Live online USABO Semifinal prep. The curriculum has 9 units, from Gene Expression Regulation, Epigenetics, & Non-Coding RNAs to Experimental Design, Data Analysis, & Practical Lab Reasoning.
The premier national biology competition in the US, serving as the selection mechanism for the USA Biological Olympiad Team.
Opens with the 50-minute Open Exam (multiple-choice), progressing to the Semifinal Exam (part A/B/C short answer and essay), and the National Finals (lab practicals & theory). Covers cell biology, genetics, ecology, and biosystematics.
Skillzy Young Scholars teaches USABO Semifinal in live online classes with vetted mentors who have completed 100 hours of training. The curriculum is organised into 9 units, with worksheets, quizzes, timed practice and mock exams. Progress is tracked in the LMS and shared with parents in a monthly report.
Classes follow these units. Every student starts with a level check, and the order and pace adapt to your child. Units that go beyond the exam's core topics are stretch material.
- Target Audience
- High school students in Grades 9–12 who qualify as USABO Semifinalists (~top 10% of Open Exam test-takers nationwide).
- Exam Structure & Format
- 120-minute multi-part comprehensive examination:
- 1. Part A: High-speed multiple-choice questions (1 point each).
- 2. Part B: Complex multiple-choice, multi-select, matching, and diagram identification questions (higher point values).
- 3. Part C: Short-answer, computational, and data-interpretation free-response questions.
- National Finals Training Camp
- The top 20 scorers on the Semifinal Exam nationwide earn selection as USABO National Finalists, attending an intensive 2-week residential training camp at a host university featuring rigorous theoretical exams and hands-on laboratory practicals (Cell/Mol Bio, Biochemistry, Botany, Physiology, and Systematics) to select the 4-member USA Team for the International Biology Olympiad (IBO).
What the program focuses on
- Advanced Molecular Biology & Epigenetics (eukaryotic gene regulation, operons, chromatin remodeling, non-coding RNAs, and biotechnology like PCR, CRISPR, NGS, and cloning)
- Advanced Biochemistry & Energetics (integrated metabolic pathways, enzyme kinetics Km/Vmax, allosteric control, and bioenergetics thermodynamics)
- Advanced Genetics & Mapping (3-point testcross mapping, non-disjunction, quantitative trait loci, and complex genetic disorders)
- Advanced Ecology & Evolutionary Systematics (coevolutionary arms races, phylogenetic tree construction, cladistics, and quantitative community models)
- Comparative Phyla Anatomy & Physiology (metazoan body plans, circulatory/excretory evolution across phyla, and physiological adaptations)
- Experimental Design & Data Interpretation (interpreting gel electrophoresis, blot assays, mass spectrometry, and statistical hypothesis testing)
Units
1 Gene Expression Regulation, Epigenetics, & Non-Coding RNAs
Students will learn to:
- Master Prokaryotic Operon Control: Analyze lac, trp, and arabinose operons; differentiate negative/positive regulation, attenuation, and catabolite repression (cAMP − CAP).
- Analyze Eukaryotic Transcriptional Regulation: Detail promoter elements (TATA box, enhancers, silencers), transcription factors, mediator complexes, and DNA-binding motifs (zinc finger, leucine zipper, helix-turn-helix).
- Master Epigenetic Mechanisms: Evaluate DNA methylation (CpG islands), histone post-translational modifications (acetylation via HATs/HDACs, methylation, phosphorylation), and chromatin remodeling complexes (SWI/SNF).
- Analyze Post-Transcriptional & Translational Control: Master alternative RNA splicing, mRNA stability, microRNAs (miRNA), small interfering RNAs (siRNA), and RNA interference (RNAi) pathways.
USABO Alignment - Molecular Biology Subfield. Semifinal Part B and C questions heavily test epigenetic modification experiments, RNAi knock-down assays, and eukaryotic transcription factor binding curves.
Learning activities:
- Prokaryotic operon mutation phenotype analysis problem sets
- Histone modification and chromatin accessibility assay workshops
- miRNA vs. siRNA regulatory pathway mapping drills
What this means for your child. Your child will master advanced eukaryotic gene regulation and epigenetics, analyzing transcription factors, histone modifications, and RNAi pathways.
