Osmosis, diffusion + active transport SPEC Flashcards
What is diffusion?
Spreading of particles of a gas/ of any substances in a solution
Net movement from area high concentration –> area of low concentration
How can the rate of diffusion be increased?
Increasing difference in concentration
How does diffusion help cells to respire?
Oxygen required for respiration passes
through cell membranes by diffusion
What is osmosis?
Diffusion of water across boundaries
Dilute (high water concentration) solution –> concentration (low water concentration) solution
Partially permeable membrane allows passage of water molecules
What causes osmosis?
Differences in the concentrations of the solutions inside and ouside cells
Similar between movement of molecules in osmosis and diffusion
Random
Requires no energy from cell
What is active transport?
Cells
Substances absorbed against concentration gradient
Partially permeable membranes
What does active transport require?
Use of energy from respiration
Importance of active transport? (in terms of ions)
Give an example
Cells able to absorb ions from dilute solutions
Root hair cells
mineral ions
dilute solutions in soil
Use of active transport in kidney tubules?
Glucose
Reabsorbed in kidney tubules
What are dissolved substances moved by?
Diffusion and active transport
What do sport drinks contain?
Sugar
water
ions
Use of sugars in sport drinks
replace sugar
energy release
during activity
use of water + ions in sport drinks
replace water + ions lost during sweating
what happens if water and ions are not replaced?
ion/water balance of body disturbed
cells dont work as efficiently
