DAT PAT cheat sheet

Hardy-Weinberg equilibrium requires no mutation, no migration, random mating, no selection, and a large population; allele frequencies p + q = 1 and genotype frequencies p² + 2pq + q² = 1.

Mendelian dihybrid cross of two heterozygotes yields a 9:3:3:1 phenotypic ratio; a monohybrid heterozygote cross yields 3:1, and a testcross with a heterozygote yields 1:1.

Enzyme Michaelis-Menten: v = Vmax[S]/(Km + [S]); Km is the substrate concentration at half Vmax and is inversely related to enzyme affinity.

DNA replication is semiconservative; DNA polymerase synthesizes 5' to 3' only, so the lagging strand is made in Okazaki fragments and needs RNA primers.

Transcription in eukaryotes occurs in the nucleus and requires RNA polymerase II for mRNA; translation occurs on ribosomes and reads codons 5' to 3' using tRNA anticodons.

The citric acid cycle per glucose yields 3 NADH, 1 FADH2, 1 GTP/ATP, and 2 CO2; glycolysis nets 2 ATP and 2 NADH; oxidative phosphorylation yields roughly 26-28 ATP.

Osmosis moves water from low to high solute concentration; a cell in a hypertonic solution shrinks (crenation in animal cells, plasmolysis in plant cells).

Gas exchange in alveoli and tissue capillaries occurs by simple diffusion driven by partial-pressure gradients; oxygen binds hemoglobin cooperatively, giving a sigmoidal dissociation curve.

Newton's second law F = ma; for uniform circular motion, centripetal force Fc = mv²/r; work W = Fd cos θ and kinetic energy KE = ½mv².

Angle ranking: compare the openings, not the lengths of the drawn legs; short legs exaggerate perceived angle, so mentally extend both rays before comparing.

Cube counting: count exposed faces only, including the bottom of cubes that overhang or rest on a surface; tally faces cube by cube rather than by visible side.

Paper folding: reverse each fold in reverse order; a hole punched through n layers produces n holes, and holes reflect across the crease line of every fold that covered them.

Aperture passing: a solid passes through a hole only if its cross-section at every depth fits; check the widest cross-section against the narrowest part of the opening.

Hole punching: count layers at the punch point; unfolding reflects the hole across each fold line, and a hole on a fold line yields one merged hole, not two.

Top-front-end views: hidden edges appear as dashed lines, and a feature visible in one view must be consistent with its projected position in the other two views.

Form development: unfold a flat pattern mentally by keeping adjacent faces attached at shared edges; opposite faces on a cube never share an edge.

Spatial relations: use a fixed orientation and track rotations; a 90° rotation about a vertical axis swaps front and side views but preserves top view.

Main-idea questions ask for the passage's central claim; a correct answer covers the whole passage, while a true-but-narrow detail is a trap.

Tone and attitude answers must match the author's language intensity; extreme words (never, always, completely) usually misstate a measured tone.

Inference answers must follow necessarily from stated evidence; an answer that is merely plausible or adds outside knowledge is incorrect.

Detail questions are answered by locating the exact sentence; wrong choices often swap a qualifier, reverse a cause-effect, or change a quantity.

EXCEPT and NOT questions: three choices are supported by the passage, so verify each against a line before selecting the unsupported one.

Vocab-in-context: substitute each option into the sentence and keep the one that preserves the passage's meaning, not the most common dictionary sense.

Passage structure questions track function (example, counterargument, concession); the answer describes the role of a paragraph, not its topic.

When two answers seem right, prefer the one with narrower scope and direct textual support over one requiring an unstated assumption.

Percent change = (new − old)/old × 100; successive percent changes multiply as factors, so +20% then −20% gives 0.96 of the original, a 4% net decrease.

Average = sum/count; for weighted averages, weight each group mean by its count, and the combined mean lies between the two group means.

Probability of independent events multiplies; for mutually exclusive events, add; P(A or B) = P(A) + P(B) − P(A and B).

Combinations nCr = n!/(r!(n−r)!) ignore order; permutations nPr = n!/(n−r)! count order; use combinations for committee and handshake problems.

Slope = (y2 − y1)/(x2 − x1); parallel lines share slope, perpendicular slopes multiply to −1.

Distance = rate × time; for round trips at speeds a and b over equal distances, average speed is the harmonic mean 2ab/(a + b), not (a + b)/2.

Area formulas: triangle ½bh, circle πr², trapezoid ½(b1 + b2)h; volume of a cylinder is πr²h and of a cone is ⅓πr²h.

Ratios scale by a common factor k: if sides scale by k, area scales by k² and volume by k³.

Log rules: log(ab) = log a + log b, log(a/b) = log a − log b, log(aⁿ) = n log a; log base b of x = ln x / ln b.