Light travels in electromagnetic waves. Wavelengths, the distance between the crests of the electromagnetic waves, can range from nanometers to kilometers. Visible light is a narrow band from 380nm to 750nm and is necessary for life [AP Biology Eighth Edition]. Autotrophs capture sun energy and convert it into chemical energy. This is called photosynthesis. Photosynthesis takes place in two stages: light reactions and the Calvin cycle. In light reactions, water is split, which creates electrons and releases oxygen as a byproduct [Mr.Orlinsky’s lectures]. This reaction also reduces NADP to NADPH. Light is absorbed by chlorophyll, and this causes electrons to jump to a higher electron level and create ATP. ATP and NADPH move to the stomata to take part of the Calvin cycle. During the Calvin cycle, CO2 molecules are turned into organic molecules. The photosynthesis equation is:
6CO2 + 6H2O + sunlight → C6H12O6 + 6 O2
In this experiment, we are going to use leaf disks to measure the net rate of photosynthesis under different light colors. The leaf disks float until their air bubbles are drawn out and replaced with the surrounding solution, causing their density to increase and the disk to sink. With enough light energy, photosynthesis will take place. Sugar will be made and oxygen will be released as a byproduct, causing the disks to float again. The rate of photosynthesis can be measured by the buoyancy of the leaf disk indirectly [AP Biology Lab Manual for Students].
Photosynthesis- The chemical process of turning sun energy into energy
Autotrophs- an organism capable of synthesizing its own organic substances from inorganic compounds, sustaining themselves without eating anything from another living being
Chloroplast- major plant organelle that contains chlorophyll; Photosynthesis takes place here.
Rate- A measure, quantity, or frequency, typically one measured against...