B1b Flashcards
What is diffusion?
The spreading out of a gas or solution in a net movement from high to low concentration.
What is the name for the diffusion of water from a dilute to concentrated solution through a partially permeable membrane?
Osmosis.
What is active transport?
The movement of substances from a dilute to a more concentrated solution, requiring energy from respiration.
Why does a single-celled organism have a relatively large surface area to volume ratio?
To allow sufficient transport of molecules in and out of the cell.
What is a feature of gills in fish?
Large surface area / thin membrane / efficient blood supply / good ventilation.
Why is a thin membrane important?
It provides a short diffusion path.
What is an advantage of alveoli in the lungs?
Increases surface area.
What is the role of the stomata?
To allow ventilation; letting gases in and out.
Where is villi found?
In the small intestines.
How do you work out the surface to volume ratio?
Surface area / volume.
