Lebanese University Faculty of Medical Sciences Entrance Examination - Second Year, General Medicine cheat sheet

Central dogma: DNA → RNA → protein; transcription occurs in the nucleus (eukaryotes), translation on ribosomes in the cytoplasm or rough ER.

Membrane transport decision rule: O2, CO2, steroids cross by simple diffusion; glucose and ions need carriers or channels; macromolecules use vesicular transport.

Na+/K+-ATPase pumps 3 Na+ out and 2 K+ in per ATP hydrolyzed, maintaining resting membrane potential and osmotic balance.

Michaelis–Menten: v = Vmax[S]/(Km + [S]); Km equals the substrate concentration at half-maximal velocity and inversely reflects enzyme affinity.

Competitive inhibitors raise apparent Km with unchanged Vmax; non-competitive inhibitors lower Vmax with unchanged Km.

DNA replication is semiconservative and proceeds 5'→3' by DNA polymerase; the leading strand is continuous, the lagging strand is made in Okazaki fragments.

Mitochondrial oxidative phosphorylation yields roughly 30–32 ATP per glucose; glycolysis (cytosol) nets 2 ATP and 2 NADH.

Cell cycle checkpoints: G1/S (DNA damage, size), G2/M (replication complete), and spindle assembly checkpoint at metaphase.

Mendel's law of segregation: two alleles separate during meiosis I; independent assortment applies only to genes on different chromosomes or far apart on the same chromosome.

Monohybrid cross Aa × Aa gives 1:2:1 genotype and 3:1 phenotype; dihybrid AaBb × AaBb gives 9:3:3:1.

Test cross with a homozygous recessive reveals the genotype of a dominant-phenotype individual.

Hardy–Weinberg: p + q = 1 and p² + 2pq + q² = 1; allele frequencies stay constant without selection, mutation, migration, drift, or non-random mating.

X-linked recessive traits affect males more; an affected father cannot pass the allele to sons but transmits it to all daughters (carriers).

Codominance (AB blood type) shows both alleles; incomplete dominance (pink snapdragons) gives an intermediate phenotype.

Pedigree rule: two affected parents with an unaffected child indicates a dominant trait; unaffected parents with an affected child indicates recessive.

Karyotype notation: 47,XX,+21 = female with trisomy 21; 46,XY = normal male karyotype.

Moles: n = m/M = N/NA = V/22.4 L at STP for gases; NA = 6.022 × 10²³ mol⁻¹.

pH = −log[H⁺]; pOH = −log[OH⁻]; pH + pOH = 14 at 25 °C; strong acid pH requires full dissociation.

Henderson–Hasselbalch: pH = pKa + log([A⁻]/[HA]); buffer capacity is maximal when pH = pKa.

Ideal gas law: PV = nRT with R = 8.314 J·mol⁻¹·K⁻¹; temperature must be in kelvin.

Oxidation numbers: O is usually −2, H is +1, sum equals the overall charge; oxidation is loss of electrons, reduction is gain.

Periodic trends: atomic radius decreases left→right and increases top→bottom; electronegativity and ionization energy increase left→right and up a group.

Solubility rule: most nitrates, acetates, and alkali-metal salts are soluble; AgCl, BaSO4, and PbI2 are sparingly soluble.

Le Chatelier: adding reactant shifts right; increasing pressure shifts toward fewer gas moles; a catalyst changes rate only, not position.

Functional-group priority for naming: carboxylic acid > ester > amide > nitrile > aldehyde > ketone > alcohol > amine > alkene > alkyne > alkane.

Markovnikov's rule: H adds to the carbon with more hydrogens; anti-Markovnikov addition occurs with HBr and peroxides (radical mechanism).

SN1 proceeds via carbocation intermediate, favored by tertiary substrates and polar protic solvents; SN2 is concerted and favored by primary substrates and polar aprotic solvents.

Elimination (E2) uses a strong base and is anti-periplanar; higher temperature favors elimination over substitution.

