B1 Cells And Organisation Flashcards
What is diffusion
The net movement of particles from a area of high concentration to an area of low concentration, due to the random movement of particles and this is done as a passive process, so it does not use any energy
What happens in diffusion
Particles from a area of high concentration move to area of low concentration (net movement) due to the random movement
Why is diffusion important
Because we take in oxygen through diffusion, as it’s how oxygen particles mixes with the air
Why do multicellular organisms need exchange systems and transport systems
Because their surface area to volume ratio gets smaller and so they can’t take in everything that they need for their cells in simple diffusion so they have adaptations to make it more efficient
In which states can molecules diffuse
Liquid and gas
What is the difference between two areas in concentration called
The concentration gradient
Name three factors of diffusion
Concentration gradient, temperature and surface area
How do you get fast diffusion
With higher temperature, larger surface area and a larger concentration gradient
What happens to the surface area to volume ratio as an object gets bigger
The ratio falls
Why is a large surface area good for diffusion
Because there is more space for diffusion
Why is osmosis important
Because plants rely on this movement of water
What is active transport
When particles move up the concentration gradient and for this energy is needed
What is osmosis
Osmosis is the movement of water
molecules across a partially
permeable membrane from a region
of higher concentration to a region
of lower concentration.
Where does the energy used for active transport come from
Respiration
How is the energy used in active transport
To open the gates of a cell so that the molecules outside the cell can enter the cell
Which methods require a membrane
Active transport and osmosis
What stops a cell from bursting in osmosis
A cell wall
What is a turgid cell
When the vacoule fills up all the space and pushes against the cell wall, this happens when water moves in a plant
What happens when water moves out of a cell in osmosis (with a cell wall)
The cell becomes flaccid, becoming much smaller and taking up less space and if a lot of water leaves the cell the cytoplasm starts to peel
Why can a animal cell burst if too much water comes in
Because they have no cell wall
What does dilute mean
More water
What does a more concentrated solution mean
Less water
What is a eukaryotic cell?
Cells that have a nucleus
What is a prokaryotic cell
So that does not contain a nucleus e.g a bacterial cell
