Movement of substances Flashcards
What is the meaning of concentration gradient?
It is the difference between two regions.
Do you agree with this statement?
Statement: The steeper the concentration gradient, the faster the particles will move.
Yes, agree.
This is equally relevant to diffusion. The steeper the concentration gradient, the faster the rate of diffusion is for that substance.
What is diffusion?
Diffusion is the net movement of particles (ions or molecules) from a region where they are of higher concentration to a region where they are of lower concentration, that is, down a concentration gradient.
What is dynamic equilibrium?
when the rates of the forward and reverse reactions are equal. The system is dynamic because individual molecules react continuously. It is at equilibrium because no net change occurs.
What is a permeable membrane?
A permeable membrane is a membrane that allows both the solvent (water) and the solutes (the dissolved substances) to pass through it.
If there are 2 substances being dissolved in the same liquid, will they be dissolved separately?
No. If there is more than one substance dissolved in the same liquid, then the dissolved particles of one substance will diffuse independently of the other.
The cell of our lungs exchange oxygen and carbon dioxide through diffusion/ osmosis?
Diffusion. Because this is a exchange of gas.
Why is the cell surface membrane a partially permeable membrane?
The cell surface membrane is a partially permeable membrane. This is due to the fact that it allows only certain substances to pass through but not others.
What is water potential?
Water potential is a measure of the tendency of water to move from one place to another.
Does concentrated solution contain more water molecule than saturated solutions?
Yes
How is water potential gradient established?
It is when a partially permeable membrane separates two solutions of a different water potentials.
What is osmosis?
Osmosis is the net movement of water molecules from aa solution of higher water potential to a solution of lower water potential, through a partially permeable membrane.
What is the term used when 2 solutions are of the same concentration, and have the same water potential?
Isotonic
What is another term used for concentrated solutions?
Hypertonic
What is another term used for a diluted solution?
Hypotonic
Why does plant cell behave differently from an animal cell when placed in solutions with differing water potentials?
This is because of the presence of the cell wall in plant cells.
Why will plant cell not burst even when placed in a solution with higher water potential?
This is because the cell is protected by the inelastic cell wall.
What happens to a cell in a solution of the same water potential? why?
Cells immersed in a solution with the same water potential as their cytoplasm will not change their size and shape.
This is because there is no water potential gradient established since the concentration of water potential in cytoplasm and the solution is the same.
What is plasmolysis?
Plasmolysis is the shrinkage of cytoplasm and cell membrane away from the cell wall.
How can you restore original shape in plant cells that are being plasmolysed?
The cell can be restored to its original state by placing it in a water or in a solution with higher water potential.
What is crenation?
Crenation is a process whereby animal cells shrinks and little spikes appear on the cell surface membrane due to it being dehydrated.
What happens when there is a high rate of evaporation of water from plant cells?
The cells in plants lose turgidity and the plants wilts.
Why is turgor important in plants?
Turgor plays an important role in maintaining the shape of soft tissues in plants. This can be seen in most leaves and young stems, especially those of the herbaceous and non-woody plants, are able to remain firm and erect because of the turgor pressure within the cells.
Cells become limp or flaccid because of the process ___.
Plasmolysis.
