Question

The relationship between oxygen concentration, potassium gain and sugar loss in isolated barley root was determined. The results obtained are given in the table below. (The sugar loss and potassium gain are expressed in arbitrary units).

Percentage oxygen concentration	0	5	10	15	20	100
Sugar loss	15	20	42	45	45	48
Potassium gain	5	55	70	73	75	70

1. Plot on the same axes graphs of sugar loss and potassium gain against oxygen concentrations. 
2.    Suggest the process by which potassium is taken in by the roots. 
3. Give reasons for your answer. 
4. Account for the sugar loss and potassium gain at;
   • 0% oxygen concentration. 
   • Between 5% and 20% oxygen concentration. 
5. Apart from oxygen concentration, suggest two other factors that affect the above process. 
6. State two ways in which you can stop the above process from taking place. 
7. Name one part in human body where the process named in (2) above take place.

Answer 1

1. 
   
2. Active transport;
3. An increase in sugar loss results to an increase in potassium gain/used during respiration to produce energy; Energy used during active transport to gain potassium ions;
4.     
   • Low/no oxygen concentration; less energy produced hence less potassium gain/ uptake;
   • An increase in oxygen concentration; result to an increase in energy production hence an increase in potassium gain/uptake;
5. Temperature; pH; Protein carriers;
6. Depriving the plant of oxygen supply; Treating roots with metabolic poisons; subjecting roots to very high temperature; provision of unfavourable pH;
7. Kidney tubeles;/small intestines;/neurons.