1.7 Osmosis Flashcards
What is a partially permeable membrane
A membrane that allows only certain substances through that lets water move across them
How does osmosis differ from diffusion?
- In diffusion all particles move freely down concentration gradients.
- In osmosis only water molecules move across a partially permeable membrane from a dilute solution to a concentrated solution.
Give examples of dissolved substances
sugars such as glucose, gases such as oxygen and carbon dioxide and waste products such as urea
what and where is urea found
Urea is produced in the liver when excess amino acids are broken down. It goes from liver cells into blood plasma and excreted by kidneys
Dilute def
a solution which is less concentrated, it contains a higher concentration of solvent and a low concentration of the solute.
What is osmosis
Diffusion of water from a high concentration (dilute) of water to a low concentration (concentrated) across a partially permeable membrane. Requires no energy. It goes down a concentration gradient
Isotonic def
the same concentration of solutes in the solution both inside and outside of the cell.
Hypertonic def
higher concentration of solutes in the solution outside the cell than inside the cell
hypotonic def
lower concentration of solutes in the solution outside the cell than inside the cell
What happens if the cytoplasm becomes more concentrated and the surrounding fluid becomes hypotonic to the animal cell?
Swell and burst because water moves into cell by osmosis. Water moves in.
What happens when the cytoplasm is more dilute and the solution outside the cell becomes hypertonic?
Cytoplasm will become too concentrated and the cell will shrivel up and die
Concentrated def
a solution which is less dilute, it contains a higher concentration of solute and a lower concentration of solvent
