DAT Quantitative Reasoning flashcards
DAT Quantitative Reasoning · Build recall with a focused review session.
31 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Semiconservative replication
- Each new DNA double helix contains one original parental strand and one newly synthesized strand, because helicase unwinds the duplex and each template strand directs synthesis of a complement.
- Michaelis constant Km
- The substrate concentration at which an enzyme reaches half its maximum velocity; a low Km indicates high enzyme affinity for substrate, while a high Km indicates weak binding.
- Dihybrid 9:3:3:1 ratio
- Phenotype ratio from crossing two double heterozygotes when genes assort independently: 9/16 show both dominant traits, 3/16 each mixed class, and 1/16 both recessive.
- Ideal gas law
- PV = nRT relates pressure, volume, moles, and absolute temperature; with R = 0.0821 L·atm/(mol·K), one mole of ideal gas occupies 22.4 L at STP.
- Le Chatelier's principle
- A system at equilibrium shifts to partially offset a disturbance: adding reactant shifts right, removing product shifts right, and heating favors the endothermic direction.
- pH of strong vs weak acid
- Strong acids fully dissociate, so [H+] equals the acid concentration; weak acids partially dissociate and require Ka to find [H+] before computing pH = −log[H+].
- Newton's second law on incline
- F = ma; on a frictionless incline of angle θ, the downhill gravity component is mg·sinθ, the normal force is mg·cosθ, and acceleration along the plane is g·sinθ.
- Resistors in parallel
- Reciprocal resistance adds: 1/R = 1/R₁ + 1/R₂, so equivalent resistance is less than the smallest individual resistor and current divides among branches.
- Angle ranking strategy
- Judge angles by the width of the opening between the legs, not by leg length; a wide opening with short legs is larger than a narrow opening with long legs.
- Cube counting painted faces
- Count only exterior painted faces of stacked cubes; a cube touching another on one face shows one fewer painted face, and interior cubes show none.
- Punch on a fold line
- A hole punched exactly on a crease produces a single merged hole when unfolded, whereas a punch away from the crease produces two mirror-image holes.
- Unfolding paper punches
- To find the original hole pattern, unfold by reflecting each punch across the crease in reverse order of folding, merging any holes that overlap.
- Top-front-end view matching
- Top view gives width and depth, front view gives width and height, end view gives depth and height; shared dimensions between adjacent views must agree exactly.
- Aperture passing rule
- A solid passes through an opening only if its silhouette projected along the direction of travel fits entirely inside the opening's outline at every point.
- Opposite faces on a cube
- Faces separated by one face in a net become opposite faces on the folded cube and never share an edge; use this to eliminate impossible pattern-fold answers.
- Mental rotation preserves angles
- Rotating a shape in space preserves all distances and angles, whereas a mirror image reverses chirality and cannot be made to coincide by rotation alone.
- Author's tone indicators
- Evaluative words such as 'unfortunately,' 'remarkably,' or 'flawed' reveal the author's attitude; tone answers must match the passage's diction rather than the topic.
- Thesis location
- The main claim usually appears in the first or last paragraph, often after a concession; supporting paragraphs provide evidence, and a counterargument may be acknowledged.
- Inference question rule
- The correct inference follows necessarily from stated evidence; an answer that is plausible but not supported by the passage is a distractor.
- EXCEPT question method
- Three choices are directly supported by the passage and one is not; verify each supported choice against a specific line, and the unsupported choice is the answer.
- Scope trap answers
- Answers that are too broad, too narrow, or introduce outside information are typically wrong; the correct answer stays within the passage's stated scope.
- Correlation versus causation
- A passage may describe an association without claiming one variable causes the other; answers that upgrade correlation to causation are unsupported.
- Vocabulary in context
- Substitute each answer choice into the original sentence and select the one that preserves the sentence's meaning, ignoring the word's most common dictionary sense.
- Successive percent change
- Percent changes multiply rather than add: a 20% increase followed by a 25% decrease gives 1.20 × 0.75 = 0.90, a net 10% decrease.
- Combined work rate
- Rates add reciprocally: 1/t₁ + 1/t₂ = 1/t_total, so two workers finishing in 4 and 6 hours together complete the job in 2.4 hours.
- Average speed
- Average speed equals total distance divided by total time, not the arithmetic mean of the speeds; equal distances at different speeds require the harmonic mean.
- Combinations formula
- nCr = n!/(r!(n−r)!) counts unordered selections of r items from n; order does not matter, unlike permutations nPr = n!/(n−r)!.
- Probability of at least one
- P(at least one) = 1 − P(none); for independent trials, P(none) is the product of each trial's failure probability.
- Quadratic discriminant
- For ax² + bx + c = 0, the discriminant b² − 4ac gives two real roots when positive, one repeated root when zero, and no real roots when negative.
- Circle area and circumference
- Area = πr² and circumference = 2πr; a sector's area is (θ/360)πr² and its arc length is (θ/360)2πr for central angle θ in degrees.
- Logarithm product rule
- log(ab) = log a + log b and log(a/b) = log a − log b; change of base gives log_b(x) = ln x / ln b for any valid base.