On page 105 of The Great Gatsby, the third page of chapter six, in the First Scribner Paperback Fiction Edition 1995, a passage like the one you need begins with "But his heart was in a constant, turbulent riot...." and ends with "...on the day that Dan Cody's yacht dropped anchor in the shallows along shore."
The passage characterizes Gatsby, furthers the theme of illusion and reality, and begins a segment of history that concerns how Gatsby came to be Gatsby, persona and all.
Gatsby is revealed to be restless, to possess a furtive and creative mind, to be a "dreamer," so to speak, and to believe that he was destined for greatness.
The passage establishes Gatsby's naivete, his wish or hope or belief that "the rock of the world was founded securely on a fairy's wing."
The passage also begins the background of Gatsby's experiences with the millionaire Dan Cody and his yacht.
On page 89 of the Scribner edition a major shift in plot occurs that also develops 2 characters. This is about the middle of chapter 5. Nick had been outside of his house, while Daisy and Gatsby were getting reaquainted inside his home.
The passage would start with, "I went in - after making every possible noise..." and end around, "My house looks well doesn't it?"
This is a twist in the plot because we now see Daisy and gatsby together as a couple from this point on out, although an adulterous couple.
The passage where Nick and Gatsby travel to the city in chapter 5 reveals Gatsby's character to Nick and the reader and several themes and motifs, namely those related to Gatsby as both a fraud and a Bryonic Hero (a sensitive with a mysterious past who has been injured by love).
Here's Nick narration:
I had talked with him perhaps half a dozen times in the past month and found, to my disappointment, that he had little to say: So my first impression, that he was a person of some undefined consequence, had gradually faded and he had become simply the proprietor of an elaborate road-house next door.
And then came that disconcerting ride. We hadn’t reached West Egg village before Gatsby began leaving his elegant sentences unfinished and slapping himself indecisively on the knee of his caramel-colored suit.
“Look here, old sport,” he broke out surprisingly. “What’s your opinion of me, anyhow?” A little overwhelmed, I began the generalized evasions which that question deserves.
“Well, I’m going to tell you something about my life,” he interrupted. “I don’t want you to get a wrong idea of me from all these stories you hear.”
So he was aware of the bizarre accusations that flavored conversation in his halls.
“I’ll tell you God’s truth.” His right hand suddenly ordered divine retribution to stand by. “I am the son of some wealthy people in the Middle West—all dead now. I was brought up in America but educated at Oxford, because all my ancestors have been educated there for many years. It is a family tradition.”
He looked at me sideways—and I knew why Jordan Baker had believed he was lying. He hurried the phrase “educated at Oxford,” or swallowed it, or choked on it, as though it had bothered him before. And with this doubt, his whole statement fell to pieces, and I wondered if there wasn’t something a little sinister about him, after all.
“What part of the Middle West?” I inquired casually.
Last time I checked San Francisco was not the Midwest. So, Gatsby is obviously obscuring his past to protect his identity and further the mystery surrounding his origins.