Module 11 Flashcards
Osmosis, Tonicity, Osmoregulation
Molarity
the concentration of a solute in a solution
Permeable
When a membrane allows water or solutes to diffuse through it freely
Impermeable
When a membrane blocks the diffusion of water and solutes entirely
Selectively Permeable
Allows the movement of some molecule but not others
Aquaporins
Allows water to diffuse freely across the cell membrane at a rate much faster than would be possible by simple diffusion alone
How does water move across the cell membrane
Diffusion, through the concentration gradient
Concentration gradient
High to low water concentration
Solute concentration is low so
Water concentration is high
Water concentration is low
Solute concentration is high
How does water more in relation to solute concentration
water moves from low solute concentration to high
Osmosis
The movement of water across a SELECTIVELY PERMEABLE membrane in response to a difference in water concentration
What is osmosis a response too
The solute concentration inside the cell in relation to the outside
Equilibrium
When the concentration of solutes is the same on the 2 sides of the membrane
Net movement during equilibrium
stops although water molecules continue to move in both directions
Water potential
All of the chemical and physical properties that affect the movement of water, such as osmosis pressure and gravity
Water moves towards what kind of water potiental
Water goes towards more negative water potential
Osmotic Pressure
the tendency of water to move from one solution into another by osmosis
the tendency of a solution to draw water in by osmosis
Cell has an increased external pressure, or decreased internal pressure
Hydrostatic pressure
the pressure that gravity exerts on the solution
Water moves to
Higher solute concentration
Tonicity
How strongly water is pulled into one solution compared to another
“strength” describes osmotic pressure and the direction of water movement
Higher Tonicity
Has higher solute concentration
Draws water in by osmosis
Hypertonic
Solution with a higher solute concentration than another
Hypotonic
Solution with a lower solute concentration than another solution
Isotonic
Solution has the same solute concentration as another solution
Hypertonic relative to the inside of the cell
Water leaves cell by osmosis
Hypotonic relative to inside of the cell
Water moves into the cell by osmosis and swells
Less salt outside
What causes Lyse
Hypotonic relative to the inside of a cell
Lyse
Burst/ rupture
Isotonic relative to inside of the cell
cell/ homeostasis
Paramecium
A unicellular eukaryote that lives in freshwater
Extracellular environment is hypotonic relative to the cells interior
Face risk of lysis, has contractile vacuole
Contractile vacuole
Takes up excess water from inside the cell, and expels it by contractionion into the external environment
Turgor Pressure
the force exerted by water pressing against an object
What is turgor pressure resulted from
Water moving by osmosis into cells surrounded by a cell wall
IN PLANTS, BACTERIA, FUNGI, AND PROTISTS
Osmoregulation
regulates the osmotic pressure inside a cell and organism
High osmotic pressure
Damage/ lyse cell
Low osmotic pressure
dehydration
Osmoconformers
Animals that keep their internal fluids at the same osmotic pressure as the surrounding environments
Live in areas of stable solute concentration= sea water
Urea
Waste product of protein metabolism that many animals excrete
Sharks and rays retail this solute to achieve osmotic equilibrium w /surrounding sea water
