Movement in and out of cells Flashcards
Remember and understand topics
Diffusion
Diffusion is the net passive movement of molecules or particles from regions of higher concentration to regions of lower concentration.
Factors affecting rate of diffusion
Concentration Gradient- Higher Gradient=diffuse faster.
Temperature-Higher temperature=diffuse faster.
Surface Area- Large surface area= diffuses faster.
Size of particles- smaller particles=diffuse faster.
Diffusion in Leaves
Carbon dioxide enters the leaf by diffusion. The stomata on the underside of the leaf allows gas exchange, and guard cells control their opening. A concentration gradient drives carbon dioxide from the air (higher concentration) into the leaf (lower concentration). The large intercellular air spaces in the spongy mesophyll provide a pathway for diffusion. The large surface area of the mesophyll cells increases gas exchange efficiency. Additionally, the thin structure of the leaf and its moist internal surfaces help in the rapid diffusion to photosynthesizing cells.
Rate of Diffusion
Rate of diffusion=surface area*concentration gradient/diffusion distance
Examples of diffusion
-A drop of food coloring spreads through a glass of water.
-The smell of perfume spreading throughout a room.
-Oxygen and carbon dioxide moving in and out of your lungs.
Surface Area: Volume Calculations
SA/V ratio=SA/V
Osmosis
The net passive movement of water/solvent molecules from an area of high concentration to low concentration through a semi-permeable membrane.
Hypotonic vs Isotonic vs Hypertonic solutions
Hypotonic- low concentration.
Isotonic- balanced concentration for both inside and outside of the cell.
Hypertonic- high concentration of solutes.
Dialysis tubing
This is a semi-permeable membrane through an experiment.
Examples of Osmosis
-Water moving from the soil into plant roots.
-Water moving from the bloodstream into cells.
-Water moving from a hypotonic solution to a hypertonic solution across a semi-permeable membrane.
What happens when animal/plant cells are immersed in different solutions?
Animal cells
-Hypotonic: Swell and burst
-Hypertonic: Shrink and shrivel
-Isotonic: Stay the same
Plant cells
-Hypotonic: Swell but don’t burst (cell wall protects them)
-Hypertonic: Shrink and plasmolyze
-Isotonic: Stay the same
Active Transport
The movement of particles through a cell membrane from a region of low concentration to high concentration using energy through respiration.
Examples of Active Transport
-The sodium-potassium pump in nerve cells.
-The uptake of glucose by cells in the small intestine.
-The uptake of mineral ions by plant roots.
