CHARLOTTE, N.C. -- First lady Michelle Obama headlined the opening day of the Democratic National Convention on Tuesday with an emotion-charged speech designed to build enthusiasm among women and minorities, whose votes are critical to re-electing her husband."We must work like never before," she told the convention, urging them to help President Barack Obama defeat Republican presidential nominee Mitt Romney. She asked supporters to rally to her husband's side as they did in first helping him win the White House four years ago."And we must once again come together and stand together for the man we can trust to keep moving this great country forward, my husband, our president, Barack Obama," she told the cheering delegates.In a largely personal tale, the first lady tried to connect her husband to working Americans, talking about his humble beginnings, his decision to forgo a high-paying career in favor of community work and public service, and about his life as a loving husband and father. She recounted her husband's modest upbringing by a single mother and his grandparents and later their life as a young married couple who had student loan bills higher than their mortgage."Today, after so many struggles and triumphs and moments that have tested my husband in ways I never could have imagined, I have seen firsthand that being president doesn't change who you are -- no, no, it reveals who you are," she said to a thunderous ovation.The first lady -- lauded earlier by her brother, Craig Robinson, and her sister-in-law, Maya Soetoro-Ng -- told the thousands at Time Warner Cable Arena that Obama had worked tirelessly to make the economy more stable, ease college students loans and improve health care."He believes that when you've worked hard, and done well, and walked through that doorway of opportunity ... you do not slam it shut behind you. ... No, you reach back, and you give other folks the same chances that helped you succeed," she said.The audience erupted into their longest, loudest cheers of the night when Michelle Obama came to the stage to the tune Stevie Wonder's Signed, Sealed, Delivered, I'm Yours.They waved thousands of blue signs: "We Love Michelle" and interrupted her from time to time with chants of "Four more years!"Her appeal capped a day that included the adoption of a party platform that for the first time embraces gay marriage but dropped the party's earlier support for Jerusalem's status as Israel's capital. Republicans quickly pounced on the omission, with House Majority Leader Eric Cantor of Virginia saying the administration was distancing itself from Israel.The evening saw a diverse parade of speakers that included San Antonio Mayor Julian Castro, the first Latino keynote speaker in convention history, as well as the chairman of the Congressional Hispanic Caucus, the first woman to reach the rank of Army three-star general, black members of Congress, and the convention chairman, Los Angeles Mayor Antonio Villaraigosa. Together, they served as a not-so-subtle nod to the changing demographics of the nation.More than 300 miles away, Obama used the campus of a historically black university in Norfolk, Va., as his last campaign stop before he heads to Charlotte on Wednesday for the final two days of the convention."We've come too far to turn back now," Obama said at Norfolk State University. "We've created a lot of jobs. But we've got more jobs to create."Obama said he planned to watch the first lady's speech at the White House, with their two daughters, and would try not to let the girls see him cry, as her speeches make him "misty."