Cambodia Health Entrance Exam key terms

The body's ability to keep internal conditions such as temperature, pH, and blood glucose steady despite outside changes, mainly through feedback loops controlled by the nervous and endocrine systems.

The movement of water across a semi-permeable membrane from a region of lower solute concentration to a region of higher solute concentration, a passive process that does not require cellular energy.

The net movement of particles from an area of higher concentration to an area of lower concentration until they are evenly spread, driven by random molecular motion and requiring no energy input.

Movement of ions or molecules across a cell membrane against their concentration gradient using carrier proteins and energy from ATP, for example the sodium-potassium pump in nerve cells.

A protein that speeds up a specific biochemical reaction by lowering its activation energy; its active site fits only particular substrates and can be denatured by heat or extreme pH.

The molecule on which an enzyme acts; it binds temporarily to the enzyme's active site to form an enzyme-substrate complex before being converted into products.

Cell division producing two genetically identical daughter cells with the same chromosome number as the parent, responsible for growth, repair, and replacement of body tissues.

A two-stage reduction division in germ cells that halves the chromosome number and creates four genetically varied gametes, providing the basis of sexual reproduction and genetic variation.

A thread-like structure of DNA wrapped around histone proteins, carrying genes in a linear sequence; human body cells normally contain 46 chromosomes arranged in 23 pairs.

Adenosine triphosphate, the universal energy currency of cells; breaking its terminal phosphate bond releases energy used for muscle contraction, transport, and synthesis reactions.

The controlled release of energy from glucose inside cells, either with oxygen (aerobic) producing carbon dioxide and water, or without oxygen (anaerobic) producing lactate or ethanol.

The amount of substance containing 6.02 x 10^23 particles (Avogadro's number); it links the mass of a sample in grams to the number of atoms or molecules present.

The mass of one mole of a substance in grams per mole, numerically equal to its relative molecular mass; used to convert between mass and moles in calculations.

The constant 6.02 x 10^23, giving the number of particles in one mole of any substance; it allows chemists to count atoms and molecules by weighing samples.

A logarithmic scale from 0 to 14 measuring hydrogen ion concentration; values below 7 are acidic, 7 is neutral, and above 7 is alkaline, each unit representing a tenfold change.

A substance that donates protons (hydrogen ions) to another species in solution, turning blue litmus red and reacting with bases to form salt and water.

A substance that accepts protons or releases hydroxide ions in solution, turning red litmus blue and neutralising acids; common examples include sodium hydroxide and ammonia.

Loss of electrons by a species, often observed as gain of oxygen or loss of hydrogen; it always occurs together with reduction in a redox reaction.

Gain of electrons by a species, often seen as loss of oxygen or gain of hydrogen; the oxidising agent is itself reduced during the reaction.

A chemical bond formed when two atoms share one or more pairs of electrons, typically between non-metals, producing molecules such as water and carbon dioxide.

The electrostatic attraction between oppositely charged ions formed when one atom transfers electrons to another, usually between a metal and a non-metal, as in sodium chloride.

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass, expressed as F = ma.

For every action force there is an equal and opposite reaction force acting on a different body; the two forces are equal in size and opposite in direction.

The product of an object's mass and velocity, a vector quantity measured in kilogram metres per second; total momentum is conserved in a closed system.

The current through a conductor is directly proportional to the potential difference across it, provided temperature stays constant; written as V = IR.

The opposition a component offers to the flow of electric current, measured in ohms; it depends on material, length, cross-sectional area, and temperature.

The energy transferred when a force moves an object through a distance in the direction of the force, calculated as force multiplied by displacement and measured in joules.

The rate at which work is done or energy is transferred, equal to work divided by time and measured in watts, where one watt equals one joule per second.

The energy an object possesses because of its motion, calculated as one half of mass times velocity squared; doubling speed quadruples kinetic energy.

In a right-angled triangle, the square of the hypotenuse equals the sum of the squares of the other two sides, written a squared plus b squared equals c squared.

A ratio of two sides of a right triangle defined by an acute angle, such as sine (opposite over hypotenuse), cosine (adjacent over hypotenuse), and tangent (opposite over adjacent).

An equation of the form ax squared plus bx plus c equals zero with a not zero; its solutions can be found by factorising, completing the square, or the quadratic formula.

The expression b squared minus 4ac in the quadratic formula; its sign tells whether the equation has two real roots, one repeated root, or no real roots.

A number between 0 and 1 expressing how likely an event is, calculated for equally likely outcomes as the number of favourable outcomes divided by total outcomes.

An arrangement of objects in which order matters; the number of ways to arrange r objects chosen from n distinct objects is n factorial divided by (n minus r) factorial.

A form of deductive reasoning with two premises leading to a conclusion, for example: all A are B, all B are C, therefore all A are C.

Drawing valid conclusions from given statements by applying rules of inference rather than prior beliefs, including detecting contradictions and evaluating necessary versus sufficient conditions.

The body of writing in the Khmer language, including classical verse forms such as the Reamker, the Chbap moral codes, modern novels, and contemporary poetry.

The Cambodian epic based on the Ramayana, adapted into Khmer verse and performed in classical dance and shadow theatre; it explores duty, loyalty, and the triumph of good.