Passage
Malaria is caused by the parasite Plasmodium falciparum and is transmitted through a female mosquito bite. Although there are antimalarial treatments available, P. falciparum has become resistant to many of these drugs. P. falciparum cells contain a respiratory organelle called the apicoplast that is necessary for the parasite's survival but is not found in humans. Therefore, a new drug that targets this organelle could be useful in the treatment of malaria.A portion of the apicoplast protein ferredoxin (PfFd) is shown in Figure 1, with certain amino acid residues labeled. In the apicoplast, ferredoxin NADP⁺ reductase (PfFNR) interacts electrostatically with PfFd and catalyzes an electron transfer reaction. A compound that selectively inhibits this interaction could be a beneficial antimalarial agent.
Figure 1 Structure of a portion of PfFdChalcone (Compound 3) is a compound that interacts with PfFd and exhibits antimalarial properties. A series of chalcone derivatives (Compounds 4-8) were synthesized via the aldol condensation shown in Scheme 1, where nucleophilic addition of Compound 1 to Compound 2 is followed by elimination to yield α,β-unsaturated carbonyl molecules, Compounds 3-8.
Scheme 1An inhibition assay was performed to compare chalcone (Compound 3) and its derivatives by determining the extent to which these compounds inhibited electron transfer between PfFNR and PfFd (Table 1) .Table 1 Inhibition of electron transfer assay results
Adapted from H. Suwito et al. "Design and synthesis of chalcone derivatives as inhibitors of the ferredoxin - ferredoxin-NADP+ reductase interaction of Plasmodium falciparum: pursuing new antimalarial agents." Molecules. ©2014 MDPI.
-Based on the data in Table 1, what effect do the chalcone derivative substituents have on the percent inhibition relative to chalcone?

Question

Passage
Malaria is caused by the parasite Plasmodium falciparum and is transmitted through a female mosquito bite. Although there are antimalarial treatments available, P. falciparum has become resistant to many of these drugs. P. falciparum cells contain a respiratory organelle called the apicoplast that is necessary for the parasite's survival but is not found in humans. Therefore, a new drug that targets this organelle could be useful in the treatment of malaria.A portion of the apicoplast protein ferredoxin (PfFd) is shown in Figure 1, with certain amino acid residues labeled. In the apicoplast, ferredoxin NADP⁺ reductase (PfFNR) interacts electrostatically with PfFd and catalyzes an electron transfer reaction. A compound that selectively inhibits this interaction could be a beneficial antimalarial agent.

Figure 1 Structure of a portion of PfFdChalcone (Compound 3) is a compound that interacts with PfFd and exhibits antimalarial properties. A series of chalcone derivatives (Compounds 4-8) were synthesized via the aldol condensation shown in Scheme 1, where nucleophilic addition of Compound 1 to Compound 2 is followed by elimination to yield α,β-unsaturated carbonyl molecules, Compounds 3-8.

Scheme 1An inhibition assay was performed to compare chalcone (Compound 3) and its derivatives by determining the extent to which these compounds inhibited electron transfer between PfFNR and PfFd (Table 1) .Table 1 Inhibition of electron transfer assay results

Adapted from H. Suwito et al. "Design and synthesis of chalcone derivatives as inhibitors of the ferredoxin - ferredoxin-NADP+ reductase interaction of Plasmodium falciparum: pursuing new antimalarial agents." Molecules. ©2014 MDPI.
-Based on the data in Table 1, what effect do the chalcone derivative substituents have on the percent inhibition relative to chalcone?

Quizplus · Accepted Answer

11ecba2d_12a4_3a4a_a3bf_85844bff1c3d_MD0008_00 The chalcone derivatives were synthesized in an effort to improve the antimalarial activity of chalcone. The passage states that a compound that could selectively inhibit the interaction between PfFNR and PfFd could be a beneficial antimalarial agent. Chalcone (Compound 3) and its derivatives (Compounds 4-7) were tested in an assay to determine the effect the compounds had on the electron transfer between PfFNR and PfFd. Table 1 indicates that chalcone inhibits 23.06% of the interaction between PfFNR and PfFd. Each chalcone derivative has a different impact on the electron transfer reaction. Compounds 4-7 each have only one substituent (either NH₂ or OCH₃), and these compounds are weaker inhibitors than chalcone because their percent inhibition values are lower than 23.06%. Compound 8 has both NH₂ and OCH₃ substituents. The percent inhibition for this derivative is 51%, indicating that Compound 8 inhibits the interaction between PfFNR and PfFd to a greater extent than does chalcone. Therefore, both the NH₂ and OCH₃ substituents are necessary to increase the percent inhibition relative to chalcone. (Choices A, B, and D) The chalcone derivative substituents each have an impact on the percent inhibition compared to chalcone. Alone, NH₂ and OCH₃ have a negative effect because the percent inhibition for Compounds 4-7 is lower than that of chalcone (23.06%). The data in Table 1 indicate that both substituents are needed to increase the percent inhibition relative to chalcone. Educational objective: Structural modifications to biologically active molecules are performed to determine whether the biological activity of the molecule can be increased. To determine the effect of the structural modifications, the activity of each modified molecule should be compared to that of the original molecule.

Passage Malaria Is Caused by the Parasite Plasmodium Falciparum and Is