Your FREE OAT Flashcards 2026 – 250+ Cards

The mitochondria — site of aerobic respiration, producing most of the cell's ATP.

The ribosomes — they translate mRNA into polypeptide chains.

Stores the cell's DNA and controls gene expression and cell activity.

Modifies, packages, and ships proteins and lipids in vesicles.

Rough ER (with ribosomes) processes proteins; smooth ER makes lipids and detoxifies.

Digestion — they contain hydrolytic enzymes that break down waste and worn organelles.

Prokaryotes (bacteria) lack a membrane-bound nucleus and organelles; eukaryotes have both.

Glycolysis (cytoplasm) → Krebs/citric acid cycle (matrix) → electron transport chain (inner membrane).

2 ATP and 2 NADH per glucose; no oxygen required.

Oxygen — it combines with electrons and H⁺ to form water.

About 30–32 ATP, most made by the electron transport chain via oxidative phosphorylation.

In chloroplasts — light reactions in the thylakoid membranes, the Calvin cycle in the stroma.

Mitosis → 2 identical diploid cells (growth/repair); meiosis → 4 unique haploid gametes (reproduction).

Prophase → metaphase → anaphase → telophase (PMAT), then cytokinesis.

Exchange of genetic material between homologous chromosomes in meiosis I — creates genetic variation.

DNA → RNA → protein (replication, transcription, translation).

Adenine–Thymine and Guanine–Cytosine (A–T, G–C).

Uracil (U) pairs with adenine instead of thymine.

Each parent's two alleles separate so each gamete carries one allele for a trait.

1 BB : 2 Bb : 1 bb (1:2:1); phenotype ratio is 3 dominant : 1 recessive.

p + q = 1 and p² + 2pq + q² = 1, where 2pq is the heterozygote frequency.

No mutation, no migration, no selection, random mating, and a large population.

A biological catalyst that lowers a reaction's activation energy without being consumed.

The region of an enzyme where the substrate binds and the reaction occurs.

Vein → atrium → valve → ventricle → valve → artery (right side deoxygenated, left side oxygenated).

Right side = tricuspid (3 cusps); left side = bicuspid/mitral (2 cusps). LAB RAT mnemonic.

The left ventricle — it pumps oxygenated blood to the entire body.

The pulmonary artery (the famous exception — arteries usually carry oxygenated blood).

The nephron — it filters blood and forms urine.

The neuron — dendrites receive signals, the axon transmits the impulse.

About −70 mV; maintained by the Na⁺/K⁺ pump moving 3 Na⁺ out and 2 K⁺ in.

Archaebacteria, Eubacteria, Protista, Fungi, Plantae, Animalia.

No — they lack cells and metabolism and must hijack a host cell to replicate.

Arteries carry blood away from the heart (thick, muscular); veins carry blood toward the heart (have valves).

Differential survival and reproduction of individuals with favorable heritable traits.

Producers (autotrophs) make their own food; consumers (heterotrophs) eat other organisms.

A position in a food chain; only ~10% of energy passes to the next level.

The maintenance of a stable internal environment despite external changes.

Diffusion = movement of solute down its gradient; osmosis = movement of water across a membrane.

A cell shrinks in hypertonic (more solute outside) and swells in hypotonic (less solute outside).

A selectively permeable phospholipid bilayer that controls what enters and leaves the cell.

Active transport requires ATP and moves substances against the gradient; passive transport does not.

Lactic acid (lactate) fermentation, regenerating NAD⁺ so glycolysis can continue without oxygen.

In the mitochondrial matrix; it releases CO₂ and produces NADH, FADH₂, and a little ATP.

Transcription of DNA to mRNA followed by translation of mRNA into a protein.

A sequence of three mRNA nucleotides that codes for one amino acid (or a stop signal).

A dominant allele shows in the phenotype with one copy; a recessive needs two copies to show.

Genotype is the genetic makeup (alleles); phenotype is the observable trait.

Homozygous = two identical alleles (BB or bb); heterozygous = two different alleles (Bb).

