Osmosis and Diffusion Flashcards
(20 cards)
What is diffusion?
Diffusion is the movement of particles from an area of high concentration to low concentration until equilibrium is reached.
What is osmosis?
Osmosis is the movement of water molecules from an area of high water concentration to low water concentration across a semi-permeable membrane.
Does osmosis require energy?
No, osmosis is a passive process (does not require energy).
Does diffusion require a semi-permeable membrane?
No, diffusion can occur with or without a membrane.
Name one example of diffusion in plants.
Carbon dioxide diffusing into a leaf for photosynthesis.
Name one example of diffusion in animals.
Oxygen diffusing from the lungs into the bloodstream.
What happens to a red blood cell in pure water?
Water enters the cell by osmosis, causing it to swell and possibly burst (lysis).
What happens to a red blood cell in a salt solution?
Water leaves the cell by osmosis, causing it to shrink and shrivel (crenation).
What happens to a plant cell in pure water?
Water enters by osmosis, making it turgid (firm and swollen).
What happens to a plant cell in salt water?
Water leaves by osmosis, causing plasmolysis (the cell membrane shrinks away from the cell wall).
What is turgor pressure?
The pressure of water inside a plant cell pushing against the cell wall, keeping the plant firm.
How do the kidneys use osmosis?
The kidneys reabsorb water from urine to maintain water balance in the body.
List three factors that affect the rate of diffusion.
- Temperature (higher = faster), 2. Concentration gradient (steeper = faster), 3. Surface area (larger = faster).
Why does diffusion happen faster at higher temperatures?
Heat gives particles more energy, causing them to move faster and spread out quicker.
What is plasmolysis?
Plasmolysis is when a plant cell loses water and the cell membrane pulls away from the cell wall, causing the cell to shrink.
Why do hospital IV fluids need to have the same salt concentration as blood?
To prevent red blood cells from swelling or shrinking due to osmosis.
What is the difference between osmosis and active transport?
Osmosis is passive and moves water from high to low concentration, while active transport requires energy (ATP) and moves substances from low to high concentration.
What is the function of a semi-permeable membrane in osmosis?
It allows water molecules to pass through but blocks larger molecules.
What happens to the mass of a potato slice placed in pure water?
The mass increases because water enters by osmosis.
What happens to the mass of a potato slice placed in salt water?
The mass decreases because water leaves by osmosis.
