do fish gills facilitate gas exchange?
Water flows over gills where oxygen diffuses into the blood and carbon dioxide diffuses into the water.
How does temperature affect diffusion?
The greater the temperature, the greater the movement of particles, resulting in a faster rate of diffusion.
What is the effect of membrane surface area on diffusion?
The greater the surface area, the more space for particles to move through, resulting in a faster rate of diffusion.
How are plant roots adapted for water and mineral uptake?
Roots have root hair cells with large surface areas that project into the soil.
What role do stomata play in plants?
Stomata allow carbon dioxide to diffuse in for photosynthesis, while oxygen and water vapor move out.
What is the significance of having a large surface area?
The greater the surface area, the more particles can move through, resulting in a faster rate of diffusion.
Why is having a thin membrane important for diffusion?
It provides a short diffusion pathway, allowing the process to occur faster.
How does an efficient blood supply affect diffusion in animals?
It creates a steep concentration gradient, so diffusion occurs faster.
