Cell Transport (Passive Edition)

Cell Transport (Passive Edition)

Let's review before you start your lab...

What do you notice?

Concentration Gradients

• The motion of each molecule is random and independent of the other molecules in solution.

• Barring outside influence, molecules have a net movement from an area of high concentration to an area of low concentration.

Multiple Choice

Which side has a higher concentration of molecules?

• M

• Q

Multiple Choice

The net movement of molecules would be from...

• M to Q

• Q to M

Open Ended

Explain what happened to the dye in the water over time.

Simple Diffusion

Movement of small or uncharged molecules down the concentration gradient directly through the cell membrane.

example: O₂ or CO₂

Facilitated Diffusion

Movement of larger or charged molecules down the concentration gradient through a transport protein.

The transport protein is specific to the molecule crossing the membrane.

examples: glucose, Na⁺, Cl^-, K⁺

Multiple Select

When would molecules need proteins to cross the membrane?

• If they're too large to get through the phospholipid bilayer

• If the molecule has a charge.

• If the molecule is too small to get through the phospholipid bilayer.

• If the molecule does not have a charge.

Osmosis

• type of facilitated diffusion

• movement of water across the membrane through a special transport protein (an aquaporin)

• net movement of water is down water's concentration gradient

Fill in the Blanks

Fill in the Blanks

Multiple Choice

If a cell is placed in a hypertonic solution, what would happen to the cell?

• Nothing.

• The cell would increase in size because water is moving into the cell.

• The cell would decrease in size because water is leaving the cell.

Open Ended

You want to find out the exact concentration of salt in a cell. How could determine the osmolarity of a cell?