Comprehensive Licensure Examination for Teachers (LET) Science Majorship Study Guide

A comprehensive vocabulary review of core scientific terms, experimental methods, and physical laws featured in the actual Licensure Examination for Teachers (LET) Science Majorship.

Gene

The fundamental physical and functional unit of heredity passed from parents to offspring.

Global Positioning System (GPS)

A satellite-based radio navigation system utilized to pinpoint geographic positions anywhere on Earth.

Cytokinesis

The process of physical cytoplasmic division in eukaryotic cells that enables organismal growth and the replacement of worn-out cells.

Lipids

A major class of biomolecules comprising fats and oils, structurally characterized by saturated or unsaturated fatty acids.

Biological Organization Hierarchy

The structural ordering of matter in living organisms arranged from smallest to largest: Atom $\rightarrow$ Molecule $\rightarrow$ Cell $\rightarrow$ Tissue.

Domain

The highest taxonomic classification rank of cellular life, superseding the kingdom rank in modern biological taxonomy.

Kingdom

Historically recognized as the highest taxonomic rank in the classification of plants and animals prior to the establishment of domains.

Alexander von Humboldt

The naturalist and environmental scientist who predicted over 200 years ago that human-induced climate change would occur.

Dihydrogen Monoxide

The systematic chemical name for water ($\text{H}_2\text{O}$), a compound consisting of two hydrogen atoms covalently bound to one oxygen atom.

Inorganic Chemistry

The branch of chemistry devoted to studying the features, structures, and properties of minerals and non-carbon metallic compounds.

Species

The fundamental taxonomic unit of biodiversity that separates distinct organisms such as domestic dogs, wolves, and Chihuahuas despite genetic similarities.

Canis lupus

The scientific species classification that encompasses the forest wolf and ancestral domestic dogs.

Momentum

A physical vector quantity defined as the product of mass and velocity ($p = mv$); it doubles whenever an object's speed doubles.

Kinetic Energy

The energy of an object due to its motion, defined by $KE = \frac{1}{2}mv^2$, which quadruples if speed is doubled.

Diffusion of Water

The passive movement of water molecules across a semipermeable cell membrane driven by a concentration gradient.

Oxygen (Human Body Abundance)

The most abundant chemical element in the human body by mass, making up approximately $65\%$ of total human body weight.

Robert Hooke

The scientist who discovered and coined the term 'cell' after examining thin cork slices under a microscope in 1665.

Constant Velocity Elevator Dynamics

A mechanical state where upward cable tension equals gravity, kinetic energy remains constant, and net acceleration is zero.

Virus

A non-cellular infectious agent consisting of nucleic acid inside a protein coat that does not fit into the living kingdoms of bacteria, fungi, or worms.

Robert Whittaker

The American ecologist who established the influential five-kingdom classification system (Monera, Protista, Fungi, Plantae, Animalia) in 1969.

Five-Kingdom Classification System

The biological classification model categorizing living organisms into Monera, Protista, Fungi, Plantae, and Animalia.

Neutralization Reaction

The chemical process wherein an acid and a base react quantitatively together to yield a salt and water.

Analysis of Variance (ANOVA)

A statistical hypothesis test utilized to evaluate and compare the mean differences across three or more independent sample groups.

Two-Sample T-Test

A parametric statistical method used to evaluate whether significant statistical differences exist between the means of two individual groups.

Matter

Any physical substance that has mass and occupies space by possessing volume.

Edward Jenner

The English physician who developed the world's first successful vaccine, the smallpox vaccine, using cowpox fluid.

Louis Pasteur

The French scientist recognized as the 'Father of Modern Microbiology' who introduced pasteurization and vaccines for rabies and anthrax.

Antoine Lavoisier

The French chemist known as the 'Father of Modern Chemistry' who named and identified elements including carbon, oxygen, and hydrogen.

Phenotype

The observable physical, anatomical, and physiological characteristics of an organism, such as skin pigmentation and facial morphology.

Genotype

The complete genetic composition or allele set of an organism that governs internal traits, behavior, and temperament.

Insolation

The total amount of incoming solar electromagnetic radiation delivered to and incident upon a given surface area of the Earth.

Homeostatic Receptor

A biological sensor, such as sensory structures in the skin, that detects environmental changes and signals control centers.

Homeostatic Effector

An organ, tissue, or gland that executes physiological corrections directed by control centers to maintain dynamic equilibrium.

