DAT key terms

The body's tendency to keep internal conditions such as temperature, pH, and blood glucose within a narrow, stable range despite outside changes, achieved through coordinated sensing and corrective responses.

A control cycle in which a deviation from a set point triggers a response that reduces that deviation, such as insulin lowering high blood glucose and returning the system toward normal.

The net movement of water across a selectively permeable membrane from a region of lower solute concentration to one of higher solute concentration, driven by the difference in water potential.

The quantitative description of how reaction rate rises with substrate concentration and levels off at a maximum velocity, characterized by Km, the substrate level giving half of that maximum rate.

The cytoplasmic pathway that splits one glucose molecule into two pyruvate molecules, producing a small net yield of ATP and NADH without requiring oxygen.

The semi-conservative process in which each parental strand serves as a template for a new complementary strand, yielding two daughter double helices identical to the original.

The synthesis of an RNA copy from a DNA template, carried out by RNA polymerase, which produces messenger RNA that can later be translated into protein.

Mendel's principle that the two alleles of a gene separate during gamete formation, so each gamete carries only one allele for that gene.

The process by which heritable traits that improve survival or reproduction become more common in a population over generations because their bearers leave more offspring.

When a system at equilibrium is disturbed by a change in concentration, pressure, or temperature, the system shifts in the direction that partially counteracts that change.

pH measures hydrogen ion concentration on a logarithmic scale; pKa is the pH at which an acid is half dissociated, indicating how readily it gives up a proton.

A solution containing a weak acid and its conjugate base that resists large pH changes when small amounts of strong acid or base are added.

The relationship PV = nRT linking pressure, volume, moles of gas, and absolute temperature, valid as a good approximation for gases at low pressure and moderate temperature.

A thermodynamic quantity whose change determines spontaneity at constant temperature and pressure; a negative change means the reaction proceeds spontaneously, a positive one does not.

A coupled reaction in which one species loses electrons (is oxidized) while another gains them (is reduced), often transferring energy through carriers such as NADH.

The property of a molecule that cannot be superimposed on its mirror image, usually due to a carbon bearing four different groups, giving rise to nonidentical enantiomers.

One of two or more compounds sharing the same molecular formula but differing in how atoms are connected or arranged in space, which can give them different properties.

A specific cluster of atoms within an organic molecule, such as hydroxyl, carbonyl, or carboxyl, that largely determines the molecule's chemical behavior and reactivity.

A nucleophile is an electron-rich species that donates a pair of electrons to form a bond; an electrophile is electron-poor and accepts that pair during a reaction.

The extra stability of a planar, cyclic, fully conjugated system whose delocalized electrons number 4n+2, as in benzene, making it unusually unreactive toward addition.

A method of representing a three-dimensional object by separate flat views, such as top, front, and side, each showing true shape along one axis of sight.

The perceptual task of judging which of several drawn angles is largest or smallest when the angles differ only slightly and no reference markings are provided.

A paper-folding task in which a folded sheet is punched and the candidate must determine the pattern of holes that appears when the sheet is fully unfolded.

A task requiring the tally of painted or unpainted cube faces in a stacked block structure, inferring hidden supporting cubes from the visible arrangement.

Imagining how a two- or three-dimensional shape would look after being turned in space, used to decide whether two figures are the same object or mirror images.

The tendency to perceive an object's true shape as unchanged even when it is rotated, tilted, or viewed from an angle that distorts the retinal image.

The perceptual act of distinguishing a target shape from surrounding background patterns that may share edges, shading, or texture with it.

The central claim or point that a passage as a whole is developed to support, broad enough to cover the whole text but narrow enough to exclude minor details.

A specific fact, example, or statistic in a passage that explains, illustrates, or provides evidence for the main idea rather than stating it directly.

A conclusion that follows necessarily from statements in a passage without being stated outright, requiring the reader to combine given information with logic.

The attitude a writer conveys toward the subject through word choice and phrasing, such as critical, enthusiastic, neutral, or ironic.

A reading strategy of briefly noting each paragraph's function and key claim so that questions about specific content can be answered by returning to the right location quickly.

An answer choice that sounds plausible or repeats passage wording but is wrong because it distorts, overstates, or only partially matches what the text says.

The difference between a new and an original value divided by the original value, then multiplied by 100, expressing increase or decrease relative to the starting amount.

A ratio compares two quantities by division, and a proportion states that two ratios are equal, allowing an unknown value to be found by cross-multiplication.

The likelihood of an event, computed as the number of favorable outcomes divided by the total number of equally likely outcomes, ranging from zero to one.

Permutations count ordered arrangements of selected items, while combinations count unordered selections; the distinction matters whenever position or sequence changes the outcome.

A technique for converting units by multiplying by conversion factors written as fractions so that unwanted units cancel and only the desired unit remains.

Slope measures a line's steepness as the change in the vertical variable divided by the change in the horizontal variable; a linear equation graphs as a straight line.

The mean is the arithmetic average of a data set, while the median is the middle value when data are ordered; the median resists distortion by extreme values.