2 Advanced Biotechnology Techniques & Molecular Assays
Students will learn to:
- Master Polymerase Chain Reaction (PCR) & Editing: Detail quantitative real-time PCR (RT − qPCR), primer design rules, site-directed mutagenesis, and CRISPR − Cas9 gRNA-mediated gene editing mechanisms.
- Analyze DNA Sequencing Technologies: Compare Sanger dideoxy sequencing with Next-Generation Sequencing (NGS - Illumina bridge amplification, ion torrent, nanopore).
- Analyze Molecular Cloning & Vector Systems: Design recombinant plasmids using restriction enzymes, Gibson assembly, selectable markers (ampicillin, lacZ blue/white screening), and expression vectors.
- Interpret Molecular Blotting & Assays: Analyze Western blots (proteins), Northern blots (RNA), Southern blots (DNA), EMSA (gel shift assays), Co-IP, ChIP-seq, and Flow Cytometry/FACS data.
USABO Alignment - Biotechnology Subfield. Data interpretation questions on Part C of the Semifinal Exam demand rapid, accurate reading of Western blots, ChIP-seq binding profiles, and FACS scatter plots.
Learning activities:
- Western blot and ChIP-seq experimental data analysis workshops
- Plasmid map restriction digestion and Gibson assembly design labs
- Sanger sequencing chromatogram and NGS read interpretation drills
What this means for your child. Your child will learn advanced biotechnology protocols, interpreting PCR, CRISPR, Sanger/NGS sequencing, and Western/ChIP-seq assays.
3 Advanced Recombination Mapping & Quantitative Genetics
Students will learn to:
- Execute 3-Point Testcross Mapping: Calculate recombination frequencies, construct chromosome linkage maps, determine gene order, and compute coefficient of coincidence and interference ( I = 1 − C).
- Analyze Non-Disjunction & Chromosomal Aberrations: Evaluate meiotic I vs. II non-disjunction events, translocations (Robertsonian), inversions (paracentric vs. pericentric), deletions, and duplications.
- Master Quantitative Trait Loci (QTL) & Population Math: Calculate narrow-sense (h = VA/VP) and 2 2 broad-sense (H = VG/VP) heritability, response to selection (R = h S), and QTL mapping principles.
- Evaluate Human Genetic Disorders: Analyze complex pedigrees incorporating incomplete penetrance, variable expressivity, genomic imprinting (Prader-Willi / Angelman), and mitochondrial inheritance.
USABO Alignment - Genetics Subfield. 3-point testcross mapping and heritability calculations are high-value quantitative problem types on Semifinal free-response sections.
Learning activities:
- 3-point testcross linkage mapping and interference calculation problem sets
- Quantitative genetics heritability (h ) and selection response (R) calculation labs
- Genomic imprinting and mitochondrial pedigree diagnostic workshops
What this means for your child. Your child will master advanced genetics, executing 3-point recombination maps, calculating heritability, and diagnosing complex human disorders.
4 Advanced Enzyme Kinetics & Allosteric Thermodynamics
Students will learn to:
- Derive Michaelis-Menten Kinetics: Derive v0 = Kmax +[S] ; define Km, Vmax, turnover number (kcat), and m catalytic efficiency (kcat/Km).
- Analyze Lineweaver-Burk Double-Reciprocal Plots: Evaluate linear transformations ( 1 K 1 1 v0 = Vm [S] + V ) to identify inhibition types: Competitive, Uncompetitive, and max max Non-competitive/Mixed.
- Analyze Allosteric Enzymes & Cooperativity: Model cooperativity using the Hill equation (h > 1), MWC concerted model vs. KNF sequential model, and allosteric effectors (e.g., 2, 3 − BPG, ATP/AMP regulation of phosphofructokinase-1). '
- Apply Bioenergetics Thermodynamics: Calculate standard free energy changes (∆G ) and actual free ' energy changes (∆G = ∆G + RT ln Q), coupling exergonic ATP hydrolysis to endergonic reactions.
