preview

Evaluate The Net Rate Of Photosynthesis

Decent Essays

Introduction: Photosynthesis is the process that converts carbon dioxide into sugars, such as glucose, using energy from the sun and other lights. When light is absorbed by the pigments in the leaf, the energy absorbed is used to incorporate the carbon dioxide into organic molecules in a process called carbon fixation. The equation for photosynthesis in words is carbon dioxide + water (light energy) → Glucose + Oxygen. In numbers it is 6CO2 + 6H2O → C6H12O6 + 6O2. This lab used leaf disks to evaluate the net rate of photosynthesis under various lighting conditions, light, ambient light, and dark. The lab members assessed the leaf responses under sunlight or ambient light. Leaf disks normally float, however when the air spaces are pervaded with carbon dioxide, the overall density of the leaf disk increases and …show more content…

When sodium bicarbonate is added to the water, the bicarbonate ion acts as a carbon source for photosynthesis causing the leaf disks to sink. As photosynthesis proceeds, oxygen is released into the interior of the leaf, which changes its buoyancy causing the disk to rise. Since cellular respiration is taking place at the same time in the leaf, consuming oxygen, the rate that the disks rise is an indirect measure of the net rate of photosynthesis.

The structure of the leaf consists of the upper and lower epidermis, the mesophyll, the vascular bundles, and the stomates (Carter). The upper and lower epidermises serve as protection for the leaf, and the stomates function in air exchange. Carbon dioxide enters through the stomates and oxygen gas exits. The vascular bundles are the plant’s transportation system; all water and nutrients moves via the vascular bundles to different parts of the

Get Access