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A culture of Spirogyra (an autotrophic alga) is maintained in a water solution containing dissolved carbon dioxide and a source of phosphates but lacking nitrogen compounds. A researcher determines the rates of synthesis of several organic compounds found in the Spirogyra before and after several weeks in the water solution. Which of the following graphs best illustrates a likely result of the experiment?
A culture of Spirogyra (an autotrophic alga) is maintained in a water solution containing dissolved carbon dioxide and a source of phosphates but lacking nitrogen compounds. A researcher determines the rates of synthesis of several organic compounds found in the Spirogyra before and after several weeks in the water solution. Which of the following graphs best illustrates a likely result of the experiment? a. Carbohydrates: same
b. Proteins: decrease
c. Lipids: same
d. Nucleic Acids: decrease
Answer:b) Proteins: decreaseExplanation:Out of all thebiomoleculesrequired for the survival of an organism,proteinsandnucleic acidsare the ones containingNitrogen. Innucleic acids, the building blocks of DNA, nitrogen is present in thenitrogenous bases, which are Adenine, Guanine, Cytosine, Thymine, and Uracil. In the proteins, theamino acidscontain theamine groupor-NH₂which forms thepeptide bond (-NH-CO-)with acarboxylic groupor-COOHof the next amino acid. As the culture ofSpirogyrais being maintained, there would beno replication of DNA, which would have required nitrogen to synthesize the new DNA strand. But, to synthesize proteins, theRNA synthesiswould require to happen which would also require nitrogen. Moreover, the formation of proteins after the translation of themRNAwould have also required Nitrogen. Thus,protein level in the cells would decrease....