Question 1. Produce a figure with an appropriate figure legend of your TLC analysis of photosynthetic pigments that could be published in a scientific journal.
- Indicate all relevant information, e.g.origin, solvent front
- identify and label β-carotene, chlorophyll a, chlorophyll b, pheophytin a and pheophytin b only.
- indicate the samples spotted in the different lanes.
The colour of all labelling (words, numbers and lines, arrows etc) of the figure MUST be BLACK (you will receive 0 marks for question 1 in case that you use a different colour).
- Provide a figure legend, which concisely describes the graph that is shown and the experiment that underlies the measurements. A figure legend gives some experimental information to provide context but does not reproduce the entire procedure in detail. It also defines any terms or symbols or describes equation terms to allow the reader to understand the figure by itself. A figure legend should not contain any interpretation of the results!

Question 2a. By describing its chemical properties, explain why β-carotene ran near the solvent front? (In your answer describe the principle behind the Thin Layer Chromatography used in the practical.)

Question 2b) Describe the biological functions of β-carotene.

Question 3a.The following questions refer to changes of chlorophyll B molecules following treatment with the Dowex 50W X8 strong cation exchange column.i) Provide the correct name for the molecule exiting the column, ii) describe the change in colour that was observed when the molecule passed through the column, iii) describe the likely spectroscopic properties(absorbance properties in the visible range spectrum) of the molecules after they passed through the ion exchange columeand iv) name the structural feature of the molecule that facilitates the absorption of visible light.

Question 3b. What chemical forces acted on the chlorophyll pigments when the sample was passed through the strong cation exchange (Dowex 50W X8) resin? What does this tell you about the nature of the bonds holding the magnesium ion in place within the tetrapyrole ring?

Question 4. In your work as a biochemist, you synthesise a potential hypothetical herbicide. This herbicide is a weak hydrophobic acid that works as an un-coupler by dissipating the proton gradient across the thylakoid membrane.

a) Explain the effect that this herbicide would have on the i) light and ii) dark reactions of photosynthesis. Provide a description of which enzyme(s) and the reactions that they catalyze that would be affected in dark reactions.

b) Would you expect that this herbicide would be toxic to animals? Justify your answer (must be less than 100 words)

Question 5. Importance of photosynthesis for life on this earth

You are assigned to a team of biologists who are philosophising about building a sustainable colony of Mars. Reflecting upon the importance of photosynthesis for life on earth, present an argument as to why it would be import to ultimately sustain a colony using photosynthetic organisms such as plants. (no more than maximum of 10 lines)

Attachment:- Practical Worksheet.rar