The probability of offspring genotypes and phenotypes from a given cross.

Innate is fast, nonspecific (skin, phagocytes); adaptive is slower, specific, and has memory (lymphocytes).

Endocrine uses hormones in blood (slow, widespread); nervous uses electrical impulses (fast, targeted).

A pathway's end product inhibits an earlier enzyme, regulating its own production (negative feedback).

Plant cells have a cell wall, chloroplasts, and a large central vacuole; animal cells have centrioles.

PV = nRT, with R = 0.0821 L·atm/mol·K; always use absolute temperature in kelvin.

At constant temperature, P ∝ 1/V — pressure and volume are inversely related (P₁V₁ = P₂V₂).

At constant pressure, V ∝ T — volume is directly proportional to absolute temperature.

pH = −log[H⁺]; the scale runs 0–14, and pH + pOH = 14 at 25 °C.

Below 7 is acidic, exactly 7 is neutral, above 7 is basic.

An acid donates a proton (H⁺); a base accepts a proton.

Loss of electrons (oxidation number increases). OIL RIG: Oxidation Is Loss.

Gain of electrons (oxidation number decreases). OIL RIG: Reduction Is Gain.

A system at equilibrium shifts to partly offset any disturbance (concentration, pressure, temperature).

Using mole ratios from a balanced equation to relate amounts of reactants and products.

6.022 × 10²³ particles per mole.

The reactant that runs out first and therefore caps how much product can form.

Moles of solute per liter of solution (mol/L).

Endothermic absorbs heat (ΔH > 0); exothermic releases heat (ΔH < 0).

The entropy (disorder) of an isolated system tends to increase over time.

ΔG = ΔH − TΔS; a reaction is spontaneous when ΔG < 0.

Increases down a group and decreases across a period (left to right).

Decreases down a group and increases across a period.

Decreases down a group and increases across a period; fluorine is highest.

Atoms of the same element with the same protons but a different number of neutrons.

An atom's tendency to attract shared electrons in a bond.

Ionic = transfer of electrons (metal + nonmetal); covalent = sharing of electrons (nonmetals).

The amount of substance containing 6.022 × 10²³ entities; equals the molar mass in grams.

A substance that increases H⁺ (H₃O⁺) concentration in water.

It lowers the activation energy, speeding a reaction without being consumed.

The time for half of a radioactive sample (or reactant) to decay or react.

Alpha emits a helium nucleus (₂⁴He); beta emits an electron and converts a neutron to a proton.

0 °C and 1 atm; one mole of ideal gas occupies 22.4 L.

Two species differing by one proton (H⁺), e.g. HCl and Cl⁻.

A strong acid fully dissociates (HCl); a weak acid only partly dissociates (acetic acid).

A solution of a weak acid and its conjugate base that resists changes in pH.

pH = pKa + log([base]/[acid]); pH equals pKa when acid and conjugate base are equal.

Raising temperature shifts an exothermic equilibrium toward reactants (heat is a product).

It speeds up both directions equally — it changes the rate, not the position of equilibrium.

A substance that dissociates into ions in solution and conducts electricity.

Stronger (higher-energy) bonds are harder to break; bond breaking absorbs energy, bond forming releases it.

Large difference → ionic; small/moderate → polar covalent; near zero → nonpolar covalent.

Molecular geometry, by arranging electron pairs around a central atom to minimize repulsion.

Tetrahedral, with bond angles of about 109.5°.

A measure of bond/molecular polarity from unequal sharing of electrons.

H bonded to N, O, or F interacting with a lone pair on another N, O, or F.

Energy is conserved: ΔU = Q − W; the internal energy of an isolated system is constant.

The slowest step in a reaction mechanism; it sets the overall reaction rate.

A catalyst is consumed early and regenerated; an intermediate is formed then used up later.

Zero (e.g., O₂, Na metal, H₂ all have oxidation number 0).

HCl, HBr, HI, HNO₃, H₂SO₄, HClO₄ (fully dissociate in water).

