1. Osmosis and plant transport Flashcards
what is osmosis
movement of water molecules from dilute to more concentrated solution, through a selectively permeable membrane
Describe what will happen to an animal cell such as red blood cell when placed in a dilute solution (or pure water)
Water will enter the red blood cell by OSMOSIS
As it is more dilute outside the cell than inside the cell (down concentration gradient)
The red blood cell will expand and eventually burst - this is CELL LYSIS
Describe what will happen to an animal cell such as red blood cell when placed in a concentrated solution
Water will LEAVE the cell by osmosis as more dilute inside cell than outside.
The cell will shrink and is described as CRENATED
Describe what will happen to a plant cell when placed in a dilute solution (or pure water)
Water will ENTER the plant cell by OSMOSIS
The vacuole will get larger
The cell membrane will push against cell wall
The cell is describe as being turgid
Describe what will happen to a plant cell when placed in aconcentrated solution
Water will LEAVE the plant cell by OSMOSIS
The vacuole will shrink
The cytoplasm and cell membrane move away from the cell wall
Cell is PLASMOLYSED
Why do animal cells burst but plant cells do not burst when placed in pure water
Plant cells have a cell wall
If reading a graph that shows concentration of solution and the % change in mass/length of potato. How can you work out the concentration of the potato
Read the graph where it crosses the x axis - this tells you the concentration of the solution when there was no change in mass/length = this means there was no net movement of water into or out of the cells at this concentration
How do mineral ions enter a plant
Through the roots
By active transport (against concentration gradient)
What is a potometer
A piece of equipment used to measure the rate of water uptake in a plant
How do you measure the rate of water uptake in a potometer
use a stopclock to time how long it takes the bubble to travel a certain distance along the tube towards the plant
Then calculate distance per unit time eg cm per min
What is transpiration
Evaporation of water from mesophyll cells followed by diffusion through airspaces and stomata
What factors affect the rate of transpiration
Light intensity
Temperature
Humidity
Surface area of leaf
Wind
Describe how light intensity affects rate of transpiration
As light intensity increases the rate of transpiration increases - this is because more stomata are open as more photosynthesis occurring (so more Carbon dioxide enters the leaf)
But as more stomata open then more places for water to diffuse out of
Describe how temperature affects rate of transpiration
As temperature increases the rate of transpiration increases - this is because more particles gain more kinetic energy so water molecules leave the leaf at a faster rate
Describe how humidity affects rate of transpiration
As humidity increases the rate of transpiration decreases - this is because more water molecules in surrounding atmosphere so concentration is less steep between inside of leaf and outside - less movement of water
