K.C.S.E Biology Q & A - MODEL 2000PP1QN15

K.C.S.E Biology Q & A - MODEL 2000PP1QN15

The concentration of the lactic acid in blood during and after an exercise was determined. The results are shown in the graph below

(a) (i) By how much did the lactic acid increase at the end of 13 minutes?
(ii) After how many minutes was the lactic acid concentration 71mg/100cm3?
(iii) What would be the concentration of lactic acid at the 60th minute?
(b) Give a reason for the high rate of production of lactic acid during the Exercise
(c) Give a reason for the decrease in the concentration of lactic acid after the exercise

answers

​(a) (i) 78/78 mg/ 100cm3
(ii) 8.5th and 29.5th / 8min 30 sec and 29 min 30 sec
(iii) 47 mg/100cc; Acc. 47
(b) The demand for oxygen is more than the supply
    leading to anaerobic respiration. Acc. Lactic acid converted to glucose/Glycogen
(c) Lactic acid is oxidized ( to form CO2 and H2O)
Acc. Lactic acid is converted to glucose/ glycogen