Cell Structure and Function
Why do freshwater fish excrete large volumes of dilute urine?
They compensate for dietary intake of carbohydrates and proteins that lead to increased metabolic waste production, requiring more flushing to maintain chemical homeostasis.
They use active transport to rid themselves of ions rapidly because being surrounded by lower-ion-content waters makes them vulnerable to toxic buildup.
They expel vast quantities because their kidneys have inefficient reabsorption capabilities evolved specifically to cope with living in environments where liquid resources are abundant and plentifully available.
They constantly absorb excessive amounts of ambient water by osmosis due to their internal saltier conditions relative to their environment, necessitating frequent elimination.
The movement of water can be measured and quantified using the __ equation.
Diffusion
Tonicity
Aquaporin
Water potential
Which term best describes a solution that has a higher solute concentration compared to the interior of an animal cell?
Hydrophilic
Hypotonic
Hypertonic
Isotonic
When a cell is placed in a hypertonic solution, which process will most likely occur?
Water will move out of the cell.
Water will move into the cell.
The solute concentration inside the cell will increase.
Osmoregulators will activate to pump water into the cell.
Which process would most likely result in a net water influx into a freshwater protist living in an environment that has become hypotonic relative to the protist's cytoplasm?
Active transport of ions out of the protist.
Facilitated diffusion of glucose into the protist.
Endocytosis of large particles into the protist.
Osmosis of water out of the protist.
If a cell is placed in an environment with a higher concentration of solutes than inside the cell, which process would it most likely undergo to reach equilibrium?
Lysis, as water enters the cell causing it to swell.
Crenation, as water leaves the cell causing it to shrink.
Plasmolysis, where the cytoplasm pulls away from the cell wall in plants.
Turgidity, as water enters and creates outward pressure on the cell wall.
When water is moved from one side of the plasma membrane to the other, it utilizes special proteins called __.
Osmoregulators
Aquaporins
Channel proteins
Na/K pump

How are we doing?
Give us your feedback and let us know how we can improve
What might be an effect on an animal cell if a mutation led to an overexpression of sodium-potassium pumps?
The cell could swell due to increased potassium levels inside, resulting in lysis.
There may be no change as ion channels balance out the increased activity of pumps.
The cell could become hypertonic with respect to its surroundings, leading to crenation.
The cellular ATP demand might decrease due to enhanced efficiency of ion transport.
Which adaptation would you expect to find in freshwater fish that helps with osmoregulation?
Salt-secreting glands to eliminate concentrated salt solutions
Gills that actively absorb salt from their surroundings
Thick skin that minimizes water absorption
Highly efficient kidneys to excrete excess water
What would cause leaves of a plant to wilt?
If water potential outside of the plant cell is higher than the water potential of the plant cells
If water potential outside of the plant cell is equal to the water potential of the plant cells
If the pressure potential of the leaves increased to 1 Mpa
If water potential outside of the plant cell is lower than the water potential of the plant cells