First of all, the maxim is in fact 250 words, or 1800 characters. Cheers!
Second, I think you need to shorten the list of the things you learned, like,
we are addressing the contentious issues of global warming, stem cell research, bioengineered foods, cloning, and nuclear power.
Two or three of the examples will suffice.
I have never before considered the cost and consequences of the energy we consume, prescription drugs we take, foods we eat, and potable water we drink.
No need to list all of them. One, if well developed, is enough.
And there are points on which you need incorporate in to a coherent whole.
We read texts to increase our scientific literacy and analyze conflicting data.
This is a methodology.
Instead of learning the black and white facts of science, I am expanding my vision into the gray areas.
This could be a aim..If you elaborate a bit more.
the cost and consequences of the energy we consume, prescription drugs we take, foods we eat, and potable water we drink
These are the topics. Choose one.
Each topic introduces new perspectives and sparks new thoughts, challenging me to broaden my understanding of its controversy and implications for society. We delve into and beyond the superficial conversation of each topic and explore the complexity of the issues that will soon require action, encouraging me to reflect on science's monumental influence on our lives.
This is what it make you feel.
See? You have a complete scientific exploration thing(sry, my English is awkward) here, but they are scattered. What you need to do is choose one of the topics and train everything down.
I went to your stage before: if the experience is very inspiring, I would spend a lot of time grasping the delicate feelings and the changes it brings to me, making the essay very abstract. But an essay that best express your idea may not be the essay that other people like to read.