osmosis

osmosis

osmosis

 The movement of water molecules through a selectively permeable membrane from a region of high water concentration to low water concentration

Functions of Membranes

• Selectively permeable - allows some molecules in, others are kept out

• Control incoming and outgoing substances

Multiple Choice

Which statement best describes the cell membrane?

• The protective outer layer that controls what enters and leaves the cell.
  
• Stores information on DNA molecules / Directs and controls the activities of the cell.
  
• A folded membrane that moves materials around inside cells / Also acts as the site of manufacturing materials needed by the cell.
  
• The smallest organelle with a huge job / Makes proteins, which are the building blocks of the body.
  

Passive Transport:

 Osmosis

• •Osmosis: diffusion of water through a selectively permeable membrane

• •Water moves from high to low concentrations

Multiple Choice

During osmosis

• water moves from high to low concentration
• large or oddly shaped molecules move across a cell membrane
• water moves when energy is used
• proteins are built

Multiple Choice

Osmosis is the movement of _____ across a membrane.

• food
• energy
• oxygen
• water

Tonicity is a relative term

• •Hypotonic Solution - One solution has a lower concentration of solute than another.

• •Hypertonic Solution - one solution has a higher concentration of solute than another.

• •Isotonic Solution - both solutions have same concentrations of solute.

Solution

• Water moves from inside the cell into the solution:  Cell shrinks 

• Water moves equally in both directions and the cell remains same size! 

• Water moves from the solution to inside the cell): Cell Swells and bursts open 

Multiple Choice

A person would never have pure water put into their veins in a hospital because their cells would...

• Shrink/Dehydrate
• Expand

Multiple Choice

What is diffusion?

• when molecules move 
• when molecules move from a high concentration to a low.
• no movement 
• molecules move everywhere

Multiple Choice

Osmosis is the diffusion of _____________ across a cell membrane.

• Air

• Oxygen

• Water

• Food

Multiple Choice

Why can't you drink salt water?

• It's hypertonic to your cells

• It's hypotonic to your cells

• It's isotonic to your cells

• It's paratonic to your cells

Multiple Choice

Ideally, your cells should be in a(n) _______ solution

• Hypertonic
• Hypotonic
• Isotonic
• Cola

Multiple Choice

An animal cell placed in a hypertonic (salty) solution will

• Shrink
• Swell
• Stay the same