Question 1:
Dinitrophenol (DNP) was used in the manufacture of munitions during World War II. In the 1930s it was used as a weight loss drug. Use of DNP in the US cannot be regulated by the Food and Drug Administration (FDA) because DNP is considered a dietary supplement. Attempts to ban the drug in the UK following the death of four users in 2015 failed in Parliament.
DNP is a small molecule that is soluble in the mitochondrial inner membrane. The hydroxyl group reversible dissociates (“bumps off”) a proton.
1. Predict the effect of DNP on the electrochemical gradient across the inner mitochondrial membrane.
2. Based on your knowledge of metabolism and cellular respiration, explain how DNP can be used to reduce weight. Think in terms of the overall affect of DNP on metabolism.

Question 2:
A student performed an experiment to investigate seed germination in a plant species. Four groups of 50 seeds each were treated under different conditions as shown in the table. The initial mass of each group of seeds was measured. After 7 days of treatment, each sample was dried, and the final mass determined. Note that the seeds were planted in an open container.
                                    Group I       Group II       Group III       Group IV
Light                               +                   -                   -                     -
Water                             +                   -                  +                     -
Initial mass (g)              10.1                9.9             10.0                9.8
Final Mass (g)              15.0                9.8               5.3                  9.8

1. Based on your understanding of photosynthesis, identify which treatment group germinated and explain your reasoning based on information in the data table.
2. Explain the changes in mass for treatment Groups I and III in terms of both photosynthesis and cellular respiration. In other words, why did I show an increase in mass, and III a decrease in mass?
3. In a second series of experiments, the procedure was repeated but in the presence of a chemical that blocks electron transport. Predict the changes in final mass for Group I under the new conditions and justify the reasoning for your prediction.

Question 3:
Predict one effect of increases in atmospheric CO2 levels on plant growth in an ecosystem of your choice and justify your prediction. Be sure to take into account that plants undergo both photosynthesis and cellular respiration.

Question 4:
In terms of energy and sugar, explain by creating a simple diagram with annotation how the processes of photosynthesis and cellular respiration are interdependent, with complementary metabolic processes. Your diagram must also include a “little twist” that makes it unique and different from any other diagram reflecting this interdependency.

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Question 1:

a) Oxidation of nutrients like fats, sugars and proteins in our body leads to the production of electrons that passes through the electron transport chain (ETC) and generate energy in the form of ATP. In oxidative phosphorylation, the flow of electrons from NADH and FADH2 to oxygen results in the pumping of protons from the mitochondrial matrix to the inner membrane space. This gradient of H+ can produce ATP by flowing through ATP synthetase in the mitochondrial inner membrane. Dinitrophenol (DNP) is an uncoupler of oxidative phosphorylation with an ability to separate the flow of electrons, disrupts the proton pump gradient reducing ATP synthesis. Therefore, uncoupling the electron transport chain leads to decreased production of ATP....

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