Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
what is diffusion |
diffusion is the net movement of particles from a higher concentration to a lower concentration |
|
|
what the the relationship between the concentration gradient and the rate of diffusion |
the steeper the concentration gradient for a substance the faster the rate of diffusion |
|
|
what are the factors that affects the rate of diffusion |
concentration gradient diffusion distance sa: vol |
|
|
what is the relationship between the diffusion distance and the time needed for the substance to travel |
the shorter the diffusion distance, the less time is needed for the substance to travel hence rate of diffusion is higher |
|
|
what is the rate of movement across a membrane dependent on |
the rate of movement of a substance across a cell membrane depends on how large the cell membrane is |
|
|
what is the relationship between sa:vol and rate of diffusion |
greater surface area to volume ration higher rate of diffusion |
|
|
what is osmosis |
osmosis is the net movement of water from a region of higher water potential to a region of lower water potential through a partially permeable membrane |
|
|
what is water potential |
water potential is the measure of the tendency of water molecules to move from one place to another |
|
|
what are factors that affect osmosis |
water potential gradient distance over which water molecules need to move sa:vol |
|
|
what happens when the surroundings of a plant cell has a higher water potential than the plant cell |
when a plant cell is placed in a solution of higher water potential,, the cell spa has lower water potential than that of the solution outside by osmosis the water molecules enter the cell through the partially permeable cell membrane the cell will expand or swell as water molecules enter the cell the vacuole increases in size and pushes the cytoplasm against the cell wall the cell doesn’t burst because it is protected by the in elastic cell wall |
|
|
what happens when the surroundings of the plant cell has a lower water potential then the inside of the plant cell |
when a plant cell is immersed in a solution with a lower water potential, the cell sap has a higher water potential than the solution outside of the cell by osmosis the water molecules from the vacuole and cytoplasm leave the cell through the partially permeable cell membrane the cell decreases in size and becomes flaccid or limas the cell loses water the vacuole shrinks in side the cytoplasm shrinks away from the cell wall the plasmolysed cell can be restored to its original state by placing it in a water solution or a solution with a higher water potential |
|
|
what happens when the surroundings of an animal cell has a higher water potential than the cell |
an animal cell may burst in a solution of a higher water potential than its cytoplasm this is due to the lack of a cell wall |
|
|
what happens when the surroundings of the animal cell has the same water potential as the animal cell |
there will be no change in shape or size movement of water molecules is the we in both directions this no net movement of water molecules in or out of the cell |
|
|
what happens when the surroundings of the animal cell has a lower water potential than the animal cell |
the cell will undergo crenation where it loses water and will shrink and spikes will appear on the cell the animal cell becomes dehydrated and may die |
|
|
why is turgor important in plants |
it maintains the shape of soft tissues in plants able to remain firm and erected due to the turgor pressure within the cell |
|
|
what happens when water is being loss at a high rate in a plant |
the plant loses its turgidity and wilts |
|
|
how does the stomata open and close |
the change in turgor of the guard cell causes the opening and closing of the stomata |
|
|
why can’t we add too much fertiliser to the roots of the plant |
the soul becomes very concentrated and water molecules will move out of the cell through osmosis this causes the plant to be plasmolysed and the plant may die the inability for the roots to absorb water and the continued evaporation of water through the leaves will cause the plant to wilt |
|
|
what is active transport |
active transport is the process in which energy is used to move energy particles of a substance across a membrane against its concentration gradient |
|
|
what is the difference between diffusion and active transport |
energy from respiration not required cell membrane not required
energy from respiration required cell membrane required |
|
|
where can active transport occur and why |
in living cells that can respire it isduring respiration that energy is released and part of this energy is used in active transport |
