worksheet of biochemistry

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, a
ows etc) of the figure MUST be RED (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!
· The overall presentation must be neat and will be considered in marking! (2 marks)
2) Function of photosynthetic pigments
a) Why is β-carotene red/orange? i) describe its spectroscopic properties and ii) name the structural feature that is responsible for abso
ing visible light (less than 50 words total) (1.0 mark)
) Consider the various photosynthetic pigments that are present in plants and that farmers feed green grass to chickens to enhance the yellow appearance of egg yolks.
i) Which molecule contributes to the appearance of egg yolk and ii) name one function that this molecule has in animals? (less than 50 words total) (1.0 mark)
3) Properties of tetrapy
ole molecules
In your practical you used TLC to analyse chlorophyll extract to observe changes to the photosynthetic pigments after they were subjected to cation exchange chromatography.
Hypothesise what would happen if you did the same experiment using a heme solution.
a) Similar to chlorophyll pigments, would you expect the cation exchange chromatography to be able to remove the iron atom from the heme group? (1 mark)
) Compare the properties of heme bound to Fe2+ and heme lacking Fe2+. i) How would these molecules migrate in the TLC relative to each other? ii) Explain your answer (1 mark)
c) During the SLE22 practical, a student put both the chlorophyll and pheophytin solutions under a fluorescent light source. They noticed that both solutions florescenced to produce an orange colour. From this observation, they were then able to deduce which part of the chlorophyll molecule was responsible for the absorption of the light photon and the source of the electrons from the special pair. Explain the student’s observation and conclusion.
In your answer i) describe the mechanism of chlorophyll fluorescence and ii) describe which part of the chlorophyll molecule is responsible for the absorption of light and source of electrons. In your answers link the experimental observation with the conclusion. (must be less than 100 words total)
(1 mark)
4. Mechanism of Atrazine
Research how the he
icide Atrazine interferes with the coupled photosystems of plants.
i) name the molecular target that is bound by Atrazine, ii) explain the immediate effect that Atrazine has on the functioning of the coupled photosystem, iii) name the major products of the photosynthesis light reactions which are not produced any more due to Antrazine action and iv) give two reasons why plants die when treated with Atrazine.
(no more than total of 10 lines total, 12 pt font)
(2.0 marks)
5. Importance of photosynthesis for life on this earth
Reflect upon the importance...