USJ Medical Sciences Concours - Medicine, Dental Medicine & Pharmacy key terms

The set of physiological adjustments that keep internal conditions-such as temperature, blood glucose, and pH-within narrow ranges compatible with cell function, despite changes in the external environment.

A control mechanism in which a change in a regulated variable triggers responses that reduce that change, restoring the variable toward its set point; common in hormone and temperature regulation.

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 differences in water potential.

A protein, or occasionally RNA, that speeds up a specific biochemical reaction by lowering its activation energy without being consumed, and whose activity depends on temperature, pH, and substrate concentration.

Adenosine triphosphate, the cell's main energy-carrying molecule; hydrolysis of its terminal phosphate bond releases energy that powers transport, synthesis, and mechanical work.

Cell division that produces two genetically identical daughter cells from one parent cell, used for growth, tissue repair, and asexual reproduction in eukaryotes.

A specialized cell division in germ cells that halves the chromosome number and creates genetic variation through crossing over and independent assortment, producing gametes for sexual reproduction.

One of the alternative versions of a gene at a given chromosomal locus; different alleles may produce different traits, and an individual normally inherits one from each parent.

The particular combination of alleles an individual carries for one or more genes, which interacts with environmental factors to influence observable characteristics.

The process in which RNA polymerase builds an RNA copy from a DNA template, producing messenger RNA or other functional RNAs that carry genetic information outward from the nucleus.

A rapid, temporary change in a neuron's membrane voltage caused by ion channels opening and closing, used to transmit electrical signals along axons and to trigger neurotransmitter release.

The amount of substance containing Avogadro's number (about 6.02×10^23) of particles; it links particle counts to measurable mass using molar mass.

A concentration unit equal to moles of solute divided by liters of solution; it is widely used to prepare laboratory solutions and to calculate reaction quantities.

A chemical bond formed when two atoms share one or more pairs of electrons; it is typically strong and determines molecular shape and stability.

A relatively weak attraction between a hydrogen atom bonded to oxygen, nitrogen, or fluorine and a nearby electronegative atom; it stabilizes water's properties and DNA base pairing.

A logarithmic scale from 0 to 14 that expresses the concentration of hydrogen ions in a solution; lower values are acidic and higher values are basic.

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

A chemical change in which a substance loses electrons, or increases its oxidation state; it is always accompanied by reduction of another substance in a redox reaction.

A specific cluster of atoms within an organic molecule, such as a hydroxyl, carboxyl, or amino group, that gives the molecule characteristic chemical properties and reactivity.

The relationship stating that the net force on an object equals its mass times its acceleration (F = ma); it predicts how forces change motion.

Force exerted perpendicularly per unit area on a surface, measured in pascals; in fluids it increases with depth and affects blood flow and breathing.

A measure of a fluid's resistance to flow, caused by internal friction between fluid layers; higher viscosity means thicker flow, as in blood compared with water.

The relationship stating that current through a conductor equals voltage divided by resistance (I = V/R) when temperature and other conditions remain constant.

The distance between two consecutive corresponding points on a wave, such as crest to crest; it relates to frequency and wave speed by v = fλ.

The bending of a wave as it passes from one medium into another where its speed changes; it explains lenses, prisms, and the focusing of light in the eye.

A rule that assigns exactly one output value to each input value from a specified set; graphs, formulas, and tables can represent functions.

A number between 0 and 1 expressing how likely an event is, calculated from equally likely outcomes or estimated from data and long-run frequencies.

The probability that an event occurs given that another event has already occurred, written P(A|B) and equal to P(A and B) divided by P(B).

The arithmetic average of a set of values, found by adding all values and dividing by the number of values; it is sensitive to extreme observations.

A measure of how spread out values are around their mean; a small value means data cluster closely, while a large value means greater variability.

The exponent to which a base must be raised to produce a given number; for example, log base 10 of 1000 is 3, useful for pH and exponential data.

A testable, specific explanation or prediction about a relationship between variables, stated before data collection so that observations can support or refute it.

A study in which researchers manipulate one independent variable while keeping other relevant conditions constant, allowing a fair test of cause and effect.

An unmeasured or uncontrolled factor that is associated with both the supposed cause and the outcome, creating a misleading association that can distort causal conclusions.

A statistical relationship in which two variables tend to change together; correlation alone does not establish that one variable causes the other.

The proportion of people who truly have a condition and are correctly identified by a test as positive; high sensitivity means few false negatives.

The proportion of people who truly do not have a condition and are correctly identified by a test as negative; high specificity means few false positives.

The central point or overall message that a reading passage conveys; it is broader than a supporting detail and is often stated in the introduction or conclusion.

A conclusion drawn from evidence and reasoning rather than direct statement; readers combine textual clues with background knowledge to infer unstated meanings.

The attitude or emotional quality conveyed by a writer's word choices and sentence style, such as neutral, critical, cautious, or enthusiastic.