Osmosis and diffusion

Question 1

What is passive transport?

Answer 1

the movement of molecules through a semipermeable membrane and concentration gradient without the help of energy

Question 2

What is diffusion?

Answer 2

The movement of molecules down their concentration gradient. Non-polar and small molecules can freely diffuse across the plasma membrane.

Question 3

What is facilitated diffusion

Answer 3

When the molecules are polar or are too big to pass through the membrane alone so they can use membrane protein.

Question 4

What is a protein channel?

Answer 4

pores or holes in the membrane that help make move down their concentration gradient in or out of the cell.

Question 5

What is a Carrier Protein?

Answer 5

a protein that attaches to a substance that is being transported and undergo a conformational change to push the substance down its concentration gradient.

Question 6

What is Osmosis?

Answer 6

The diffusion of water from an area of low solute concentration to an area of high solute concentration

Question 7

What is the difference between Solute, Solvent and Solution?

Answer 7

Solute: eg. salt or sugar
Solvent: eg. water
Solution: mixture or both

Question 8

Why can water molecules move through the plasma membrane even though they are hydrophilic?

Answer 8

Because they are small enough to pass through.

Question 9

What is tonicity?

Answer 9

The measure of the relative concentration of solutes on either side of the plasma membrane

Question 10

What is a hypertonic solution?

Answer 10

If a cell is placed in a hypertonic solution water will leave the cell to balance out the higher concentrated solution on the outside of the cell.The cell will end up shriveling due to the vacuole losing water.

Question 11

What is a hypotonic solution?

Answer 11

If a cell is placed in a hypotonic solution then water will flow into and fill the cell due to the intracellular fluid having a higher solute concentration to the extracellular fluid.

Question 12

What is an isotonic solution?

Answer 12

If a cell is placed in an isotonic solution there will be equal water flow in and out of the cell due to the concentration of the extracellular fluid and intracellular being balanced.

Question 13

What is active transport?

Answer 13

The movement of molecules across a semipermeable membrane with the helps of pumps and energy against the concentration gradient.

Question 14

Why is protein mediated active transport needed?

Answer 14

It is needed when there is a difference in concentration gradients of the substances inside and outside of the cells.

Question 15

What does all molecule transportation against its concentration gradient need?

Answer 15

• Energy ( usually ATP )
• Membrane proteins to help the substances through

Question 16

What are the three steps of active transport?

Answer 16

1. Binding - the target molecule being transported binds to a specific protein pump
2. Conformation Change - Due t energy being released as a result from ATP→ADP+Pi, a conformational change in the protein pump is caused. the energy comes from breaking the bond between the second and third phosphate ion in ATP molecule.
3. Release - target molecule is pushed through to the other side of the membrane.