← MCAT Prep MCAT Bio/Biochem Passage Practice 25 experimental passages (142 questions) across Bio/Biochem disciplines — the passage-based reps this section is built on. Practice one at a time with full explanations, or run the whole set.
Practice all 25 passages Timed section — 59 Q · 95 min
Timed sections run at real AAMC length with a hard clock and a 118–132 section score; untimed practice shows explanations passage by passage.
biochemistry Kinetics of a Bacterial Phosphatase Alkaline phosphatase (AP) hydrolyzes phosphate monoesters, releasing inorganic phosphate. Researchers purified…
5 questions
molecular biology A Transcriptional Repressor Probed by Knockout and Reporter Assays Gene R encodes a transcription factor hypothesized to repress gene T in mammalian liver cells. To test this, i…
5 questions
cell biology Glucose Uptake and a Signaling Cascade in Muscle Cells In skeletal muscle, insulin stimulates glucose uptake by promoting translocation of the GLUT4 transporter from…
5 questions
genetics A Recessive Disorder in a Family Pedigree and Population A metabolic disorder, condition Q, follows autosomal recessive inheritance. Affected individuals are homozygou…
5 questions
physiology Renal Handling of Glucose and the Transport Maximum In the kidney, plasma is filtered at the glomerulus, and the proximal tubule reabsorbs filtered glucose using …
5 questions
microbiology Bacterial Growth and the Mechanism of an Antibiotic A team studied an E. coli culture grown in liquid medium, monitoring density by optical density at 600 nm (OD6…
5 questions
metabolism Mitochondrial Oxygen Consumption and Respiratory Inhibitors Cellular respiration couples the oxidation of fuels to ATP synthesis. In oxidative phosphorylation, the electr…
5 questions
biochemistry Characterizing a Protein by Electrophoresis and Chromatography A laboratory purified a soluble enzyme, protein P, and characterized it using gel electrophoresis and size-exc…
6 questions
molecular biology Detecting a Mutation by PCR and Gel Electrophoresis A clinical laboratory developed a test for a disease allele caused by a single base substitution that creates …
5 questions
immunology Antibody Responses Measured by ELISA The adaptive immune response generates antibodies specific to a pathogen. On first exposure to an antigen, the…
5 questions
molecular biology A Distal Enhancer Controls Liver-Specific Transcription Gene LPX encodes a lipid-processing enzyme that is abundantly transcribed in hepatocytes and undetectable in s…
6 questions
molecular biology A CRISPR-Cas9 Screen for Oxidative-Stress Survival Genes To identify genes required for survival under oxidative stress, investigators used a pooled CRISPR-Cas9 loss-o…
5 questions
molecular biology A Splice-Site Variant Tested in a Minigene Assay A child with a recessive metabolic disorder was found to be homozygous for the variant c.942+1G>A in gene MTX.…
5 questions
genetics Bisulfite Sequencing of an Imprinting Control Region The mouse Igf2 and H19 genes sit about 90 kb apart and share a set of downstream enhancers. Between them lies …
6 questions
cell biology Telomere Attrition and Replicative Senescence in Cultured Cells Investigators serially passaged a primary human fibroblast strain, HF-1, and tracked two variables as a functi…
5 questions
physiology Baroreflex Responses to Head-Up Tilt and Exercise Mean arterial pressure (MAP) is the product of cardiac output (CO) and total peripheral resistance (TPR), MAP …
6 questions
physiology Oxygen Binding Curves Under Bohr-Shift Conditions Hemoglobin (Hb) is an \alpha2\beta2 tetramer that binds up to four O2 molecules. Binding is cooperative: occup…
6 questions
physiology Measuring Insulin Sensitivity with a Euglycemic Clamp The hyperinsulinemic-euglycemic clamp is the reference method for quantifying whole-body insulin sensitivity. …
6 questions
physiology Patch-Clamp Analysis of a Skeletal Muscle Sodium Channelopathy Members of a family with paramyotonia carry a missense mutation in SCN4A, the gene encoding the voltage-gated …
5 questions
physiology Bile Acid Sequestration and Intestinal Lipid Absorption Bile acids are amphipathic cholesterol derivatives synthesized in hepatocytes, conjugated to glycine or taurin…
5 questions
microbiology Blocking Three Steps of the Retroviral Life Cycle HIV-1 is a retrovirus. Its genome is positive-sense single-stranded RNA, but that RNA is not translated direct…
6 questions
microbiology Transfer of Plasmid-Borne Resistance by Conjugation Antibiotic resistance genes often reside on conjugative plasmids that move horizontally between bacterial cell…
5 questions
cell biology The DNA-Damage Checkpoint Measured by Flow Cytometry Proliferating cells monitor genome integrity at checkpoints before committing to DNA replication or mitosis. T…
6 questions
genetics Mapping Two Autosomal Genes by Testcross Two autosomal genes were studied in Drosophila. The b gene affects body color, with the wild-type allele givin…
5 questions
immunology Adjuvants, T-Cell Help, and Immune Memory A protein antigen that has never been encountered elicits a slow, modest antibody response, whereas a second e…
5 questions
Discrete questions Discrete Questions The following questions are independent of any passage — each stands alone, as in the discrete sets on the rea…
9 questions