Lab 2

Question 1

Diffusion

Answer 1

The movement of particles down their concentration gradients from an area of high to low concentration

Question 2

What is osmosis

Answer 2

The diffusion of water down its concentration gradient

Moves to area with less available water

Question 3

Isotonic solution

Answer 3

Equal concentration of solute in the 2 environments being compared
Ex:no osmotic flow occurs in red blood cells in a isotonic solution

Question 4

Hypotonic solution

Answer 4

Lower solute concentration in solution compared to inside the cell(therefore water moves in and expands the cell)
Ex: a red blood cell would swell up in a hypotonic solution

Question 5

Hypertonic solution

Answer 5

Higher solute concentration in solution than compared to inside the cell(therefore water moves out and cell gets smaller)
Ex: red blood cells shrivel up in hypertonic solutions

Question 6

Crenation

Answer 6

Cells immersed in a hypertonic solution will shrink due to a loss of water

Question 7

Lysis

Answer 7

Cells immersed in a hypotonic solution will burst because water flows rapidly into their cytoplasm

Question 8

Effect of concentration on gradient

Answer 8

Higher concentrations = faster rate of diffusion

Question 9

What happens to the rate of diffusion over time

Answer 9

Diffusion is directly proportional to concentration therefore rate depends on concentration gradient
After substance has diffused Molecules will move around in a space but their will be no net movement of molecules from one are to to another because they will be in dynamic equilibrium

Question 10

What happens when an erythrocyte is placed in a solution with 2 mL of 1.8 / 3.6 % NaCl

Answer 10

Crenation occurs (mixture is opaque)

Question 11

What happens when an erythrocyte is placed in a solution with 2 mL of 0.45 % NaCl

Answer 11

Lysis occurs (mixture becomes transparent)

Question 12

What happens when an erythrocyte is placed in a solution with 2 mL of 0.9 % NaCl

Answer 12

Opaque mixture and no change to red blood cell structure because isotonic solution

Question 13

What did you do during lab 2

Answer 13

We measured the diffusion of different concentrations of potassium permanganate (KMNO4) through agar at room temperature
Diffusion occurs faster in water
Also what happens to a red blood cell in a solution with different concentrations of NaCl
Observed brow Ian motion

Question 14

The presence of erythrocytes in a mixture will make the red liquid opaque(light is scattered as it passes through). Explain why the erythrocyte suspension in some of the tubes changed from opaque to transparent

Answer 14

The solution is opaque due to the presence of red blood cells hence the light is scattered as it passes through. When the solution is transparent light is no longer scattered and the presence of red blood cells disappears because the red blood cells rupture.

Question 15

What is Brownian motion

Answer 15

The random movement of particles in a fluid due to their collisions with other atoms or molecules

Question 16

Brownian motion(a sample of glass particles of varying sizes examined using the compound microscope) explain what is causing the glass particles to move

Answer 16

The water molecules(that we can’t see) are moving and crashing into the bits of glass particles which cause the glass particles to move

Question 17

Describe the effect of molecule size on diffusion through a semipermeable barrier

Answer 17

If molecules moving down a concentration gradient are too large to fit through the spaces between the bilayer they must undergo facilitated diffusion.