Gland

An organ that synthesizes and secretes chemical substances (such as hormones or sweat), serving as a homeostatic effector.

Polymerization

The chemical reaction process in which monomer molecules link covalently to generate large macromolecular chains.

Macromolecule

A very large complex molecule, such as a protein, lipid, polysaccharide, or nucleic acid, formed through polymerization.

Nuclear Energy

An energy source derived from nuclear fission that produces large electrical outputs without emitting atmospheric pollution during operation.

Mountain Biome

A high-altitude ecosystem biome characterized by steep slopes and alpine conditions, exemplified by the Cordillera mountain range.

Forest Biome

A dense, tree-dominated terrestrial ecological biome characteristic of the native indigenous habitats of the Cordillera.

Complete Blood Count (CBC)

A common clinical blood test panel assessing red cells, white cells, and platelets to evaluate hematologic health.

RT-PCR

Real-time Reverse Transcription Polymerase Chain Reaction; a molecular diagnostic method that converts RNA into DNA to detect viruses like COVID-19.

Antibiotic

A pharmacological agent formulated to kill pathogenic bacteria or prevent their proliferation and spread.

Anthelmintic

A therapeutic drug formulated to destroy and expel parasitic worms (helminths) from an infected host organism.

Diuretic

A substance or pharmaceutical compound that promotes the physiological excretion of urine by the kidneys.

Eutrophication

The dense enrichment of water bodies with minerals and nutrients that prompts excessive algal blooms, depleting dissolved oxygen.

Dissolved Oxygen Depletion

The severe reduction of oxygen gas dissolved in aquatic ecosystems, directly leading to fish kills and reduced harvest yields.

Scientific Research Steps (Chronological)

Identification of the problem $\rightarrow$ Search for related literature $\rightarrow$ Formulate hypothesis $\rightarrow$ Data gathering $\rightarrow$ Analysis and interpretation of data $\rightarrow$ Conclusion and recommendation.

Homogeneous Mixture

A physical combination of substances that displays uniform composition and macroscopic appearance throughout.

Heterogeneous Mixture

A non-uniform mixture containing physically distinct and visually identifiable substances or phases.

Biochemistry

The scientific discipline examining chemical structures, reactions, and molecular processes occurring within living organisms.

Light Polarization by Polaroid Plate

The optical transformation wherein an unpolarized beam passing through a polaroid filter has half of its light intensity transmitted.

Bacterial Pneumonia

A lung infection commonly caused by bacteria that is not typically diagnosed using RNA-based RT-PCR viral tests.

Normal Spiral Galaxy

A galaxy morphology characterized by a central nuclear bulge from which curved spiral arms radiate outwards, such as Andromeda.

Andromeda Galaxy

A prominent normal spiral galaxy possessing a distinct nuclear bulge with structured outer winding spiral arms.

Biosphere

The global zone of the Earth encompassing all ecosystems, living organisms, and their direct physical interactions.

Eukaryotic Organism

An organism composed of cells possessing complex membrane-bound organelles and a true nucleus, exemplified by fungi.

Gamete

A mature reproductive haploid sex cell (sperm or ovum) capable of uniting with another in sexual fertilization.

Thermal Conduction

The direct transfer of internal thermal energy through microscopic collisions of atoms without overall bulk motion of the material.

Biodiversity Threats Ranking

The hierarchy of ecological threats arranged from most to least harmful: Climate change $-$ pollution $-$ loss of habitat $-$ alien species.

Basic Law of Electrostatics

The fundamental physical rule stating that like charges repel each other, whereas unlike electrical charges attract.

Anton van Leeuwenhoek

The Dutch microscopist who pioneered microbiology by discovering and documenting single-celled protozoa and bacteria.

Triglycerol

A lipid compound exhibiting a low melting point, complete insolubility in water, but high solubility in organic ether.

Ole Roemer

The Danish astronomer who made the first rough quantitative estimate of the speed of light in 1676 using Io's orbital eclipses.

Centrifuge

A laboratory instrument that applies centrifugal acceleration to separate fluid, liquid, or gas mixtures based on density differences.

Formic Acid ($\text{HCOOH}$)

The stinging carboxylic acid injected by ant bites into epidermal tissue, inducing acute localized burning and pain.

Sodium Bicarbonate Solution

A mild basic solution ($\text{NaHCO}_3$) applied to soothe ant bites by neutralizing acidic formic acid.

Periodic Law

The fundamental chemical principle stating that elemental physical and chemical properties recur periodically as a function of atomic number.

