UNSA Medicine Entrance Exam cheat sheet

Cell theory: all living things are made of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells by division.

DNA replication is semiconservative: each new double helix keeps one parental strand; adenine pairs with thymine (two H-bonds) and guanine with cytosine (three H-bonds).

Mendelian ratios: a monohybrid cross of two heterozygotes yields 3:1 phenotype and 1:2:1 genotype; a dihybrid cross of double heterozygotes yields 9:3:3:1.

Enzymes lower activation energy without altering the reaction's equilibrium constant; they are not consumed and are sensitive to pH and temperature denaturation.

Aerobic respiration net yield is about 30-32 ATP per glucose, versus 2 ATP net from glycolysis alone under anaerobic conditions.

Cellular respiration stages in order: glycolysis (cytosol), pyruvate oxidation and Krebs cycle (mitochondrial matrix), oxidative phosphorylation (inner membrane).

Osmosis moves water from low to high solute concentration across a semipermeable membrane; animal cells lyse in hypotonic and shrink in hypertonic solutions.

Hardy-Weinberg equilibrium requires no mutation, no migration, random mating, infinite population size, and no selection; deviations indicate evolution.

Mole relations: n = m/M, n = N/N_A with N_A = 6.022 x 10^23, and at STP one mole of ideal gas occupies 22.4 L.

Ideal gas law PV = nRT with R = 0.0821 L·atm/(mol·K) or 8.314 J/(mol·K); temperature must be in kelvin.

pH = -log[H+]; pOH = -log[OH-]; pH + pOH = 14 at 25 °C; strong acid and base solutions are computed from complete dissociation.

Le Chatelier's principle: adding reactant shifts right, raising pressure shifts toward fewer gas moles, and raising temperature favors the endothermic direction.

Oxidation is loss of electrons (increase in oxidation number); reduction is gain. In a redox reaction the oxidizing agent is itself reduced.

Bond polarity follows electronegativity differences; molecular polarity additionally requires an asymmetric geometry, so CO2 is nonpolar while H2O is polar.

Limiting reagent: divide moles of each reactant by its stoichiometric coefficient; the smallest quotient identifies the limiting species.

Colligative properties (boiling-point elevation, freezing-point depression, osmotic pressure) depend on particle count, not particle identity.

Kinematics: v = v0 + at, x = x0 + v0t + ½at², and v² = v0² + 2a(x - x0) apply only for constant acceleration.

Newton's second law F_net = ma; friction magnitude is f = μN, and static friction adjusts up to μ_s N before sliding begins.

Conservation of mechanical energy: ½mv² + mgh is constant when only conservative forces act; work done by nonconservative forces equals the change in mechanical energy.

Momentum p = mv is conserved in all collisions; kinetic energy is conserved only in elastic collisions.

Ohm's law V = IR; resistors in series add, resistors in parallel add reciprocally; power dissipated is P = IV = I²R = V²/R.

Wave relation v = fλ; for a wave crossing into a new medium the frequency stays constant while speed and wavelength change.

Lens and mirror equation 1/f = 1/d_o + 1/d_i; a positive image distance for a converging lens means a real image on the opposite side.

Ideal gas kinetic theory: average translational kinetic energy per molecule equals (3/2)k_BT, so it depends only on absolute temperature.

Quadratic formula x = (-b ± √(b² - 4ac))/(2a); the discriminant b² - 4ac gives two real, one repeated, or two complex roots.

Logarithm rules: log(ab) = log a + log b, log(a/b) = log a - log b, log(a^n) = n log a, and log_b a = ln a / ln b.

Arithmetic sequence a_n = a_1 + (n-1)d with sum n(a_1 + a_n)/2; geometric sequence a_n = a_1 r^(n-1) with sum a_1(1 - r^n)/(1 - r) for r ≠ 1.

Derivative rules: d/dx x^n = nx^(n-1), product rule (uv)' = u'v + uv', quotient rule, and chain rule (f∘g)' = f'(g(x))g'(x).

Definite integral equals the net signed area under a curve; the fundamental theorem states ∫_a^b f(x)dx = F(b) - F(a) for an antiderivative F.

Trigonometric identity sin²θ + cos²θ = 1; law of cosines c² = a² + b² - 2ab cos C; law of sines a/sin A = b/sin B.

Probability of independent events multiplies; P(A or B) = P(A) + P(B) - P(A and B); conditional probability P(A|B) = P(A and B)/P(B).

Distance between points is √((x2-x1)² + (y2-y1)²); the midpoint is the average of the coordinates; slope m = (y2-y1)/(x2-x1).

Narrative point of view: first person uses I/we, third-person limited stays inside one character's perception, and omniscient narration accesses multiple minds.

