OBQ study guide
OBQ · Work through your exam, one topic at a time.
The OBQ is a multiple-choice biology examination organised around seven weighted domains: Cell and Molecular Biology, Genetics and Genomics, Biochemistry and Metabolism, Organismal Biology, Ecology and Evolution, Quantitative Reasoning and Data Analysis, and Experimental Design and Laboratory Methods. The first five domains each carry roughly equal weight, quantitative reasoning matches them, and laboratory methods is the smallest component. The OBQ study guide has 7 sections and about 1,991 words.
01Cell and Molecular Biology: Compartmentalization, Information Flow, and Membrane Dynamics
A candidate must be fluent in the central dogma and its exceptions (reverse transcription, RNA editing, prion-like templating), the endomembrane system and its directional traffic (ER → Golgi → plasma membrane or lysosome; retrograde COPI vs anterograde COPII), cytoskeletal motors (myosin on actin, kinesin toward microtubule plus ends, dynein toward minus ends), and the cell-cycle checkpoints with their cyclin-CDK pairings. Know membrane transport classes: simple diffusion, facilitated diffusion, primary active transport (Na+/K+-ATPase, 3 Na+ out, 2 K+ in), and secondary cotransport.
312 words, about 2 min02Genetics and Genomics: Transmission, Variation, and Genome-Scale Reasoning
Master Mendelian ratios and their deviations: incomplete dominance, codominance, epistasis (recessive, dominant, duplicate), and linkage with recombination frequency as a map proxy. Know sex-linked inheritance patterns and how to distinguish them from autosomal traits by pedigree.
293 words, about 1 min03Biochemistry and Metabolism: Energetics, Enzyme Kinetics, and Pathway Logic
Know the major catabolic and anabolic routes and their regulation: glycolysis, pyruvate dehydrogenase, the citric acid cycle, oxidative phosphorylation, gluconeogenesis, glycogen metabolism, the pentose phosphate pathway, fatty acid oxidation and synthesis, and amino acid transamination. Track the key regulated enzymes (phosphofructokinase-1, pyruvate dehydrogenase, isocitrate dehydrogenase, glycogen phosphorylase, acetyl-CoA carboxylase) and their allosteric and covalent controls.
274 words, about 1 min04Organismal Biology: Structure-Function Integration Across Systems
Expect questions spanning animal and plant physiology: circulation (cardiac cycle, pressure-volume relationships, capillary exchange), respiration (gas laws, hemoglobin dissociation curve, ventilation-perfusion matching), osmoregulation and nephron transport, endocrine feedback loops (hypothalamic-pituitary axes, insulin/glucagon), neural signaling (resting potential, action potential phases, synaptic transmission), muscle contraction (sliding filament, calcium handling), and plant transport (xylem tension, phloem pressure flow). Homeostasis is the unifying theme: negative feedback stabilizes, positive feedback amplifies and must terminate.
285 words, about 1 min05Ecology and Evolution: Mechanisms, Models, and Evidence
Understand evolutionary mechanisms-mutation, selection, drift, gene flow, nonrandom mating-and the conditions for Hardy-Weinberg equilibrium. Know species concepts and speciation modes (allopatric, sympatric, polyploidy), reproductive isolating barriers, and phylogenetic reasoning (synapomorphy vs homoplasy, parsimony, molecular clocks).
254 words, about 1 min06Quantitative Reasoning and Data Analysis: Estimation, Uncertainty, and Inference
Be comfortable with descriptive statistics (mean, median, variance, standard deviation, standard error), distributions, and the logic of hypothesis testing: null and alternative hypotheses, Type I and Type II error, p-values as tail probabilities under the null, confidence intervals, and statistical power. Know when to use common tests-t-test, chi-square, ANOVA, correlation versus regression-and understand effect size versus significance.
300 words, about 2 min07Experimental Design and Laboratory Methods: Controls, Replication, and Validation
Understand the architecture of a sound experiment: a clear hypothesis, an appropriate control (negative, positive, vehicle, sham), randomization, blinding, biological versus technical replication, and pre-specified analysis. Know common techniques and what they actually measure-PCR and qPCR, gel electrophoresis, western blotting, ELISA, microscopy and fluorescence, flow cytometry, chromatography, mass spectrometry, and sequencing.
273 words, about 1 min