IMAT key terms

A deductive argument of two premises and a conclusion where the conclusion must be true whenever both premises are true, because of the argument's form rather than its content.

The basic parts of an argument: premises are the statements offered as reasons, and the conclusion is the claim they are meant to support. Indicator words such as 'therefore' or 'because' help identify each.

An unstated premise that a argument needs in order for its conclusion to follow. Spotting it means asking what extra claim the author must believe but has left unsaid.

The logically equivalent form of a conditional statement. 'If P then Q' becomes 'if not Q then not P'. Unlike the converse, the contrapositive always preserves truth.

A necessary condition must hold for something to happen; a sufficient condition guarantees it. 'Only if' marks a necessary condition, while 'if' alone marks a sufficient one.

A question type asking which option makes a stated conclusion less likely to follow from its premises, usually by offering an alternative explanation or by showing a hidden assumption is false.

A common reasoning flaw in which two things occurring together is treated as proof that one causes the other. A hidden third factor or reverse causation may explain the link instead.

In an experiment, the comparison group that does not receive the treatment under test. It isolates the effect of the variable being studied from other influences.

The independent variable is the factor deliberately changed or selected by the researcher; the dependent variable is the measured outcome that may respond to it.

A result is statistically significant when it is unlikely to have arisen by chance alone, conventionally below a 5% probability. It does not by itself prove the effect is large or important.

A distortion that occurs when the group studied is not representative of the population about which conclusions are drawn, for example because volunteers differ from non-volunteers.

A conclusion drawn from evidence rather than stated directly. In reading comprehension, inference questions ask what the passage implies but does not say outright.

The central claim or point that a passage is organised around, as distinct from supporting details. It usually answers the question of why the text was written.

The attitude a writer conveys towards the subject, such as critical, neutral, ironic or enthusiastic, signalled by word choice and sentence structure rather than stated explicitly.

The way sentences and paragraphs are linked so a text reads as a single whole, achieved through pronouns, repeated terms, conjunctions and logical connectors such as 'however' or 'therefore'.

The phospholipid bilayer surrounding a cell that controls which substances enter and leave. Its embedded proteins act as channels, pumps and receptors.

Diffusion is the net movement of particles from high to low concentration; osmosis is the diffusion of water across a selectively permeable membrane from lower to higher solute concentration.

A protein that speeds up a specific biochemical reaction by lowering its activation energy. Its active site binds a particular substrate, and shape changes can denature it.

Adenosine triphosphate, the universal energy currency of cells. Energy released when its terminal phosphate bond is broken drives processes such as active transport and muscle contraction.

The breakdown of glucose to release energy, beginning with glycolysis and continuing in the mitochondria. Aerobic respiration yields far more ATP than anaerobic fermentation.

The process by which plants, algae and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen, occurring in chloroplasts.

Mitosis produces two genetically identical daughter cells for growth and repair. Meiosis produces four genetically varied gametes with half the chromosome number, enabling sexual reproduction.

An allele is one variant of a gene; a genotype is the combination of alleles an organism carries. The phenotype is the observable trait produced by that genotype and its environment.

A dominant allele is expressed even when only one copy is present; a recessive allele is expressed only when two copies are present, as in homozygous recessive individuals.

A grid used to predict the possible genotypes of offspring from the alleles of two parents, showing probabilities such as a 3:1 ratio in a monohybrid cross.

The exchange of corresponding chromosome segments between homologous chromosomes during meiosis, which creates new allele combinations and increases genetic variation in gametes.

The maintenance of a stable internal environment, such as constant body temperature or blood glucose, through negative feedback mechanisms involving sensors and effectors.

A chemical messenger secreted by an endocrine gland into the blood, acting on target cells with matching receptors. Insulin and adrenaline are examples.

One mole contains 6.022 × 10^23 particles, the Avogadro constant. It links the mass of a substance in grams to the number of particles it contains.

The mass of one mole of a substance in grams per mole, numerically equal to its relative molecular mass. It converts between mass and amount in moles.

The calculation of quantities of reactants and products from a balanced chemical equation, using the mole ratios shown by the coefficients.

The reactant that is used up first in a reaction and therefore determines the maximum amount of product formed; the other reactants are said to be in excess.

A logarithmic measure of hydrogen ion concentration: pH equals the negative logarithm of that concentration. Values below 7 are acidic and above 7 are basic.

An acid donates protons and a base accepts them (Brønsted–Lowry). In water, acids release hydrogen ions and bases release hydroxide ions or accept protons.

A solution that resists changes in pH when small amounts of acid or base are added, usually a mixture of a weak acid and its conjugate base.

Oxidation is loss of electrons and reduction is gain of electrons. In a redox reaction the two occur together, and oxidation numbers change accordingly.

The use of electrical energy to drive a non-spontaneous chemical reaction in an electrolyte, producing substances at the electrodes according to the ions present.

The equation pV = nRT relating pressure, volume, amount in moles and absolute temperature of an ideal gas, where R is the gas constant.

The net force on an object equals its mass times its acceleration (F = ma). It explains how forces change motion and underlies weight as mg.

For every action force there is an equal and opposite reaction force acting on a different body. The two forces never cancel because they act on different objects.

A contact force opposing relative motion or the tendency to move between surfaces. Static friction prevents sliding up to a maximum; kinetic friction acts during sliding.

Work is force times displacement in the direction of the force, measured in joules. The work–energy theorem states that net work equals the change in kinetic energy.

Energy cannot be created or destroyed, only transferred or transformed between forms. In a closed system the total energy remains constant.

For a conductor at constant temperature, current is directly proportional to potential difference (V = IR), where resistance is measured in ohms.

The rate at which electrical energy is transferred, given by P = VI or P = I²R. It is measured in watts and links current, voltage and resistance.

Force acting perpendicular to a surface divided by the area of that surface, measured in pascals. In fluids it increases with depth and depends on density.

The instantaneous rate of change of a function, equal to the gradient of its tangent line. It is used to find maxima, minima and rates in physics problems.

The limit of a sum of areas under a curve, giving accumulated change or total quantity. Definite integrals compute areas and distances from velocity.

A number between 0 and 1 expressing how likely an event is. For equally likely outcomes it equals favourable outcomes divided by total outcomes.

Counting methods for arrangements and selections, including permutations where order matters and combinations where it does not, often used in probability calculations.

A function of the form f(x) = a^x, where the constant base is raised to a variable power. It models growth, decay and radioactive change.

The inverse of exponentiation: log base b of x is the power to which b must be raised to give x. It converts multiplication into addition and underlies pH.

The study of ratios in right triangles and of periodic functions. Sine, cosine and tangent relate angles to side lengths and describe waves and circular motion.

A quantity with both magnitude and direction, such as displacement or force, represented by an arrow. Vectors add by components or by the parallelogram rule.