Nucleophilic acyl substitution on acid chlorides is fastest, then anhydrides, esters, and amides; amides are least reactive due to resonance.

Aldehydes are more reactive than ketones toward nucleophilic addition; Tollens' reagent tests aldehydes (silver mirror).

Chirality requires a carbon with four different groups; a racemic mixture has zero net optical rotation.

Aromaticity (Hückel): cyclic, planar, fully conjugated, 4n + 2 π electrons; benzene has 6 π electrons and undergoes substitution, not addition.

Kinematics: v = v₀ + at; x = v₀t + ½at²; v² = v₀² + 2ax (constant acceleration only).

Newton's second law: ΣF = ma; weight W = mg with g ≈ 9.8 m·s⁻² near Earth's surface.

Work–energy theorem: W = ΔKE = ½mv² − ½mv₀²; gravitational potential energy near Earth U = mgh.

Conservation of momentum: m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂' for isolated systems; kinetic energy is conserved only in elastic collisions.

Ohm's law V = IR; power P = VI = I²R = V²/R; resistors in series add, in parallel 1/R = Σ1/Rᵢ.

Snell's law: n₁sinθ₁ = n₂sinθ₂; total internal reflection occurs when the incidence angle exceeds the critical angle sinθc = n₂/n₁.

Ideal gas kinetic theory: average kinetic energy depends only on temperature, KE = (3/2)kBT per molecule.

Simple harmonic motion: T = 2π√(m/k) for a spring; T = 2π√(L/g) for a pendulum; period is independent of amplitude.

Quadratic formula: x = (−b ± √(b² − 4ac))/(2a); discriminant Δ = b² − 4ac gives two, one, or no real roots.

Derivative rules: (xⁿ)' = nxⁿ⁻¹; (eˣ)' = eˣ; (ln x)' = 1/x; product rule (uv)' = u'v + uv'; chain rule d/dx f(g(x)) = f'(g(x))g'(x).

Definite integral as area: ∫ₐᵇ f(x)dx = F(b) − F(a) for an antiderivative F.

Limits: lim(x→0) sin x/x = 1; lim(x→0)(1 − cos x)/x = 0; L'Hôpital applies to 0/0 or ∞/∞ forms.

Logarithm rules: log(ab) = log a + log b; log(a/b) = log a − log b; log(aⁿ) = n log a; log_b a = ln a/ln b.

Trigonometric identities: sin²x + cos²x = 1; sin 2x = 2 sin x cos x; cos 2x = cos²x − sin²x.

Arithmetic sequence: uₙ = u₁ + (n−1)r; geometric sequence uₙ = u₁qⁿ⁻¹ with sum u₁(1 − qⁿ)/(1 − q) for q ≠ 1.

Vector dot product a·b = |a||b|cosθ; perpendicular when a·b = 0; cross product magnitude |a||b|sinθ gives parallelogram area.

Cardiac output = heart rate × stroke volume; normal resting output is about 5 L·min⁻¹.

Blood flow follows the pressure gradient; the largest pressure drop occurs across arterioles, which are the main resistance vessels.

Oxygen–hemoglobin dissociation curve shifts right (lower affinity) with increased CO2, H⁺, temperature, and 2,3-BPG (Bohr effect).

Nephron order: glomerulus → proximal tubule → loop of Henle → distal tubule → collecting duct; glucose reabsorption occurs mainly in the proximal tubule.

Spirometry: tidal volume ≈ 500 mL; vital capacity = inspiratory reserve + tidal + expiratory reserve; residual volume cannot be exhaled.

Hormone axes: hypothalamus → anterior pituitary → target gland; insulin lowers blood glucose, glucagon raises it.

Action potential phases: depolarization by Na⁺ influx, repolarization by K⁺ efflux, hyperpolarization, then Na+/K+ pump restores gradients.

