While zinc (Zn[superscript 2+]) is a vital ion for cell function and human health, we are still learning about how Zn[superscript 2+] concentration and localization is regulated and the role that Zn[superscript 2+] fluctuations may play in regulating cell signaling and cell fate. Here, we use fluorescent tools to study the interaction between Zn[superscript 2+] and cell signaling pathways that play a role in cell growth and proliferation. Importantly, we use small, non-toxic Zn[superscript 2+] concentrations to ensure that our Zn[superscript 2+] changes are closer to what cells would experience in the body and not stress-inducing. We demonstrate that both ERK and Akt dependent signaling is activated by Zn[superscript 2+] and that Zn[superscript 2+] -dependent ERK signaling is driven by Ras activation, contradicting one of the major hypotheses in the field. Our sensors shed light on how cells respond to an important micronutrient in real time. We also design and use fluorescent Zn[superscript 2+] sensors to measure vesicular Zn[superscript 2+] concentrations in insulin-producing and prostate cells, two secretory cell types where Zn[superscript 2+] dis-regulation has been linked with disease. We improved sensor design for vesicular targeting by using cargo proteins as localization domains and taking into account vesicular pH and the role that it plays on fluorescent protein signal. We also demonstrate that the pancreatic [beta]-cell line MIN6 contains much higher vesicular Zn[superscript 2+] than the prostate cancer cell line LnCaP, on a single-cell level. Finally, in an effort to incorporate more active learning in the college classroom, I present work from two fellow graduate students and myself on a case study exercise for the undergraduate metabolism classroom. This case study has been presented in six recitation sections with positive student feedback and is accepted for publication at the National Center for Case Study Teaching in Science. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]