© 2018 noworriesbiology.comAll rights reserved. EXERCISES ON DIFFUSION AND OSMOSIS Topic: Cells

Date:      

1. Give a definition each for the processes of diffusion and osmosis.

     

2. A pirate was shipwrecked and is now floating in the ocean. Although he is quite capable of swimming, his chances for survival aren’t particularly high. He is aware of being in the ironic situation that he finds himself surrounded by water but at the same time being at high risk to die of thirst, if he doesn’t get rescued within the next 24 hours.

Explain why this unfortunate pirate is at high risk of dying of thirst while floating in the sea.

     

Captain Jack Sparrow at Madam Tussauds, London

Vocabulary/Notes:

© 2018 noworriesbiology.comAll rights reserved. EXERCISES ON DIFFUSION AND OSMOSIS Topic: Cells

3. For the functionality of nerve cells (neurons), it is crucial that a disparity in the distribution of sodium ions (Na+) and potassium ions (K+) over their membranes is held upright. Deduce which component of a cell membrane in neurons is responsible for working against an equalization of the ion distribution and therefore in charge of maintaining the necessary ion imbalance.

     

4. When doctors attend to a patient who suffered from severe blood loss, they will order to administer an infusion of 0.9 % sodium chloride (NaCl) solution. If – for any reason – the solution would have another concentration than the one mentioned above, the consequences would potentially be lethal. Our red blood cells (erythrocytes) usually look like shown in picture A. When a sodium chloride infusion with wrongly calculated concentration is administered, they may look like in picture B or C.

A

B

C

Give reasons for the change in shape that can be observed in red blood cells when brought into solutions of various concentrations (A B/ A C), and evaluate the relative concentration of the solution surrounding the blood cells in B and in C (relative to the solution in A).

     

Vocabulary/Notes: