AP Biology Unit 6 Practice Test: Gene Expression and Regulation
Practise AP Biology Unit 6 with tests on DNA replication, transcription, translation, operon regulation, mutations, and biotechnology. AP-style questions explained.
What Unit 6 Covers in AP Biology
Unit 6 connects the structure of DNA to the production of functional proteins and examines the regulatory systems that control when and how genes are expressed. This unit is central to AP Biology FRQs, which frequently ask students to trace the molecular steps from gene to protein and explain how mutations or regulatory changes affect biological outcomes.
Core Topics in Unit 6
DNA Replication
Semi-conservative replication uses helicase, primase, DNA polymerase (III and I), and ligase to accurately copy the genome. AP questions test your understanding of leading and lagging strand synthesis, Okazaki fragments, and the role of each enzyme.
Transcription and RNA Processing
Transcription in eukaryotes involves RNA polymerase transcribing a DNA template into pre-mRNA. Post-transcriptional processing — 5' cap, poly-A tail, and splicing of introns — produces mature mRNA ready for translation. Know how these steps differ between prokaryotes and eukaryotes.
Translation and Post-Translational Modifications
Ribosomes translate mRNA codons into amino acid sequences using tRNA. AP Biology tests codon-anticodon pairing, the role of start/stop codons, and how post-translational modifications (phosphorylation, glycosylation, cleavage) affect protein function.
Gene Regulation in Prokaryotes — The Operon Model
The lac operon and trp operon illustrate inducible and repressible gene regulation. AP FRQs frequently present operon diagrams and ask you to predict gene expression under varying substrate or product conditions.
Gene Regulation in Eukaryotes
Eukaryotic gene regulation involves transcription factors, enhancers, silencers, epigenetic modifications (methylation, histone acetylation), and RNA interference (siRNA, miRNA). AP Biology tests conceptual understanding of how these mechanisms turn genes on or off.
Mutations and Their Effects
Point mutations (missense, nonsense, silent, frameshift) have predictable consequences on protein structure and function. AP FRQs ask you to trace a mutation from DNA sequence to protein outcome.
Biotechnology Techniques
Key techniques include PCR, gel electrophoresis, restriction enzyme digestion, CRISPR-Cas9, and recombinant DNA technology. AP Biology tests conceptual application, not laboratory procedure memorisation.
AP Science Practice Skills for Unit 6
- Data analysis: Interpreting gel electrophoresis results and gene expression data
- Scientific argumentation: Explaining how a mutation in a regulatory sequence alters protein production
- Tracing molecular pathways: Following gene expression from DNA replication through post-translational modification