Moles of solute per kilogram of solvent (mol/kg) — used for colligative properties.

The number of dissolved particles (a colligative property), not their identity.

SN1 is two steps (via a carbocation); SN2 is one concerted step.

SN1 favors tertiary (3°) carbons; SN2 favors primary (1°)/methyl carbons.

SN1 gives racemization; SN2 inverts the stereocenter (backside attack).

SN1 is first order (rate = k[substrate]); SN2 is second order (rate = k[substrate][nucleophile]).

E1 is stepwise via a carbocation; E2 is concerted and needs a strong base (anti-periplanar).

A carbon bonded to four different groups, making the molecule non-superimposable on its mirror image.

Non-superimposable mirror-image molecules that rotate plane-polarized light in opposite directions.

Enantiomers are mirror images; diastereomers are stereoisomers that are NOT mirror images.

A specific atom/group giving a molecule characteristic reactivity (−OH, C=O, −COOH, −NH₂).

Hydroxyl group, −OH.

Carboxyl group, −COOH.

Both have C=O; an aldehyde's carbonyl is at the chain end (−CHO), a ketone's is internal.

Contains nitrogen, −NH₂ (or substituted).

A cyclic, planar, fully conjugated ring is aromatic if it has 4n + 2 π electrons.

Six delocalized π electrons (n = 1 in 4n + 2), making it aromatic and very stable.

In HX addition to an alkene, H adds to the carbon with more hydrogens (gives the more stable carbocation).

Functional groups via bond vibrations (e.g., a broad −OH stretch, a sharp C=O near 1700 cm⁻¹).

The number, environment, and neighbors of hydrogen atoms — mapping the carbon-hydrogen skeleton.

Same molecular formula but different connectivity of atoms.

Geometric isomers about a double bond/ring — cis = same side, trans = opposite sides.

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

A nucleophile donates an electron pair (electron-rich); an electrophile accepts one (electron-poor).

3° > 2° > 1° > methyl — more alkyl groups stabilize the positive charge.

Saturated = only single C–C bonds (alkanes); unsaturated = has double/triple bonds.

Delocalization of electrons over multiple structures; the real molecule is a hybrid, which adds stability.

Gives an aldehyde (mild oxidant) or a carboxylic acid (strong oxidant).

Protic solvents (water, alcohols) have O–H/N–H and favor SN1/E1; aprotic (acetone, DMSO) favor SN2/E2.

Better leaving groups are weak bases — e.g., I⁻ > Br⁻ > Cl⁻; tosylate is excellent.

Alkanes have C–C single bonds, alkenes a C=C double bond, alkynes a C≡C triple bond.

CₙH₂ₙ₊₂.

Addition of an electrophile across a double bond, e.g. HBr or Br₂ adding to an alkene.

Anti adds groups to opposite faces (e.g. Br₂); syn adds to the same face (e.g. hydrogenation).

A chiral compound rotates plane-polarized light; a racemic 50:50 mix shows no net rotation.

Assigned by Cahn-Ingold-Prelog priority: clockwise = R, counterclockwise = S (lowest priority pointing away).

Different spatial arrangements from rotation about single bonds (e.g. chair vs boat cyclohexane).

The chair conformation, with bulky groups in equatorial positions.

Aromatic rings undergo substitution (preserving aromaticity) rather than addition.

An organomagnesium compound (R–MgX) that acts as a strong nucleophile/carbon base.

Aldehydes are more reactive than ketones toward nucleophilic addition (less steric/electronic hindrance).

A carboxylic acid plus an alcohol (acid-catalyzed) forms an ester and water.

Each ring or π bond counts as one; calculated from the molecular formula to deduce structure.

Carboxylic acids (−COOH) — resonance stabilizes the carboxylate anion.

An object stays at rest or in uniform motion unless acted on by a net external force (inertia).

F = ma — net force equals mass times acceleration.

For every action there is an equal and opposite reaction.

