Mock UPCAT 3 – Key Science Vocabulary

A comprehensive set of vocabulary flashcards covering physics, chemistry, biology, and Earth-science concepts discussed in the Mock UPCAT 3 explanations.

Humidity

The amount of water vapor present in the air at a given time.

Convection

Heat transfer through bulk movement of a fluid, driven by density differences.

Convection Current

A circulating flow in a fluid where warmer, less-dense regions rise and cooler, denser regions sink.

Pressure Gradient (Air)

The change in atmospheric pressure that causes air to move from high- to low-pressure areas.

Terminal Velocity

The constant speed reached by a falling object when air resistance balances its weight.

Visible Spectrum

The seven colors (ROYGBIV) produced when white light is refracted through a prism or similar medium.

Photosynthesis

The process by which green plants convert light energy, CO₂, and water into glucose and oxygen.

Green Light Effect on Plants

Green wavelengths are reflected by chlorophyll; under only green light, photosynthesis is greatly limited.

Pulmonary Circulation

Blood flow pathway from right ventricle to lungs and back to left atrium.

Systemic Circulation

Blood flow pathway from left ventricle through the aorta to the rest of the body and back to the heart.

Respiratory Pathway

Air route: nasal cavity → pharynx → larynx → trachea → bronchi → bronchioles → alveoli.

Angiosperm

A flowering plant that produces seeds enclosed within a fruit.

Monocot

An angiosperm with one cotyledon, parallel venation, floral parts in 3’s, and scattered vascular bundles.

Dicot

An angiosperm with two cotyledons, netted venation, floral parts in 4’s or 5’s, and vascular bundles in rings.

Prokaryote

A unicellular organism lacking a true nucleus and membrane-bound organelles (e.g., bacteria, archaea).

Virus

A non-living infectious agent consisting of nucleic acid wrapped in a protein capsid; replicates only inside host cells.

Autotroph

An organism that produces its own food from inorganic substances (e.g., plants, algae).

First-Order Consumer

An herbivore that eats autotrophs in a food chain.

Detritivore

An organism that feeds on dead organic matter (e.g., molds, earthworms).

Second-Order Consumer

A carnivore or omnivore that eats herbivores.

Regeneration (Biology)

Ability of an organism to regrow lost body parts; extreme in planarians.

Adaptation

A heritable trait that improves an organism’s survival or reproduction in its environment.

Spermatogenesis

The meiotic process that forms four haploid sperm from one diploid spermatogonium.

Genotype

The genetic makeup (allele combination) of an organism for a specific trait.

Phenotype

The observable traits resulting from genotype and environment.

Law of Independent Assortment

Mendelian principle that alleles of different genes segregate independently during gamete formation.

Transcription

Synthesis of complementary RNA from a DNA template.

Dominant Allele

An allele that expresses its phenotype even in the presence of a recessive allele.

Recessive Allele

An allele expressed phenotypically only when homozygous.

Free Earlobes

A dominant human trait symbolized by allele X; attached earlobes are recessive (x).

Cell Wall

A rigid outer structure found in plants, fungi, and many prokaryotes, but absent in animal cells.

Mitochondrion

The eukaryotic organelle where aerobic respiration and ATP production occur.

Small Intestine (Function)

Digestive organ that completes chemical digestion and absorbs nutrients into the bloodstream.

Tibial Nerve

A mixed (motor & sensory) nerve supplying the lower leg and foot; block causes loss of movement and sensation below it.

Cretaceous–Paleogene Extinction

Event ~66 million years ago that eliminated non-avian dinosaurs, long before humans evolved.

Insect

An arthropod with 6 legs and three body segments; e.g., ants, beetles, butterflies.

Arachnid

An eight-legged arthropod such as spiders, scorpions, or ticks.

Paleozoic Era

Oldest of the three major Phanerozoic eras, preceding the Mesozoic and Cenozoic.

Mesosphere (Atmosphere)

The atmospheric layer above the stratosphere; coldest layer of Earth’s atmosphere.

Troposphere

Lowest atmospheric layer where weather processes and most water vapor occur.

Ionosphere

Ion-rich region of the thermosphere that reflects radio waves back to Earth.

Mid-Ocean Ridge

An underwater mountain chain formed by divergent tectonic plates and upwelling magma.

Lunar Phases

Regular changes in the Moon’s appearance due to its orbit around Earth and changing illumination.

Astronomical Unit (AU)

Average Earth–Sun distance (~150 million km).

Uranus (Axial Tilt)

Planet whose rotational axis lies almost in its orbital plane, causing it to roll like a wheel.

Mercury (Element)

A metallic element, liquid at room temperature, used in thermometers and barometers (symbol Hg).

Carbon Dioxide

A covalent compound of one carbon and two oxygen atoms (CO₂).

Mixture

A physical blend of substances that retain their individual properties (e.g., milk).

Chemical Change Indicator: Color Change

A visible shift in color signaling a chemical reaction, such as rust formation.

Chemical Change Indicator: Gas Evolution

Release of a gas during a reaction, e.g., CO₂ fizzing from vinegar and baking soda.

Chemical Change Indicator: Precipitate Formation

Creation of an insoluble solid from solution, e.g., AgCl from AgNO₃ and NaCl.

Selenium

A nonmetallic element used in metallurgy and electronics (symbol Se).

Ionic Compound Formula

Written by balancing total positive and negative charges, e.g., CaCl₂.

Avogadro’s Number

6.02 × 10²³ particles per mole; converts between atoms/molecules and moles.

Gas Constant (R)

Proportionality constant in the ideal gas law; value = 8.314 J·mol⁻¹·K⁻¹.

Organic Compound

A molecule containing carbon bonded to hydrogen, often with O, N, or other elements.

Molecule

The smallest unit of a compound that retains its chemical properties.

Trigonal Pyramidal

Molecular shape for AX₃E (e.g., NH₃) with three bonds and one lone pair on the central atom.

Atomic Radius Trend

Decreases left-to-right across a period due to increasing nuclear charge.

Electron Affinity Trend

Generally increases (more negative) left-to-right across a period as atoms more readily gain electrons.

Limiting Reactant

Reactant that is completely consumed first, limiting the amount of product formed.

Redox Reaction

Chemical reaction involving simultaneous oxidation and reduction of species.

Partial Pressure

The individual pressure exerted by a gas in a mixture proportional to its mole fraction.

Average Speed

Total distance divided by total time traveled.

Weight

Force of gravity on an object; equal to mass × gravitational acceleration.

Sound Intensity and Amplitude

Plucking strings harder increases vibration amplitude, thus increasing sound energy.

Short Circuit

An electrical fault where current bypasses intended path due to very low resistance, causing excessive current.

Series Voltage

Voltages of sources in series add algebraically to give total voltage.

Series Resistance

Total resistance is the sum of resistances connected in series.

Parallel Resistance

Total resistance is found from the reciprocal of the sum of reciprocals of individual resistances.

Wavelength

Distance between two consecutive points in the same phase on a wave (e.g., crest to crest).

Work (Physics)

Product of force and displacement in the direction of the force; no displacement ⇒ no work.