Problem:

Question 1: What was the purpose of adding methotrexate to the cells expressing a genetically-engineered Dihydrofolate Reductase enzyme in the mitochondrion-targeting experiment? What did the experiment demonstrate in terms of the location of the site(s) of translocation of proteins into mitochondria?

Question 2: What is the entire series of events through a three-neuron loop, including the steps of synaptic transmission between neurons 1 and 2 the step of the action potential that occur in neuron 2, the propagation of the action potential down the axon of neuron 2, and the steps of synaptic transmission that occur etween neuron 2 and 3?

Could someone help to explain the answer of these questions.