USABO Alignment - Biochemistry Subfield. Enzyme kinetics graphs (Michaelis-Menten and Lineweaver-Burk) and thermodynamic coupling calculations appear on almost every Semifinal Exam.
Learning activities:
- Lineweaver-Burk plot transformation and inhibitor identification labs
- Hill coefficient and allosteric cooperativity analysis workshops
- Thermodynamic coupling (∆G) energy calculation problem sets
What this means for your child. Your child will master enzyme kinetics and bioenergetics, calculating Michaelis-Menten parameters, Lineweaver-Burk plots, and ∆G thermodynamic changes.
5 Integrated Metabolic Pathways & Regulation
Students will learn to:
- Detail Integrated Carbohydrate Metabolism: Trace Glycolysis, Gluconeogenesis, Glycogenolysis, Glycogenesis, and the Pentose Phosphate Pathway, analyzing reciprocal hormonal control (Insulin vs. Glucagon/Epinephrine).
- Detail Cellular Respiration & Photosynthesis Thermodynamics: Analyze the Citric Acid Cycle, Electron Transport Chain (ComplexI − IV), proton-motive force (∆p), ATP Synthase rotational mechanics, and C3/C4/CAM Calvin cycle energetics.
- Detail Lipid & Amino Acid Metabolism: Trace β-oxidation of saturated/unsaturated fatty acids, fatty acid synthesis, urea cycle, and ketogenic vs. glucogenic amino acid breakdown pathways.
- Examine Metabolic Integration Across Tissues: Model metabolic shifts during well-fed, fasting, and prolonged starvation states across liver, skeletal muscle, adipose tissue, and brain.
USABO Alignment - Biochemistry Subfield. Complex multi-pathway integration questions test metabolic regulation under physiological stress (e.g., exercise, starvation, diabetes).
Learning activities:
- Reciprocal hormonal metabolic control mapping workshops
- β-oxidation and ATP yield stoichiometry calculation problem sets
- Inter-organ metabolic flow mapping during starvation and exercise labs
What this means for your child. Your child will learn integrated metabolism, detailing carbohydrate, lipid, and amino acid pathways across tissue types.
6 Quantitative Ecology, Coevolution, & Community Models
Students will learn to:
- Apply Quantitative Community Models: Calculate Shannon-Wiener Diversity Index (H' =− ∑ pi ln pi), z Simpson's Index, and species-area relationships (S = cA ).
- Model Interspecific Competition & Predation: Formulate Lotka-Volterra competition equations ( dN1 K1−N1−αN2 dt = r1N1 K1 ) and predator-prey oscillation equations.
- Analyze Evolutionary Game Theory: Model Evolutionary Stable Strategies (ESS) using Hawk-Dove payoff matrices and frequency-dependent selection.
- Analyze Coevolutionary Dynamics: Study mutualistic coevolution, Red Queen hypothesis host-parasite dynamics, and Müllerian vs. Batesian mimicry rings.
USABO Alignment - Ecology Subfield. Lotka-Volterra phase-plane graphs, Shannon diversity math, and game theory matrices distinguish top Semifinal scorers.
Learning activities:
- Lotka-Volterra competition phase-plane graph analysis workshops
- Shannon-Wiener and Simpson diversity index calculation labs
- Hawk-Dove game theory payoff matrix problem-solving drills
What this means for your child. Your child will master quantitative ecology, applying Lotka-Volterra equations, diversity indices, and evolutionary game theory.
7 Cladistics, Phylogenetics, & Comparative Systematics
Students will learn to:
- Construct Cladograms & Phylogenetic Trees: Build character matrices, differentiate apomorphies, synapomorphies, plesiomorphic traits, and monophyletic, paraphyletic, and polyphyletic taxa.
- Apply Tree-Building Algorithms: Apply Maximum Parsimony (Occam's razor principle minimizing evolutionary steps), Maximum Likelihood, and Neighbor-Joining methods.
