T1- Diffusion, osmosis and active transport Flashcards
What is diffusion?
Diffusion is the spreading out of particles from an area of higher concentration to an area of lower concentration.
It happens in liquids and gases as the particles in these substances are free to move about randomly.
What does partially permeable mean?
Cell membranes are partially permeable as only some molecules can pass through the membrane.
Which molecules are able to diffuse into and out of cells?
Glucose, water, amino acids and oxygen.
Which molecules aren’t able to diffuse into and out of cells?
Starch and proteins.
What 3 factors affect the rate of diffusion?
Temperature - The higher the temperature, the faster the diffusion rate because the particles have more energy so move around faster.
Concentration gradient - The bigger the concentration gradient (the difference in concentration), the faster the diffusion rate.
Surface area - The larger the surface area, the faster the diffusion rate because more particles can get through at once.
What is osmosis?
Osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of a lower water concentration.
What is active transport?
Active transport is the movement of molecules across a membrane, from a region of low concentration to a region of high concentration. This requires energy from respiration.
Is active transport a passive or active process?
Active
Where do plants absorb mineral ions from?
Soil
Why can’t plants absorb mineral ions by diffusion?
Their concentration is higher in the cell than in the soil.
Which cells in the plant are adapted to absorb mineral ions?
Root hair cell
