Studied by 7 peopleWhat does selectively permeable mean?
A cell membrane that allows small molecules through but not larger molecules
What is diffusion?
the movement of molecules from an area of high concentration to an area of lower concentration
What is osmosis?
The diffusion of water from a dilute solution to a more concentrated solution through a selectively permeable membrane
What happens when water moves into a plant cell
The plant cell becomes turgid
What happens to a plant cell in a dilute solution? (Turgid)
Vacuole expands
Cell membrane pushes against cell wall
Causes turgor necessary for support
Cell wall stops membrane expanding too much and limits water intake
Why is presence of a cell wall in plant cells important during osmosis?
Prevents the expansion of the membrane to the point of bursting
Why is this cell type important for a plant?
It limits water intake and provides turgor necessary for support
What happens when water moves out of a plant?
It becomes plasmolysed
What happens to a plant cell when in a concentrated sugar solution? (Plamolysed)
Plant cell loses water
Vacuole becomes smaller
Cell membrane pulls away from wall
Cell is now plasmolysed
What happens to red blood cells in water?
The cells will, take water in by osmosis and burst in a process called cell lysis
Why is movement of water through a plant important?
Support,
transpiration,
transportation
photosynthesis
What is transpiration
The evaporation of water from the spongy mesophyll cells followed by diffusion through the leaf air spaces and the stomata
What are 4 environmental factors that effect the rate of transpiration?
Temperature
wind speed
humidity
light intensity
What is a factor of the leaf that can affect transpiration?
Surface area of leaf.
The greater the surface area, the greater the number of stomata and so the faster the rate of transpiration
What effect does temperature have on transpiration?
In warmer conditions water evaporates faster
What effect does wind speed have on transpiration?
evaporation is faster in higher wind speeds as the wind rapidly removes the evaporating water away from the stomata and leaf surface and the surrounding air
What effect does humidity have on transpiration?
humid conditions restrict evaporation as there is a decrease in the moisture gradient between the leaf surface and surrounding air
What effect does light have on transpiration?
many plants close their stomata in darkness to reduce water loss
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