● Analyze Molecular Clocks & Sequence Alignment: Calculate evolutionary divergence times using. neutral mutation rates, PAM/BLOSUM substitution matrices, and sequence alignments. ● Master Comparative Metazoan Phylogeny: Trace animal body plan evolution: diploblastic vs. triploblastic, protostome (ecdysozoa vs. lophotrochozoa) vs. deuterostome development, coelom types, and segmentation. USABO Alignment - Biosystematics Subfield Constructing maximum parsimony trees from character/DNA sequence matrices is a staple of USABO Semifinal and National Finals practical exams.
Learning activities:
- Maximum parsimony cladogram construction from character matrices workshops
- DNA sequence alignment and molecular clock divergence calculation labs
- Metazoan body plan evolutionary transition mapping exercises
What this means for your child. Your child will learn cladistics and systematics, building maximum parsimony trees and analyzing comparative animal phyla evolution.
8 Comparative Animal Phyla Anatomy & Physiology
Students will learn to:
- Compare Circulation & Gas Exchange Across Phyla: Contrast open vs. closed circulatory systems (Arthropoda, Mollusca, Annelida, Vertebrata); compare skin, book lungs, tracheal systems, countercurrent gill exchange, and vertebrate 2/3/4-chambered hearts.
- Compare Osmoregulation & Excretion Across Phyla: Analyze contractile vacuoles, protonephridia (flame cells), metanephridia, Malpighian tubules, and vertebrate nephrons; contrast ammonia, urea, and uric acid nitrogenous waste excretion energetics.
- Compare Nervous & Sensory Systems Across Phyla: Trace nerve nets (Cnidaria), ladder-like systems (Platyhelminthes), ventral nerve cords with ganglia (Annelida/Arthropoda), and dorsal hollow nerve cords (Chordata).
- Analyze Plant Comparative Anatomy & Physiology: Compare non-vascular, seedless vascular, gymnosperm, and angiosperm anatomical structures (xylem/phloem transport via cohesion-tension theory, stomatal regulation via guard cell ion fluxes, and phytohormone signaling: Auxin, Cytokinin, Gibberellin, ABA, Ethylene).
USABO Alignment - Physiology Subfield. Anatomy & Physiology accounts for 25% of all exam points. Semifinal questions demand deep cross-phyla comparisons of organ systems and plant physiological transport.
Learning activities:
- Cross-phyla excretory and circulatory organ system comparison matrix workshops
- Plant xylem/phloem transport and guard cell ion flux mechanism labs
- Comparative animal phyla dissection and anatomical feature identification drills
What this means for your child. Your child will master comparative physiology across animal phyla and plant vascular systems, evaluating evolutionary organ adaptations.
9 Experimental Design, Data Analysis, & Practical Lab Reasoning
Students will learn to:
- Design Rigorous Biological Experiments: Formulate controlled hypotheses, identify independent/dependent variables, establish positive/negative controls, and eliminate confounding variables.
- Apply Biological Biostatistics: Calculate mean, standard error of the mean (SEM = s/ n), 95% confidence intervals, Chi-Square (χ ) goodness-of-fit tests, Student's t-tests, and ANOVA.
- Interpret Experimental Figures & Publications: Analyze multi-panel research paper figures, cell fractionation graphs, enzyme inhibition curves, and electrophysiological patch-clamp traces.
- Prepare for National Finals Practical Exams: Master laboratory techniques: micropipetting accuracy, spectrophotometry (Beer − LambertLaw: A = εcl), protein/DNA gel electrophoresis, dissection technique, and optical microscopy calibration.
USABO Alignment - Experimental & National Finals Preparation. Part C of the Semifinal Exam and all National Finals practical exams test experimental design, statistical hypothesis testing, and laboratory data analysis.
Always check the official exam organizer for the current format, dates and eligibility. We do not guarantee scores or rankings.
Every student begins with a level check so we can see where the gaps are. Private 1:1 students also get a full diagnostic assessment and a personalized roadmap. We teach the concepts behind each question type, practice under timed conditions, and review every wrong answer. We cannot guarantee specific scores, but progress is tracked in monthly reports.