Unit 2 Osmosis and Water Potential

What is tonicity?

Ability of an extracellular solution to cause a cell to gain or lose water

What does tonicity depend on?

Concentration of solutes that cannot pass through the cell membrane 

What are the three types of solutions cells can be immersed in?

Isotonic, hypertonic, and hypotonic solutions

What is osmoregulation?

Process in which cells regulate their solute concentrations and maintain water balance

What will react differently to osmosis when compared to cells with cell walls?

Animal cells

What are examples of cells with cell walls?

Plant, fungus and some protist cells

What will cells immersed in an isotonic solution have?

No net movement of water

How does the concentration of nonpenetrating solutes inside the cell compare to the concentration of nonpenetrating solutes outside the cell?

Both are equal to one another

How does water diffuse into the cell in isotonic solutions?

At the same rate water moves out of the cell

What kind of solution do animals cells work optimally in?

Isotonic solutions

What will happen to plant cells in isotonic solutions?

Will wilt and become flaccid 

Why do plant cells wilt and become flaccid when immersed in isotonic solutions? 

There’s a lack of turgor pressure 

What do cells immersed in hypotonic solutions do?

Lose water to their extracellular surroundings 

How does the concentration of nonpenetrating solutes inside the cell compare to the concentration of nonpenetrating solutes outside the cell in hypertonic solutes?

Higher outside of the cell

What will water move to in hypertonic solutions?

Extracellular fluid 

No cells can work optimally in hypertonic solutions.

True

What is plasmolysis?

Shrinkage of the central vacuole due to loss of water

What happens in plasmolysis in concerns to the plasma membrane?

Pulls away from the cell wall

What do cells immersed in hypotonic solutions do?

Gain water

How does the concentration of nonpenetrating solutes inside the cell compare to the concentration of nonpenetrating solutes outside the cell in hypotonic solutions?

Lower outside the cell 

What will cells gain in hypotonic solutions?

Water

What will happen to animal cells immersed in hypotonic solutions?

Will swell and lyse 

What solutions to plant cells work optimally in?

Hypotonic solutions

Why do plants cells work optimally in hypotonic solutions?

Maintains turgor pressure 

What is water potential?

Physical property that predicts the direction water will flow 

What impacts water potential?

Solute concentration and physical pressure

What will water flow from in concerns to water potential?

Areas of high water potential to areas of low water potential

What will water flow from in concerns to solute concentration?

Areas of low concentration to areas of high solute concentration

What will water flow from in concerns to pressure?

Areas of high pressure to low pressure 

What symbol represents water potential?

Ψ

What formula can be used to find water potential?

Ψ_s + Ψ_p

What does Ψ_s represent?

Solute potential

What does Ψ_p represent?

Pressure potential 

What decreases water potential?

An increase in solute potential

What is solute potential?

Component of water potential that measures the tendency of water to move into a solute based on solute concentration

What is solute potential always?

A negative number

Why is solute potential always a negative number?

Because as solutes are added to free water, they bind to water molecules, which reduces the capacity of water to move and do work

What formula can be used to find Ψ_s?

-iCRT

What does i represent in the solute potential formula?

Ionization constant 

What is the ionization constant if no ions are formed?

0

What does the C represent in the solute potential formula?

Molar concentration

What does the R represent in the solute potential formula?

Pressure constant

What pressure constant should be used in the solute potential formula when a solution is exposed to the open air?

0.0831

What does C represent in the solute potential formula?

Temperature in Kelvin 

How can temperature in Kelvin be found?

By adding 273 to temperature in degrees Celsius