Blood circulation: systemic veins → right atrium → right ventricle → pulmonary artery → lungs → left atrium → left ventricle → aorta.

Hypothesis must be falsifiable and testable; a prediction states an observable outcome if the hypothesis holds.

Independent variable is manipulated; dependent variable is measured; controlled variables are held constant to avoid confounding.

A control group isolates the effect of the treatment; randomization reduces selection bias; blinding reduces observer bias.

Correlation does not imply causation; a plausible confounder can explain an observed association.

Sensitivity = true positives/(true positives + false negatives); specificity = true negatives/(true negatives + false positives).

Positive predictive value depends on prevalence, so a test's PPV falls when disease prevalence in the tested population is low.

Significance: p-value is the probability of data at least as extreme given the null hypothesis; it is not the probability the null is true.

Reading a graph: check axis units and scale, note error bars (SD vs SEM), and distinguish absolute from relative changes.

Prefixes: hyper- (above normal), hypo- (below normal), tachy- (fast), brady- (slow), dys- (disordered), a-/an- (absence).

Suffixes: -itis (inflammation), -ectomy (surgical removal), -otomy (incision), -osis (condition/degeneration), -emia (blood condition), -uria (urine condition).

Roots: cardio- (heart), nephro- (kidney), hepato- (liver), pulmo- (lung), neuro- (nerve), osteo- (bone), derm- (skin).

Anatomical position: standing upright, face forward, palms forward; proximal means closer to the trunk, distal farther away.

Directional terms: superior (above), inferior (below), anterior (front), posterior (back), medial (toward midline), lateral (away from midline).

SI units: length metre (m), mass kilogram (kg), time second (s), amount mole (mol), temperature kelvin (K); derived unit of force is the newton.

Significant figures: multiplication/division keep the least number of sig figs; addition/subtraction keep the least number of decimal places.

Scientific writing: report mean ± SD with n, state units, avoid causal language for correlational data, and cite primary sources.

Organelle functions: ribosome synthesizes protein, rough ER folds and modifies protein, Golgi sorts and packages, lysosome degrades, mitochondrion produces ATP.

Prokaryotes lack a nucleus and membrane-bound organelles; they have a nucleoid, 70S ribosomes, and a peptidoglycan wall.

Cell membrane is a phospholipid bilayer with embedded proteins and cholesterol; it is selectively permeable and described by the fluid mosaic model.

DNA structure: antiparallel double helix, A pairs with T (2 H-bonds), G pairs with C (3 H-bonds); purines are A and G, pyrimidines are T and C.

Transcription: RNA polymerase reads the template 3'→5' and synthesizes mRNA 5'→3'; in eukaryotes introns are spliced out before translation.

Codon table rule: 64 codons encode 20 amino acids; AUG is the start codon and UAA, UAG, UGA are stop codons.

Mitosis stages: prophase (chromosomes condense), metaphase (align at equator), anaphase (sister chromatids separate), telophase (nuclei reform).

Meiosis produces four haploid cells; crossing over in prophase I and independent assortment in metaphase I generate genetic diversity.

Genotype vs phenotype: genotype is the allele combination; phenotype is the observable trait resulting from genotype and environment.

Homozygous means two identical alleles; heterozygous means two different alleles; a carrier is heterozygous for a recessive disease.

Punnett square for Aa × aa gives 50% Aa and 50% aa, so half the offspring show the recessive phenotype.

Autosomal dominant inheritance: affected individuals appear in every generation; each affected child has a 50% risk if one parent is heterozygous.

Blood type inheritance: IA and IB are codominant; i is recessive, so type O is ii and type AB is IAIB.

Mutation types: substitution (may be silent, missense, or nonsense), insertion/deletion (frameshift), and chromosomal (deletion, duplication, translocation).

Nondisjunction in meiosis causes aneuploidy such as trisomy 21 (Down syndrome) or monosomy X (Turner syndrome).

