Exchange Surfaces Flashcards
What substances can diffuse into cells?
Oxygen, glucose
What substances can diffuse out of cells?
Carbon dioxide, urea
What factors can affect the rate of diffusion?
Temperature, diffusion distance, concentration gradient
What effect does increasing temperature have on the rate of diffusion?
It increases it - molecules have more kinetic energy
What effect does reducing the diffusion distance have on the rate of diffusion?
It increases it
What effect does increasing the concentration gradient have on the rate of diffusion?
It increases it
What do root hair cells absorb from the soil?
Water and mineral ions
What processes do root hair cells use to absorb substances from the soil?
Osmosis - water absorption
Active transport - mineral ion absorption
How are root hair cells adapted to their function?
Large surface area
What is the function of villi in the small intestine?
Absorption of digested food molecules
How are villi in the small intestine adapted to their function?
Large surface area, large blood supply, one cell thick
How do the adaptations of villi in the small intestine increase the rate of absorption of digested food?
Large surface area - more absorption can occur
Thin walls (one cell thick) - short diffusion distance
Large blood supply - maintains the concentration gradient
How are the lungs adapted to aid efficient exchange of gases?
Large surface area - millions of alveoli
Short diffusion distance - alveoli are only one cell thick
Maintains the concentration gradient - large blood supply
Give a definition for osmosis
Osmosis is the diffusion of water from a high concentration to a low concentration through a partially permeable membrane
How is osmosis different to diffusion?
Osmosis is the movement of water only