Atomic Number

The total number of protons found in an atomic nucleus, dictating chemical identity and periodic properties.

Descriptive Statistics

The analytical branch of statistics focusing on calculating measures such as the mean, median, mode, and standard deviation.

Friedrich Wöhler

The German chemist recognized as the 'Father of Organic Chemistry' after synthesizing organic urea from inorganic ammonium cyanate.

Alfred Werner

The Nobel laureate known as the 'Father of Inorganic Chemistry' for his foundational work on coordination complexes and metal-ligand binding.

Thermostat

An instrument designed to monitor and regulate indoor temperature by cycling heating and air conditioning units.

Concave Makeup Mirror Magnification

The optical calculation yielding $m = 1.5$ when a face is placed $20\,\text{cm}$ from a mirror with radius of curvature $R = 120\,\text{cm}$.

Cosmology

The scientific discipline that studies the overall origins, chronological evolution, and ultimate fate of the universe.

Astrophysics

The astronomical branch that applies physical laws to explain the physical behavior, radiation, and mechanics of celestial bodies.

Asexual Reproduction

The generation of offspring from a single biological parent without gametic fusion, including budding, fission, and fragmentation.

Budding

An asexual reproductive mechanism wherein an outgrowth develops on a parent organism and detaches as a new clone.

Fragmentation

An asexual process where a parent organism breaks into distinct physical segments that regenerate into complete individual organisms.

Binary Fission

An asexual reproductive division where a single unicellular organism splits directly into two identical daughter cells.

Regeneration

The biological capacity of an organism to regrow lost tissues or regenerate whole new bodies from severed fragments.

Saprophyte

An organism, such as certain fungi or decomposing bacteria, that absorbs nourishment from decaying organic plant and animal matter.

Holozoic Nutrition

A heterotrophic nutrition mode involving ingestion of solid complex organic matter followed by internal digestion and absorption.

Autotroph

An organism capable of producing its own organic compounds from simple inorganic substrates using light or chemical energy.

Science and Technology Reciprocity

The reciprocal, interdependent relationship where scientific discoveries foster new technologies, which in turn drive advanced scientific research.

Refractive Index of Diamond

The optical property giving diamond a uniquely high index of refraction ($n \approx 2.42$), producing intense light refraction and brilliance.

Species Differentiation (Panthera)

The biological distinction showing that while lions and tigers belong to the identical genus Panthera, they belong to different species.

Parallel Resistor Circuit

An electrical arrangement where current splits down each independent branch while the voltage remains equal and constant across all branches.

Wave Diffraction

The characteristic bending, spreading, and interference of a wavefront when encountering an aperture, barrier, or slit.

Theory of Plate Tectonics

The overarching geological framework explaining continental drift, seismic dynamics, and orogeny through the movement of lithospheric plates.

Bohr Hydrogen Radius ($n=3$)

The physical radius of the third electron orbit in a Bohr hydrogen atom, calculated as $r_3 = (3)^2 \times 0.0529\,\text{nm} = 0.477\,\text{nm}$.

Mechanical Disintegration

Physical weathering actions such as frost wedging, root penetration, and abrasion that fracture rocks without altering chemical composition.

Frost Wedging

A mechanical disintegration process driven by the repeated freezing, volumetric expansion, and thawing of water inside rock fissures.

Chemical Oxidation (Weathering)

A chemical weathering reaction involving oxygen that chemically alters mineral composition, distinct from mechanical disintegration.

Solar Insolation Budget

The global radiative balance where approximately $50\%$ of incoming solar energy reaches Earth's surface, while the remainder is absorbed or reflected by the atmosphere.

Vaccine Antigen

The active molecular component within a vaccine that stimulates an immune response, training the body to recognize specific pathogens.

Nutritional Biochemistry

The biochemical subdiscipline dedicated to studying nutrient metabolism, human health, and clinical diet therapy.

Medical Biochemistry

The application of biochemical principles to clinical pathology, health maintenance, and physiological interventions such as hemodialysis.

Canis Genus

The mammalian genus containing domestic dogs (Canis lupus familiaris) and wolves (Canis lupus), which share the same species lineage.

Human Genome Project

The collaborative international biotechnology endeavor that successfully sequenced all base pairs across the entire human genome.

PHIVOLCS

The Philippine Institute of Volcanology and Seismology; the primary governmental body monitoring earthquakes and volcanic activity in the Philippines.