biologyRP3 · Cell BiologyPaper 1Combined and Separate

Osmosis in plant tissue

Method overview

Cut equal potato cylinders, measure initial mass, place each in a different known concentration for the same time, remove, blot in a standard way and reweigh. Calculate percentage mass change and plot against concentration.

Apparatus set-up

Diagram

potato cylinders; cork borer; ruler; balance; labelled tubes; sugar/salt solutions; paper towel; timer

Independent variable

solution concentration

Dependent variable

change or percentage change in tissue mass

Control variables

initial cylinder dimensions; tissue source; solution volume; time; temperature; blotting method

Apparatus

potato cylinders; cork borer; ruler; balance; labelled tubes; sugar/salt solutions; paper towel; timer

Safety

Cut away from fingers and handle glassware/solutions carefully.

Scientific rationale

Water moves through partially permeable cell membranes from higher water concentration to lower water concentration. Blotting removes surface liquid so only tissue mass is measured.

You will work through 12 questions across four layers — Core, Deepen, Exam and Transfer Challenge. Hints reveal in two stages, and the model answer only appears once you ask for it. Mark yourself honestly at each question so your mastery-by-skill breakdown stays accurate.