3: Movement into and out of cells Flashcards
Describe diffusion
The net movement of particles from a region of their higher concentration to a region of their lower concentration (i.e. down a concentration gradient) as a result of their random movement
Where does the energy for diffusion come from?
It comes from the kinetic energy of random movements of molecules and atoms
How do some substances move into and out of cells?
By diffusion through the cell membrane
Describe the importance of diffusion of gases and solutes in living organisms
Which factors affect the rate of diffusion
Surface area, Temperature, Concentration gradient and Distance
How does surface area affect the rate of diffusion?
The greater the surface area, the higher the rate of diffusion
How does temperature affect the rate of diffusion?
The higher the temperature, the higher the rate of diffusion
How does the concentration gradient affect the rate of diffusion?
The greater the difference in concentration, the higher the rate of diffusion
How does distance affect the rate of diffusion?
The shorter the distance, the higher the rate of diffusion
What type of membrane that water diffuses through during osmosis?
A partially permeable membrane
In what state is a plant cell in when it is in a solution of lower water potential?
Flaccid
In what state is a plant cell in when it is in a solution of equal water potential?
in equilibrium
In what state is a plant cell in when it is in a solution of higher water potential?
Turgid
Why do plants wilt?
When plants aren’t given enough water, the cells inside the leaves and stem become flaccid and droop.
In what state is a animal cell in when it is in a solution of lower water potential?
Crenation (or the cell is crenated)
In what state is a animal cell in when it is in a solution of equal water potential?
in equilibrium
In what state is a animal cell in when it is in a solution of higher water potential?
Haemolysis (the cell is haemolytic)
Since animal cells do not have a cell wall, they will keep expanding until they burst
What is turgor pressure?
The force that presses the cell membrane of a plant cell to its cell wall
What is plasmolysis?
When the plant cell loses water to a solution of lower water potential, and becomes flaccid
Define active transport
The movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration (i.e. against a concentration gradient), using energy from respiration
Why is active transport so important?
It is a process for movement of molecules or ions across membranes, including ion uptake by root hairs
What do protein carriers do?
They move molecules or ions across a membrane during active transport
Describe how active transport plays a role in the uptake of mineral ions by plants
When the concentration of an ion is greater inside the cell than in the soil water, the plant has to use active transport for ion uptake
Describe how active transport plays a role in the uptake of glucose by animals
When the concentration of glucose in the blood is higher than in the gut lumen, epithelial cells will need to use active transport to absorb glucose
