1.2 INVESTIGATION OF THE BUFFERING EFFECT OF THE BLOOD PLASMA

Question 1

what are the most important intracellular buffer

systems?

Answer 1

phosphate (HPO42- / H2PO4-) and the protein (Pr- /HPr)

Question 2

what are the extracellular buffer systems?

Answer 2

carbonic acid/hydrogen carbonate (H2CO3 / HCO3-) and the protein (Pr- /HPr)

Question 3

what does it mean buffer capacity?

Answer 3

as the buffer capacity increase, you can add more acids or bases before the pH changes.

Question 4

what do we need to measure the plasma buffers?

Answer 4

 Blood plasma (3x diluted)
 Physiological saline solution (9 g of NaCl dissolved in 1 l of water)
 Mixed indicator (methyl red 0.2 g, methylene blue 0.1 g dissolved in 100 ml of ethanol)
 Lactic acid (0.02 mol/l)
 Burette
 Beaker
 Pasteur pipette

Question 5

how much physiological saline solution do we need for the measurement

Answer 5

9 g of NaCl dissolved in 1 l of water

Question 6

which indicator do we use for this measurement

Answer 6

methyl red 0.2 g, methylene blue 0.1 g dissolved in 100 ml of ethanol

Question 7

what happens when we add lactic acid

Answer 7

the color changes to reddish violet

Question 8

at what pH the indicator changes its color?

Answer 8

about 4.5