The above answer is thorough. I will also add this: Keep in mind that in order to create Scope and Sequence, the designer of the curriculum must have a clear assessment established first. A summative assessment at the end of a quarter (midterm for example) or a Final Exam summative assessment, which evaluates the skills the students have accrued over the course of the instruction, has to be designed. That is to say, what do you want the students to know?
This will then inform the teacher how to build the curriculum, what skills are necessary, what mini-tasks (lessons) are necessary to directly teach those skills (Direct Instruction), what Formative Assessments to design in the curriculum to guage the success or gaps of their students and determine what needs to be taught or re-taught.
So the "scaffolding" (backward design) is crucial for a strongly developed curriculum, along with embedding the literacy skills of the Common Core State Standards (adopted by 45 states and the district).
This is where the Literacy Design Collaborative (LDC) becomes useful for teachers who are in the midst of designing their curriculum.