Diffusion, Osmosis and Active Transport Flashcards
What is the definition of diffusion?
The random net movement of particles from an area of high concentration to an area of low concentration until equilibrium.
What is active transport?
Active transport is the movement of particles from a low concentration to a high concentration through energy.
What is osmosis?
It is the movement of water from a high water potential to a low water potential through a partially permeable membrane.
Why is diffusion important in cells?
Because oxygen is needed to diffuse into cells and carbon dioxide needs to diffuse out of cells to keep them working. This is part of the respiratory system.
What affects the rate of diffusion?
- The temperature. The higher the temperature, the more energy particles will have and therefore diffusion will happen quicker.
- The concentration of particles. The higher the concentration of particles, the quicker diffusion will happen.
- The volume of the container/ the surface area of the membrane that particles are crossing.
How is osmosis different from diffusion?
Because osmosis only applies to water, and doesn’t allow all particles to spread out, whereas diffusion is just about everything being evenly distributed.
Why is osmosis important in animal cells?
It regulates water going in and out of cells, helping cells to maintain their shape and size. It is also important for the transfer of nutrients
Why is osmosis important in plant cells?
Osmosis is used in the roots to transport water from the soil into the plant. It is also used with the movement of stomata.
Why is active transport important in cells?
Because it gets all of the nutrients that is needed from the soil into the root hair cells for plants (as the plant has lots of nutrients and the soil doesn’t)
It also helps with absorption of small amounts of sugar into the villi in the human body.
What is the effect of osmosis on plant cells if the plant has too much water or too much sugar/salt?
The effect is that the cell with either go turgid or flaccid.
If it goes flaccid then the cell has too little water/ too much sugar/salt and it shrivels and dries.
If it goes turgid then the cell has too much water, and fills, expands, and then bursts.
How do you investigate the effect of osmosis on plant tissues?
You can do this by getting 3 pieces of potato (preferably of equal weights), and following the steps below:
1. Dry them
2. Weigh them.
3. Place each of them in a different concentration of salt to water: put one in high concentration, one in low concentration, and one in same concentration.
4. Leave them in for a few minutes in the water.
5. Remove them and dry them again
6. Weigh them again - are they different weights?