A scalar has magnitude only (speed, mass); a vector has magnitude and direction (velocity, force).

Speed is a scalar (how fast); velocity is a vector (how fast and in what direction).

The rate of change of velocity: a = Δv/Δt (m/s²).

v = v₀ + at (final velocity from initial velocity and acceleration).

x = v₀t + ½at².

v² = v₀² + 2aΔx (no time needed).

About 9.8 m/s² downward near Earth's surface.

Horizontal and vertical motions are independent; horizontal velocity is constant, vertical accelerates at g.

R = v₀²·sin(2θ)/g; maximum range occurs at a launch angle of 45°.

p = mv — mass times velocity; it is conserved in an isolated system.

Impulse = FΔt = Δp (the change in momentum).

KE = ½mv².

PE = mgh (mass × gravity × height).

Energy is neither created nor destroyed; total mechanical energy is constant without friction.

W = F·d·cos θ (force times displacement times the cosine of the angle between them).

The rate of doing work: P = W/t (watts).

F = −kx — a spring's restoring force is proportional to its displacement.

T = 2π·√(L/g) — depends on length and gravity, not mass or amplitude.

T = 2π·√(m/k).

v = f·λ — speed equals frequency times wavelength.

f = 1/T — frequency is the inverse of the period.

V = IR — voltage equals current times resistance.

P = IV = I²R = V²/R (watts).

Series: R_total = R₁ + R₂ + …; parallel: 1/R_total = 1/R₁ + 1/R₂ + ….

F = k·q₁q₂/r² — the electrostatic force between two charges.

Forms a real, inverted image when the object is beyond the focal point; virtual/upright when closer.

Always forms a virtual, upright, reduced image.

A converging (convex) lens has positive focal length; a diverging (concave) lens has negative focal length.

1/f = 1/dₒ + 1/dᵢ (focal length from object and image distances).

The angle of incidence equals the angle of reflection (measured from the normal).

n₁·sin θ₁ = n₂·sin θ₂ — light bends toward the normal entering a denser medium.

n = c/v — the ratio of light's speed in vacuum to its speed in the medium (n ≥ 1).

ρ = m/V (mass per unit volume).

P = ρgh — pressure increases with depth, density, and gravity.

The buoyant force on a submerged object equals the weight of the fluid it displaces.

ΔU = Q − W — change in internal energy equals heat added minus work done by the system.

Q = mcΔT — heat equals mass × specific heat × temperature change.

a_c = v²/r, directed toward the center of the circular path.

E = hf = hc/λ — proportional to frequency (Planck's constant h).

τ = r·F·sin θ — the rotational effect of a force about a pivot.

The observed frequency rises as a source approaches and falls as it recedes.

Mass is the amount of matter (kg, constant); weight is the force of gravity on it (W = mg, varies).

Static friction resists starting motion (larger max); kinetic friction acts during sliding (usually smaller).

f = μN — coefficient of friction times the normal force.

Equal and opposite to the object's weight component perpendicular to the surface (N = mg on level ground).

Both conserve momentum; only an elastic collision also conserves kinetic energy.

In an isolated system, total momentum before a collision equals total momentum after.

The hertz (Hz) — one cycle per second.

The distance between successive crests (or troughs) of a wave.

A wave's energy is proportional to the square of its amplitude.

Transverse: oscillation ⊥ to travel (light); longitudinal: oscillation ∥ to travel (sound).

A real image forms where light actually converges (can be projected); a virtual image only appears to.

Occurs when light hits a less-dense medium beyond the critical angle and fully reflects.

−1.6 × 10⁻¹⁹ coulombs (the proton is +1.6 × 10⁻¹⁹ C).

The rate of flow of electric charge: I = Q/t (amperes).

Stores electric charge and energy in an electric field between two plates (Q = CV).

F = qvB·sin θ — maximum when velocity is perpendicular to the field.

Series: current is the same everywhere; parallel: voltage is the same across each branch.

K = °C + 273.15 (absolute zero is 0 K = −273.15 °C).

