HL Paper 3
Outline what happens when spinach extract is spotted on a TLC plate and placed into a container of solvent.
Explain what the Rf values represent in chromatography.
State two photosynthetic pigments that could be identified using chromatography.
Mean annual chlorophyll concentration was measured in surface water of Narragansett Bay along the Atlantic coast of the USA, from 1971 to 2006. Field data of chlorophyll concentrations are shown below.
Suggest a hypothesis for the trend in the graph.
Mesocosm experiments using water from Narragansett Bay were completed in the laboratory during a six month period. Discuss advantages and limitations of carrying out mesocosm investigations.
The rate of hydrolysis of fish proteins using the enzymes papain and pancreatin was monitored using the apparatus shown. The pH decreased with the progress of hydrolysis, so alkali in the burette was added as necessary in order for the hydrolysis to proceed at constant pH. The rate of protein hydrolysis was measured as the amount of alkali added. Measurements were taken at constant conditions of temperature and pH for two enzyme concentrations, 1 % and 0.1 %.
State the effect of enzyme concentration on the hydrolysis of proteins.
Sketch on the graph the curve expected if the hydrolysis were performed using papain 0.5 %.
Explain what would happen to fish protein hydrolysis if no alkali were added to the reaction vessel.