Unit 1: cholera and exchange Flashcards
What is facilitated diffusion?
When particles are helped by protein channels to pass through the cell membrane
At what point does diffusion/ osmosis stop?
When equilibrium is met
What three things affect diffusion?
- concentration
- thickness of membrane
- surface area
How do you calculate the speed of diffusion?
SA x difference in conc. / length of pathway
Why is facilitated diffusion passive?
No energy is required
Why do some cells diffuse via the protein channels?
They’re soluble and so would dissolve in the phospholipid membrane
What is osmosis?
The movement of water from a less negative water potential to a more negative water potential
What does it mean if something has a more negative water potential?
It has more water
What is active transport?
Where energy is required to move a particle across a concentration gradient
What does ATP do to the protein channel?
It changes the shape so particles can move through it
What is co transport?
Where two molecules move via active transport across the protein channels
How is cholera caused?
A prokaryotic cell that affects the small intestine
How do you treat cholera?
An oral rehydration containing water, sodium ions and glucose
How does oral rehydration hydrate a cell?
Co transport takes glucose into the cell with ions attached to it and then this reduces the water potential. Water is then caused to enter the cell and rehydrate it.