Sex determination: the father's sperm determines sex; an X-bearing sperm yields XX (female), a Y-bearing sperm yields XY (male).

Atomic structure: atomic number Z = protons; mass number A = protons + neutrons; isotopes differ in neutrons only.

Electron configuration follows Aufbau, Pauli exclusion, and Hund's rule; for example, Na is 1s²2s²2p⁶3s¹.

Bond type: metal + nonmetal gives ionic; nonmetal + nonmetal gives covalent; metallic bonding occurs among metal atoms.

Molarity M = moles of solute/litres of solution; dilution rule M₁V₁ = M₂V₂.

Stoichiometry requires a balanced equation; limiting reagent is the reactant that produces the least product.

Acid–base: strong acids (HCl, HNO3, H2SO4) dissociate fully; weak acids (CH3COOH) partially dissociate with Ka.

Electrochemistry: oxidation at the anode, reduction at the cathode; in a galvanic cell electrons flow from anode to cathode.

Bond polarity arises from electronegativity difference; a molecule is polar if bond dipoles do not cancel (H2O polar, CO2 nonpolar).

Alkane general formula CnH2n+2; alkenes CnH2n; alkynes CnH2n−2; each ring or double bond reduces hydrogen count by 2.

Isomerism: structural isomers differ in connectivity; stereoisomers (enantiomers, diastereomers) differ only in spatial arrangement.

Alcohol oxidation: primary alcohol → aldehyde → carboxylic acid; secondary alcohol → ketone; tertiary alcohol resists oxidation.

Esterification: carboxylic acid + alcohol in acid catalyst gives ester + water; hydrolysis reverses this reaction.

Grignard reagents (RMgX) are strong nucleophiles that add to carbonyls to form alcohols.

Friedel–Crafts acylation attaches an acyl group to an aromatic ring using AlCl3 as Lewis acid catalyst.

IR spectroscopy: O–H broad ~3300 cm⁻¹, C=O strong ~1700 cm⁻¹, C–H stretch ~2900 cm⁻¹.

NMR: number of signals equals number of chemically distinct proton environments; integration gives relative proton counts.

Projectile motion: horizontal velocity constant; vertical acceleration = −g; range R = v₀²sin2θ/g for launch and landing at the same height.

Circular motion: centripetal acceleration a = v²/r; centripetal force F = mv²/r directed toward the center.

Universal gravitation: F = Gm₁m₂/r²; orbital speed v = √(GM/r); period T = 2π√(r³/GM).

Pressure in a fluid: P = P₀ + ρgh; buoyant force equals weight of displaced fluid (Archimedes' principle).

Thermodynamics: ΔU = Q − W; efficiency of a heat engine η = 1 − Tc/Th.

Coulomb's law: F = kq₁q₂/r²; electric field E = F/q; potential energy U = kq₁q₂/r.

Magnetic force on a moving charge F = qvB sinθ; on a current-carrying wire F = BIL sinθ.

Wave relation: v = fλ; refraction changes speed and wavelength but not frequency.

Function composition: (f∘g)(x) = f(g(x)); inverse function f⁻¹ satisfies f(f⁻¹(x)) = x.

Exponential growth/decay: N(t) = N₀e^{kt}; k > 0 growth, k < 0 decay; half-life t½ = ln2/|k|.

Integration by parts: ∫u dv = uv − ∫v du; substitution method reverses the chain rule.

Conic sections: circle (x−h)² + (y−k)² = r²; parabola y = ax² + bx + c with vertex x = −b/2a.

Probability: P(A∪B) = P(A) + P(B) − P(A∩B); P(A|B) = P(A∩B)/P(B); independent events P(A∩B) = P(A)P(B).

Binomial distribution: P(X = k) = C(n,k)p^k(1−p)^{n−k}; mean np; variance np(1−p).

Mean, median, mode: mean is sensitive to outliers; median is the middle value; mode is most frequent.

Standard deviation σ = √(Σ(xᵢ − μ)²/n); variance is σ²; larger σ means more spread around the mean.

