Question

C Adding your Reagents HyA-TAA IS S Put on your safety goggles. 1. 2. Add 6.0 ml of distilled water (dH2O) to culture tube 1 equivalent to 0.00 M NaCl (aq)) (0.0% NaCl (aq) is 3. Add 6.0 ml of 0.3% NaCl (aq) solution to culture tube 2 equivalent to 0.05 M NaCl (aq)). (0.3% NaCl (aq) is 238 4. Add 6.0 ml of 0.6% NaCl (aq) solution to culture tube 3 equivalent to 0.10 M NaCl (ag)) (0.6% NaCl (aq) is 265 5. Add 6.0 ml of 0.9% NaCl (aq) solution to culture tube 4. equivalent to 0.15 M NaCl (aq). (0.9% NaCl (aq) is Fnte thin Imi 6. Add 6.0 ml of 5.0% NaCl (aq) solution to culture tube 5 equivalent to 0.86 M NaCl (aq)). (5.0% NaCl (aq) is gester thunlan 7. Add 6.0 ml of 10.0% NaCl (aq) solution to culture tube 6. equivalent to 1.71 M NaCl (aq)). (10.0% NaCi (aq) is 8. Set the clock to zero. gleater thm/h 9. Retrieve your laboratory gloves, and several transfer pipettes. 10. Put on your safety goggles and laboratory gloves. 11. Retrieve the bottle of ice-cold sheep blood. 3. In which of the culture tubes did RBCS disappear? What happened to the cells? What is the general description of the solute concentration of this solution? What is the numerical concentration in percent and molarity? What is the tonicity of this environment relative to the internal concentration of the RBC?

Answer 1

0.9% solution of NaCl is said to be isotonic for the survival of RBC. In this salt solution, there is no movement of water and there is said to be an osmotic equilibrium with no movement of salt ions and water from the external environment to the inside of the RBC and vice-versa. The RBC cells will disappear with swelling and bursting if they are put in a salt solution containing equal to or more than concentration of 0.4% NaCl. This will happen in test tube number 4. The water will enter the RBC from the external environment causing the swelling of the cell membrane leading to the rupturing of the cell membrane and cell wall. The general description of the salt solution is the concentration or the amount of sodium chloride salt dissolved in water to form the required concentration of the salt ions. For example if the concentration of the salt ions is 0.4%, then it means that 0.4 gm of sodium chloride has been dissolved in 100 ml of water to obtain the required concentration of the salt ions. If the concentration of salt ions is above 1.8% then it will cause the crenation or shrinking of the red blood cells due to the movement of water from the inside of the red blood cells towards the outside medium causing the shrinking or the crenation of the shape of the red blood cells. If RBC is dipped in salt solution of concentration 0.4% then it is said to be hypotonic condition, if the salt concentration is above 1.8% then it is said to be hypertonic condition and if the concentration of salt ions is 0.9% then it is said to be an isotonic condition of the salt in the required medium.

If concentration of salt is 5% then it means 5gram of NaCl salt is dissolved in 100 m of water.

Molarity - number of moles of solute dissolved per liter of water solution.

Number of moles= mass in grams of solute/ molecular weight of the solute.

=5/ 58.44= 0.085 moles.

Moleculr weight of NaCl= 58.44.

If the volume of solution water is 100ml then the molarity of 5% NaCl will be equal to = 0.085 x 1000 ml / 100 ml = 0.85M.

The swelling and bursting of RBC will take place in test tube number 3 and test tube number 4.