Assignment Task

Introduction

The assignment will be written as a report in standard scientific format. The report is based on a common type of experiment that measures the response of an organism to changes in a the availability of a key resource, or an environmental variable. 

Photosynthesis sustains almost the entire living world directly or indirectly. Almost all plants are autotrophs; specifically, plants are photoautotrophs, organisms that use light as a source of energy to synthesise organic substances. Photosynthesis also occurs in algae, certain eukaryotes (the protists), and some prokaryotes (cyanobacteria).

Many aquatic organisms can use the dissolved gases (such as oxygen and carbon dioxide) in water for respiration or photosynthesis. All aquatic autotrophs, such as plants and algae, perform photosynthesis AND cellular respiration, much like terrestrial plants. In both processes, atmospheric gases (eg. oxygen and carbon dioxide) dissolve into water and are exchanged by autotrophic organisms.

This experiment was designed to study the photosynthesis response to light quantity and quality, and chlorophyll related factors using a uniclelluar green algae, such as Chlorella vulgaris, which photosynthesise in a similar way to C3 higher plants. We can use these algae to investigate some of the factors that affect the rate of photosynthesis. 

As we cannot `see` photosynthesis we are using hydrogen carbonate solution (CO₂ dissolved in water) as an indicator to measure changes in the levels of CO_2 in water which is indicative of CO2 consumption (photosynthesis) and production (respiration).