Digestive order: mouth → esophagus → stomach → small intestine (duodenum, jejunum, ileum) → large intestine; most absorption occurs in the small intestine.

Enzyme sources: salivary amylase (starch), pepsin (protein in stomach), pancreatic lipase (fat), trypsin (protein in small intestine).

Homeostasis: negative feedback reverses deviation (e.g., thermoregulation); positive feedback amplifies (e.g., oxytocin in labor).

Nervous system: CNS = brain and spinal cord; PNS = somatic and autonomic; autonomic divides into sympathetic (fight/flight) and parasympathetic (rest/digest).

Synaptic transmission: action potential → Ca²⁺ influx → neurotransmitter release → receptor binding → postsynaptic potential.

Kidney regulation: ADH increases water reabsorption; aldosterone increases Na⁺ reabsorption; both raise blood pressure.

Gas exchange occurs in alveoli by simple diffusion; CO2 diffuses out, O2 diffuses in, driven by partial pressure gradients.

Bone and muscle: osteoblasts build bone, osteoclasts resorb it; skeletal muscle contraction uses the sliding filament model with actin and myosin.

Experimental design order: observation → question → hypothesis → prediction → experiment → analysis → conclusion.

Bias types: selection bias (non-random groups), measurement bias (faulty instrument), and reporting bias (publishing only positive results).

Sample size affects precision, not bias; larger n narrows confidence intervals if sampling is random.

Confidence interval interpretation: a 95% CI means 95% of such intervals would contain the true parameter, not that 95% of data lie inside.

Relative risk = risk in exposed/risk in unexposed; odds ratio approximates it for rare outcomes.

Dose–response relationship and temporal sequence strengthen causal inference; reversibility (removing exposure removes effect) also supports causality.

Randomized controlled trial is the strongest design for treatment effect; cohort studies measure incidence; case–control studies suit rare diseases.

Data presentation: bar charts suit categorical data, histograms suit continuous distributions, scatter plots show correlation between two variables.

Common abbreviations: BP (blood pressure), HR (heart rate), ECG (electrocardiogram), CNS (central nervous system), DNA (deoxyribonucleic acid).

Units and conversions: 1 L = 1000 mL; 1 kg = 1000 g; 1 mmHg ≈ 133.3 Pa; body temperature ≈ 37 °C = 310 K.

Medical roots for systems: gastro- (stomach), intestino- (intestine), pulmono- (lung), cardio- (heart), renal/nephro- (kidney), hepato- (liver).

Precision vs accuracy: precision is closeness of repeated measurements to each other; accuracy is closeness to the true value.

Percent error = |measured − true|/true × 100%; percent change = (new − old)/old × 100%.

Scientific notation: 0.0034 = 3.4 × 10⁻³; 25,000 = 2.5 × 10⁴; keep one digit before the decimal point.

Abstract structure: background, objective, methods, results, conclusion; methods must allow replication.

Ethical communication: report conflicts of interest, avoid plagiarism, obtain informed consent, and do not overstate conclusions beyond the data.

ATP is the universal energy currency; hydrolysis of ATP to ADP + Pi releases about 30.5 kJ·mol⁻¹ under standard conditions.

Cellular respiration stages: glycolysis (cytosol), pyruvate oxidation and Krebs cycle (mitochondrial matrix), electron transport chain (inner membrane).

Photosynthesis: light reactions in thylakoid membranes produce ATP and NADPH; Calvin cycle in stroma fixes CO2 using RuBisCO.

Apoptosis is programmed cell death with controlled packaging; necrosis is uncontrolled cell death with inflammation.

Signal transduction order: receptor binding → intracellular cascade → effector response; G-protein-coupled receptors activate second messengers such as cAMP.

Cell junctions: tight junctions seal, desmosomes anchor cells, gap junctions allow ion and small-molecule passage.

