So one of the flashcards for CLEP Biology has me scratching my head.
"Paramecium and other single-celled freshwater organisms have difficulty since they are usually __________ relative to their outside environment, and under the danger of bursting due to too much water.
Hypertonic. In other words, because they are hypertonic, water is constantly diffusing into the cell. To counteract this, a vacuole (called contractile) absorbs the water from the cytoplasm, and ejects it outside the cell. This is analogous to an airlock in spaceships."
Doesn't diffusion only work from an area of high concentration to an area of low concentration? Hypertonic = higher concentration than surrounding environment. So how is water constantly diffusing into the cell?
I'm confused. Am I wrong? or is this an InstaCert error?
Thank you!
"Paramecium and other single-celled freshwater organisms have difficulty since they are usually __________ relative to their outside environment, and under the danger of bursting due to too much water.
Hypertonic. In other words, because they are hypertonic, water is constantly diffusing into the cell. To counteract this, a vacuole (called contractile) absorbs the water from the cytoplasm, and ejects it outside the cell. This is analogous to an airlock in spaceships."
Doesn't diffusion only work from an area of high concentration to an area of low concentration? Hypertonic = higher concentration than surrounding environment. So how is water constantly diffusing into the cell?
I'm confused. Am I wrong? or is this an InstaCert error?
Thank you!
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