How does Unit 1 connect to the rest of AP Biology?

Unit 1 sets up everything that follows. Cell membranes in Unit 2 are built from phospholipids and proteins. Enzymes in Unit 3 are proteins that catalyze metabolism. DNA replication in Unit 6 depends on nucleotide chemistry. Even ecology in Unit 8 traces matter and energy through carbon, nitrogen, and water cycles. Mastering Unit 1 makes every later unit easier.