Comprehensive General Science Vocabulary

Vocabulary flashcards covering key terms across general science, biology, chemistry, ecology, physics, and related disciplines.

Science

Systematic knowledge of natural phenomena obtained and tested through the scientific method.

Scientific Method

A seven-step process: observe, collect data, formulate hypothesis, test, analyze, conclude, and communicate.

Hypothesis

Testable assumption or idea validated through experimentation.

Independent Variable (IV)

Factor deliberately changed to observe its effect on the dependent variable.

Dependent Variable (DV)

Measured outcome affected by changes in the independent variable.

Scientific Law

Statement based on repeated observations that describes a natural phenomenon.

Scientific Theory

Well-tested, widely accepted explanation of natural facts and predictions.

Model (Scientific)

Representation that helps visualize objects or events not directly observable.

Kilogram (kg)

SI base unit of mass.

Meter (m)

SI base unit of length.

Second (s)

SI base unit of time.

Mole (mol)

SI base unit for amount of substance.

Kelvin (K)

SI base unit of temperature.

Ampere (A)

SI base unit of electric current.

Candela (cd)

SI base unit of luminous intensity.

Lithosphere

Solid, outer layer of Earth’s crust and upper mantle.

Hydrosphere

All water on, under, and above Earth’s surface.

Atmosphere

Layer of gases surrounding Earth, held by gravity.

Biosphere

Regions of Earth where life exists.

Igneous Rock

Rock formed from cooled magma; e.g., granite, basalt.

Sedimentary Rock

Rock made from pre-existing materials or remains; e.g., limestone.

Metamorphic Rock

Rock altered by heat, pressure, or chemical processes; e.g., marble.

Weathering

Breakdown of rocks by water, temperature changes, or biology.

Erosion

Transport of earth materials by wind, water, or ice.

Lithification

Conversion of sediments into solid rock by compaction or cementation.

Meteorology

Study of atmospheric processes and weather forecasting.

Weather

Short-term state of atmosphere (temperature, wind, humidity, etc.).

Climate

Long-term (≥30 years) average weather conditions of a region.

Troposphere

Lowest atmospheric layer, containing ~75 % of mass, up to 10–15 km.

Stratosphere

Atmospheric layer above troposphere, 15–50 km, warmer at top.

Mesosphere

50–80 km layer where temperature decreases with altitude.

Thermosphere

80 km to space; very high temperatures due to solar energy.

Exosphere

Outermost, least-dense atmospheric layer; temperature >2000 °C.

Ecology

Branch of biology studying organism interactions with environment.

Biotic Factor

Living component of an environment.

Abiotic Factor

Non-living environmental component essential to life.

Population (Ecology)

All individuals of one species in a given area.

Community (Ecology)

Interacting populations of different species in an area.

Ecosystem

Biotic community plus abiotic environment functioning as a unit.

Biome

Large geographic region classified by characteristic flora and fauna.

Nebular Theory

Model describing solar system formation from a rotating gas-dust cloud 4.5 billion years ago.

Ptolemaic Theory

Ancient geocentric model with Earth at the universe’s center.

Copernican Theory

Heliocentric model placing Sun at center, published 1543.

Asteroid

Rocky object, meters to hundreds of kilometers, mostly in belt between Mars and Jupiter.

Meteoroid

Small space rock or iron chunk traveling through space.

Comet

Ice-dust body with glowing coma and tail when near Sun.

Solar Eclipse

Moon passes between Earth and Sun, blocking sunlight.

Lunar Eclipse

Full Moon moves into Earth’s shadow (umbra).

Biology

Science of life and living organisms.

Cell

Basic unit of life; may exist singly or as part of multicellular organism.

Amyloplast

Plant organelle storing starch, common in tubers.

Cell Wall

Rigid cellulose layer outside plant cell membrane providing support.

Cell Membrane

Semi-permeable phospholipid bilayer regulating substance entry/exit.

Centrosome

Organelle near nucleus where microtubules originate; contains centrioles.

Chloroplast

Disc-shaped organelle with chlorophyll; site of photosynthesis.

Chlorophyll

Green pigment converting light energy to chemical energy in photosynthesis.

Cytoplasm

Gel-like interior of cell surrounding organelles.

Golgi Body

Stacked sacs that modify, package, and ship proteins/lipids.

Mitochondrion

Double-membrane organelle generating ATP; “powerhouse of the cell.”

Nuclear Membrane

Envelope surrounding nucleus, separating it from cytoplasm.

Nucleolus

Dense region in nucleus where rRNA is synthesized.

Ribosome

RNA-protein complex where protein synthesis occurs.

Rough Endoplasmic Reticulum

ER studded with ribosomes; synthesizes and transports proteins.

Smooth Endoplasmic Reticulum

ER lacking ribosomes; synthesizes lipids, detoxifies, stores ions.

Vacuole

Large fluid-filled sac in plants for storage and turgor maintenance.

Lysosome

Animal-cell vesicle containing digestive enzymes for intracellular digestion.

Cell Theory

1) All organisms consist of cells; 2) cells are basic units of structure and function; 3) cells arise from pre-existing cells.

Carbohydrate

Biomolecule of C, H, O; monomer = monosaccharide; energy source.

Lipid

Hydrophobic biomolecule from fatty acids; includes oils, waxes, cholesterol.

Protein

Polymer of amino acids; performs structural and enzymatic functions.

Nucleic Acid

Polymer of nucleotides storing genetic information (DNA, RNA).

Prokaryotic Cell

Simple cell lacking nucleus and membrane-bound organelles (e.g., bacteria).

Eukaryotic Cell

Cell with nucleus and organelles; includes fungi, plants, animals.

Passive Transport

Movement across membrane down concentration gradient without energy.

Active Transport

Energy-requiring movement of substances against concentration gradient.

Diffusion

Net movement of molecules from high to low concentration.

Osmosis

Diffusion of solvent through semipermeable membrane from dilute to concentrated solution.

Mitosis

Eukaryotic cell division producing two genetically identical diploid cells.

Meiosis

Cell division producing four genetically unique haploid gametes.

Parenchyma Cell

Living plant cell with thin walls for photosynthesis and storage.

Collenchyma Cell

Elongated plant cell with thickened corners providing flexible support.

Sclerenchyma Cell

Thick-walled lignified plant cell providing strength; often dead at maturity.

Meristematic Tissue

Region of actively dividing plant cells enabling growth.

Epidermis (Plant)

Outer protective layer of cells with waxy cuticle.

Periderm

Protective outer covering replacing epidermis in woody plants.

Xylem

Vascular tissue transporting water and minerals from roots upward.

Phloem

Vascular tissue transporting sugars from leaves to rest of plant.

Root

Plant organ anchoring and absorbing water/nutrients.

Stem

Supportive plant axis bearing leaves and conduits.

Leaf

Photosynthetic organ typically flat and green.

Flower

Reproductive structure of angiosperms bearing stamens and carpels.

Fruit

Mature ovary containing seeds, often edible.

Photosynthesis

Conversion of CO₂ and H₂O into glucose and O₂ using light energy.

Transpiration

Loss of water vapor from plant surfaces, mainly leaves.

Respiration (Plants)

Metabolic process converting stored carbohydrates into usable energy.

Taxonomy

Science of naming and classifying organisms into hierarchical groups.

Dominant Allele

Gene variant expressed in phenotype when heterozygous.

Recessive Allele

Allele masked by dominant in heterozygote; expressed when homozygous.

Law of Segregation

Mendelian principle: alleles separate during gamete formation.

Law of Independent Assortment

Genes for different traits segregate independently during meiosis.