REQUIRED PRACTICAL: PHOTOSYNTHESIS

WHAT IS PHOTOSYNTHESIS

The process by which plants synthesis glucose using light energy from the Sun

DESCRIBE HOW YOU WOULD INVESTIGATE THE RATE OF LIGHT INTENSITY ON RATE OF PHOTOSYNTHESIS IN AN AQUATIC PLANT

Place cut pondweed in a boiling tube (contains solution) at a fixed distance from a light source
Count number of bubbles produced in one minute using stopwatch
Repeat several times at different distances/light intensities, Calculate a mean for each distance
Plot a graph of light intensity against rate of photosynthesis, bubbles per minute

WHY IS IT BEST TO USE AN LED LIGHT SOURCE RATHER THAN A LAMP

A lamp will emit more heat energy than an LED - therefore it may change the temperature of the experiment and affect the rate of photosynthesis

WHAT IS THE RELATIONSHIP BETWEEN DISTANCE FROM LIGHT SOURCE AND LIGHT INTENSITY

light intensity = 1/distance^2

HOW CAN THE MEASUREMENT OF OXYGEN PRODUCTION BE MADE MORE ACCURATE

If the pondweed is placed under a filter funnel with measuring cylinder upside down over the sprout, volume of oxygen produced can be determined

WHY IS SODIUM HYDROGEN CARBONATE SOLUTION USED DURING THIS EXPERIMENT

It releases CO2 which is used by the pondweed during photosynthesis

WHY CAN THE NUMBER OF BUBBLES PRODUCED BE USED TO CALCULATE THE RATE OF PHOTOSYNTHESIS

Oxygen bubbles are formed as a product during photosyntheis therefore the number of bubbles produced in a given time is proportional to the rate of photosynthesis