Osmosis and Diffusion Lab

Question 1

Osmosis

Answer 1

The net movement of water molecules through a semi-permable membrane from an area of higher concentration to an area of lower concentration.

Question 2

Osmosis

Which bag gained the most weight and why did it gain the weight ?

25%, 50%, 75% Karo Experiment

Answer 2

The 75% Karo bag gained the most weight because it had a higher concentration gradient.

Question 3

Osmosis

Which bag gained the least weight and why did it gain the weight?

25%, 50%, 75% Karo Experiment

Answer 3

The 25% Karo bag gained the least weight because it had a lower concentration gradient.

Question 4

Concentration Gradient

Answer 4

The gradual difference in concentration of a dissolved substance in a solution between a region of high density and one of lower density.

https://www.dictionary.com/browse/concentration-gradient

Question 5

At what time was the greatest difference in weight noted? Why is this the case?

Answer 5

The greatest difference in weight was in the first 15 minutes. This is because the concentration gradient was the highest, and at time progressed, the concentration gradient decreased.

Question 6

Dialysis

Answer 6

The diffusion of a solute molecule through a semi-permeable membrane down the solute concentration gradient. This process demonistrates the selective permeability of the membrane, which allows some particles to pass while holding others back.

Question 7

Dialysis

Which solutes passed through the dialysis bag? Why?

Answer 7

Glucose and NaCl passed through because both were small enough to pass through the holes in the membrane. Starch did not pass through because it was too big.

Question 8

Dialysis

Why did the dialysis bag gain weight?

Answer 8

As the solute exited the bag, water also entered the bag.

Question 9

Diffusion

Answer 9

The net movement of particles from a region of high concentration to a region of low concentration until the molecules reach equilbrium. Molecules move down a concentration gradient.

Question 10

Diffusion

What dye moved the most? Why?

Answer 10

The purple dye moved the most. This is because it had the lowest weight/size.

Question 11

Diffusion

How does particle size affect diffusion?

Answer 11

There is an inverse relationship between diffusion and particle size. As particle size increases, diffusion decreases. Simply state, smaller things move quicker.

Question 12

Brownian Movement

Answer 12

Random vibratory movement demonstrated by small particles when suspended in fluid. This movement is caused by the bombardment of the visible particles by the smaller particles of the solvent, which are constantly in motion due to their kentic energy.

Question 13

What happens to a cell in a hypertonic solution?

Cells

Answer 13

If a cell is placed in a hypertonic solution, there will be a net flow of water out of the cell. The cell will lose volume and collapse in on it’s self.

https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/a/osmosis

Question 14

Hypertonic Solution

Answer 14

When the solute concentration outside the cell is higher than inside the cell.

Solutes are unable to cross the membrane.

https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/a/osmosis

Question 15

Hypotonic Solution

Answer 15

When the concentration outside the cell is lower than inside the cell.

Solutes are unable to cross the membrane.

https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/a/osmosis

Question 16

What happends to a cell in a hypotonic solution?

Cells

Answer 16

When the cell is placed in a hypotonic solution, there will be a net flow of water into the cell. The cell will gain volume and possibly burst.

https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/a/osmosis

Question 17

Isotonic Solution

Answer 17

When the solute concentration is the same both inside and outside the cell.

Solutes are unable to cross the membrane.

https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/a/osmosis

Question 18

Tonicity of Red Blood Cells

Answer 18

Crenation, Stable, Hemolysis

https://en.wikipedia.org/wiki/Tonicity

Question 19

Crenation

Red Blood Cells

Answer 19

When red blood cells shrink due to loss of water in a hypertonic solution.

Question 20

Hemolysis

Red Blood Cells

Answer 20

The distruction of red blood cells due gaining too much water in a hypotonic solution.

Question 21

What happens to cells placed in an isotonic solution?

Answer 21

There will be no net movement of water and the cells will retain their orginal shape.