Enzyme activity increases with temperature up to optimum, then denatures; pH also has an optimum specific to each enzyme.

PCR steps: denaturation (~95 °C), annealing of primers (~55 °C), extension by Taq polymerase (~72 °C), repeated in cycles.

DNA replication enzymes: helicase unwinds, primase lays RNA primer, DNA polymerase extends, ligase joins Okazaki fragments.

Transcription and translation in prokaryotes are coupled; in eukaryotes they are separated by the nuclear envelope.

Genetic code is degenerate (multiple codons per amino acid) but unambiguous (each codon specifies one amino acid).

Recombination frequency between two genes approximates genetic distance in centimorgans; 1% recombination ≈ 1 cM.

Mitochondrial inheritance is maternal; both sons and daughters inherit, but only daughters transmit.

Polygenic traits show continuous variation and are influenced by many genes plus environment (e.g., height).

Epistasis occurs when one gene masks or modifies the expression of another gene.

Genetic screening: a carrier test identifies heterozygotes; prenatal diagnosis (amniocentesis, CVS) detects fetal chromosomal anomalies.

Balancing redox in acidic solution: balance atoms, balance O with H2O, balance H with H⁺, balance charge with electrons, then equalize electron transfer.

Entropy and spontaneity: ΔG = ΔH − TΔS; reaction is spontaneous when ΔG < 0.

Equilibrium constant K: large K favors products; K depends on temperature only, not on initial concentrations.

Colligative properties depend on particle number: boiling point elevation ΔTb = Kb·m·i; freezing point depression ΔTf = Kf·m·i.

Radioactivity: alpha decay reduces mass number by 4 and atomic number by 2; beta-minus decay increases atomic number by 1.

Coordination compounds: ligand is a Lewis base donating an electron pair; coordination number counts donor atoms bound to the metal.

Transition metals show variable oxidation states and form colored complexes due to d–d electronic transitions.

Gas laws combined: P₁V₁/T₁ = P₂V₂/T₂ at constant amount; Avogadro's law states equal volumes of gases at same T and P contain equal moles.

Hybridization: sp³ tetrahedral (109.5°), sp² trigonal planar (120°), sp linear (180°).

Alkene addition reactions: hydrogenation (H2/Pd), halogenation (Br2), hydrohalogenation (HX), hydration (H2O/H⁺).

Aromatic substitution: nitration (HNO3/H2SO4), halogenation (X2/FeX3), sulfonation (SO3/H2SO4); activating groups direct ortho/para, deactivating groups direct meta.

Amine basicity increases with alkyl groups (electron donating) and decreases with aromatic attachment (resonance delocalization).

Carboxylic acid derivatives reactivity order: acid chloride > anhydride > ester > amide; amide is least reactive due to resonance.

Chirality: R/S assignment uses Cahn–Ingold–Prelog priority by atomic number; rotate to put lowest priority away, then read 1→2→3.

Aldol condensation: enolate attacks a carbonyl to form a β-hydroxy carbonyl, which can dehydrate to an α,β-unsaturated carbonyl.

Mass spectrometry: molecular ion peak gives molecular mass; fragmentation pattern helps identify structure.

Energy units: 1 eV = 1.6 × 10⁻¹⁹ J; work done by a constant force W = Fd cosθ.

Rotational motion: torque τ = rF sinθ; moment of inertia depends on mass distribution; angular momentum L = Iω.

Fluid flow: continuity equation A₁v₁ = A₂v₂; Bernoulli's equation P + ½ρv² + ρgh = constant along a streamline.

Electromagnetic induction: Faraday's law ε = −dΦ/dt; Lenz's law states induced current opposes the change in flux.

Photoelectric effect: photon energy E = hf; threshold frequency f₀ = W/h where W is the work function.

Atomic spectra: energy levels quantized; photon emitted when electron drops from higher to lower level, E = hf = ΔE.

Capacitors in series: 1/C = Σ1/Cᵢ; in parallel C = ΣCᵢ; energy stored U = ½CV².