Literary devices: metaphor compares without like/as, simile uses like/as, personification grants human traits to nonhuman things, and hyperbole is deliberate exaggeration.

Irony types: verbal (saying the opposite of intent), situational (outcome contradicts expectation), and dramatic (audience knows what a character does not).

A sonnet has 14 lines; Shakespearean form uses three quatrains plus a couplet with rhyme scheme ABAB CDCD EFEF GG.

Topic versus theme: the topic is the subject matter, while the theme is the underlying insight or claim the work develops about it.

Subject-verb agreement: the verb agrees with the head noun, not with intervening prepositional phrases; indefinite pronouns such as everyone take singular verbs.

Dangling modifier: an introductory participial phrase must describe the subject of the main clause, otherwise the sentence is ill-formed.

Argument structure: a claim is supported by evidence and warrants; a valid argument's conclusion follows necessarily from its premises, soundness also requires true premises.

Classical conditioning pairs a neutral stimulus with an unconditioned stimulus until the neutral stimulus alone elicits the response; operant conditioning shapes behavior through reinforcement and punishment.

Piaget's stages in order: sensorimotor (object permanence), preoperational (egocentrism), concrete operational (conservation), formal operational (abstract reasoning).

Supply and demand: a price above equilibrium creates a surplus, a price below creates a shortage; a shift of the curve differs from movement along it.

GDP measures final goods and services produced within a country's borders in a period; it excludes intermediate goods and transfer payments.

Demographic transition stages move from high birth and death rates through falling death rates to low birth and death rates as industrialization proceeds.

Classical versus operant distinction: classical involves involuntary reflexive responses, operant involves voluntary behavior controlled by its consequences.

Correlation does not establish causation; a valid causal claim requires temporal precedence, covariation, and elimination of confounds or random assignment.

Social stratification refers to ranked, persistent inequality in access to resources, power, and prestige, reproduced through institutions such as education.

Mitosis produces two genetically identical diploid cells; meiosis produces four genetically distinct haploid gametes with crossing over in prophase I.

Photosynthesis light reactions occur in the thylakoid membrane and produce ATP and NADPH; the Calvin cycle in the stroma fixes CO2 via rubisco.

Blood flow path: right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta.

Natural selection requires heritable variation in traits that affect reproductive success; it acts on phenotypes and changes allele frequencies across generations.

Prokaryotes lack a membrane-bound nucleus and organelles; they have 70S ribosomes, whereas eukaryotes have 80S cytoplasmic ribosomes.

Taxonomic hierarchy from broad to narrow: domain, kingdom, phylum, class, order, family, genus, species.

Electron configuration follows the Aufbau principle, Pauli exclusion principle, and Hund's rule; orbitals fill 1s 2s 2p 3s 3p 4s 3d in energy order.

Periodic trends: atomic radius decreases across a period and increases down a group; electronegativity increases across and decreases down.

Empirical formula gives the simplest whole-number ratio; molecular formula is a whole-number multiple of it, found from molar mass.

Molarity M = moles of solute / liters of solution; dilution obeys M1V1 = M2V2.

Coulomb's law F = kq1q2/r²; the electric field of a point charge is E = kq/r² and points away from positive charge.

Magnetic force on a moving charge is F = qvB sin θ, perpendicular to both velocity and field, so magnetic force does no work.

Simple harmonic motion: period of a mass-spring system T = 2π√(m/k); period of a pendulum T = 2π√(L/g), independent of mass.

Heat transfer Q = mcΔT; latent heat Q = mL applies during phase change at constant temperature.

Circle equation (x-h)² + (y-k)² = r² has center (h,k) and radius r; completing the square converts general form to this.

Limits: a function is continuous at a point when the limit exists, the function is defined there, and the two agree.

Matrix multiplication is not commutative; the determinant of a 2x2 matrix [[a,b],[c,d]] is ad - bc, nonzero implying invertibility.

Expected value of a discrete random variable is Σ x·P(x); the binomial probability is C(n,k)p^k(1-p)^(n-k).

Active voice places the actor as subject; passive voice promotes the object and typically weakens directness.

Punctuation rules: a semicolon joins two independent clauses, a colon introduces a list or explanation, and a comma splice is an error.

A thesis statement presents the central arguable claim of an essay; each body paragraph should support it with evidence and analysis.

Rhetorical appeals: ethos is credibility, pathos is emotion, and logos is logical reasoning supported by evidence.

Inflation erodes purchasing power; real interest rate ≈ nominal interest rate minus inflation rate.

Opportunity cost is the value of the next-best alternative forgone when a choice is made.

Experimental design: random assignment supports causal inference, while random sampling supports generalization to a population.

Federal systems divide power between national and regional governments; unitary systems concentrate authority in the central government.