Q = mL — heat absorbed/released during a phase change at constant temperature.

The constant speed reached when drag force equals gravity, so net force (and acceleration) is zero.

Three passages on scientific topics, 50 items total in 60 minutes.

Answer ONLY from the text — no outside knowledge; bringing in your own facts is the #1 trap.

Asks for a directly stated fact; locate the exact line — don't rely on memory.

Asks the passage's overall point; pick the choice covering the WHOLE passage, not one detail.

Asks an unstated but supported conclusion; stay one short step from the text and reject added facts.

Asks the author's attitude or goal; most science passages are neutral and informational.

Asks a word's meaning AS USED; use the sentence's clue, not the dictionary's first definition.

Skim for structure and note where key facts live, then jump to the relevant lines for each question.

A true detail is too narrow to be the main idea — the main idea must cover the entire passage.

Choices with 'always,' 'only,' or 'never' are usually wrong unless the passage states them outright.

Treat Reading as finding information, not memorizing it — confirm every detail answer against the text.

About 72 seconds per item (50 items in 60 minutes) across three passages.

Asks you to apply the passage's idea to a new situation; the logic must come from the text.

Usually objective and informative — beware reading them as persuasive or emotional.

Find the choice that is FALSE or unsupported; the other three are stated or implied.

Many high scorers preview questions or map the passage first, then locate answers — pick a consistent method.

Return to the exact line in the passage; never answer a detail question from memory.

The test only credits what THIS passage says — a true real-world fact can still be the wrong answer.

Budget about 20 minutes per passage; don't let one hard passage eat another's time.

Check the first and last sentences of paragraphs and the overall structure of the passage.

(new − old) ÷ old × 100; always divide by the ORIGINAL value.

Cross-multiply: a/b = c/d means ad = bc.

x = (−b ± √(b² − 4ac)) ÷ 2a, for ax² + bx + c = 0.

a² + b² = c² for a right triangle (c is the hypotenuse).

Area = πr²; circumference = 2πr.

sin = opp/hyp, cos = adj/hyp, tan = opp/adj.

1 : √3 : 2 (opposite the 30°, 60°, 90° angles).

1 : 1 : √2.

Favorable outcomes ÷ total outcomes (a value from 0 to 1).

Independent AND → multiply; mutually exclusive OR → add.

Mean = average; median = middle value; mode = most frequent value.

m = (y₂ − y₁) ÷ (x₂ − x₁) — rise over run.

y = mx + b, where m is the slope and b is the y-intercept.

xᵃ⁺ᵇ — add exponents when multiplying like bases.

(xᵃ)ᵇ = xᵃᵇ — multiply the exponents.

x⁻ⁿ = 1/xⁿ.

V = πr²h.

V = length × width × height.

distance = rate × time (d = rt).

Sum of the values ÷ n (the count of values).

PEMDAS: Parentheses, Exponents, Multiplication/Division, Addition/Subtraction (left to right).

Divide by 100 (move the decimal two places left): 25% = 0.25.

A = ½ × base × height.

180°; for an n-sided polygon it is (n − 2) × 180°.

If a length scales by k, area scales by k² and volume by k³.

Permutations count ordered arrangements; combinations count unordered selections (order doesn't matter).

n! = n × (n−1) × … × 1; for example 4! = 24.

Use substitution or elimination to find the values that satisfy both equations.

|x| is the distance from zero, always nonnegative: |−3| = 3.

Direct: y = kx (rise together); inverse: y = k/x (one rises as the other falls).

Divide both terms by their greatest common factor: 8:12 → 2:3.

The median resists outliers; the mean is pulled toward extreme values.

The largest value minus the smallest value.

Interest is earned on principal plus accumulated interest: A = P(1 + r)ᵗ.

P(not A) = 1 − P(A).

Divide and multiply by 100: 3/4 = 0.75 = 75%.

A measure of how spread out data values are around the mean.

Reverse the inequality sign when multiplying or dividing both sides by a negative number.