Radioactive decay: N(t) = N₀e^{−λt}; half-life t½ = ln2/λ; activity A = λN.

Polynomial factorization: a² − b² = (a − b)(a + b); a³ ± b³ = (a ± b)(a² ∓ ab + b²).

Rational function asymptotes: vertical where denominator = 0 (if numerator ≠ 0); horizontal determined by degree comparison.

Matrix multiplication is not commutative; AB ≠ BA in general; determinant of 2×2 [[a,b],[c,d]] = ad − bc.

Linear system solution: Cramer's rule uses determinants; unique solution exists when the determinant is nonzero.

Sequences: arithmetic mean between a and b is (a + b)/2; geometric mean is √(ab).

Trigonometric values: sin 30° = 1/2, cos 30° = √3/2, sin 45° = √2/2, tan 45° = 1.

Derivative applications: f'(x) = 0 locates extrema; f''(x) > 0 indicates a local minimum.

Integral of 1/x is ln|x| + C; integral of eˣ is eˣ + C; integral of cos x is sin x + C.

Blood components: plasma (~55%), red blood cells (erythrocytes, carry O2 via hemoglobin), white blood cells (immunity), platelets (clotting).

Heart conduction order: SA node → AV node → bundle of His → Purkinje fibers; SA node sets the resting rhythm (~70 beats/min).

ECG waves: P = atrial depolarization, QRS = ventricular depolarization, T = ventricular repolarization.

Respiratory control: medulla oblongata sets rhythm; chemoreceptors respond mainly to rising CO2/H⁺ rather than falling O2.

Endocrine glands: thyroid (T3, T4, calcitonin), parathyroid (PTH), adrenal cortex (cortisol, aldosterone), pancreas (insulin, glucagon).

Immune response: B cells produce antibodies (humoral); T cells mediate cellular immunity; memory cells give long-term protection.

Skeletal system functions: support, protection, movement, mineral storage, and blood cell production in bone marrow.

Body fluid compartments: intracellular fluid ~2/3 of total body water; extracellular fluid includes plasma and interstitial fluid.

Study types: cross-sectional measures at one time; cohort follows over time; case–control compares past exposures; RCT randomizes intervention.

Measurement scales: nominal (categories), ordinal (ordered), interval (equal spacing, arbitrary zero), ratio (true zero).

Mean vs median: use median for skewed data; use mean ± SD for approximately symmetric data.

Type I error = rejecting a true null (α); type II error = failing to reject a false null (β); power = 1 − β.

Effect size measures strength independent of sample size; a very small p-value can reflect a large sample, not a large effect.

Confidence interval excluding the null value corresponds to statistical significance at the matching α level.

Survival analysis: Kaplan–Meier curves estimate time-to-event; log-rank test compares curves.

Graph interpretation: slope gives rate of change; area under a curve often gives total accumulated quantity.

Diagnostic suffixes: -gram (record/image), -graphy (process of recording), -scopy (visual examination), -pathy (disease), -plasty (surgical repair).

Number prefixes: mono- (one), di- (two), tri- (three), tetra- (four), poly- (many); used in chemistry and anatomy.

Common lab abbreviations: CBC (complete blood count), Hb (hemoglobin), WBC (white blood cells), RBC (red blood cells), ESR (erythrocyte sedimentation rate).

Anatomical planes: sagittal divides left/right; coronal divides front/back; transverse divides upper/lower.

Body cavities: cranial, spinal, thoracic (heart, lungs), abdominal, pelvic; diaphragm separates thoracic from abdominal.

Statistical notation: x̄ = sample mean, μ = population mean, s = sample SD, σ = population SD, n = sample size.

Reporting results: state the test used (t-test, chi-square, ANOVA), the statistic value, degrees of freedom, and p-value.

Peer review and reproducibility: describe methods in enough detail for replication, share data when possible, and disclose funding sources.