Science Terms and Definitions

Adenosine triphosphate (ATP) – A compound made up of adenine (a nitrogen-containing compound) bonded to ribose (a five-carbon sugar) and three phosphate groups

Anabolism – A process that living things undergo to synthesize new products

Binary fission – A process wherein unicellular organisms reproduce by splitting into two genetically identical cells

Binomial nomenclature – A system of naming organisms such that scientific names using the genus and the species names are assigned to each organism

Biome – A large community unit that comprises a distinctive natural ecosystem in a particular region

Biosphere – The thin layer on Earth’s surface and the only place in the Solar System where we know life can exist

Catabolism – A process wherein living things break down food into simpler forms to release the stored energy

Cell cycle – The continuous process of cell division and growth

Cellular respiration – The release of energy from the breakdown of food molecules (sugars) in the presence of oxygen

Chromatids – Referred to as sister chromatids because they are identical copies due to DNA replication in the S phase of the cell cycle

Commensalism – A type of symbiotic relationship wherein one organism benefits from the other without causing harm

Decomposers – The organisms that act on the remains and excretions of all organisms and reduce these to simplest forms so that they can be reused

Diffusion – A process wherein molecules of a substance move from an area of higher concentration to areas of lower concentration

Ecological efficiency – Refers to the percentage amount of energy transferred from one trophic level to the next

Ecosystem – A community of organisms interacting with their physical environment

Eutrophication – A condition wherein nutrients exceed the actual amount needed, resulting in an imbalance in nature

Evolutionary adaptation – Refers to the traits an organism possesses as a consequence of environmental conditions

Evolution – All the changes that have transformed living things on Earth from the simplest life-forms to the diverse organisms that exist today

Fermentation – A chemical reaction wherein carbohydrates are degraded into alcohol or acids using oxygen

Food chain – A process of eating and being eaten through which energy (abiotic factor) is passed on from one organism (biotic factor) to another

Fossils – Any preserved parts or traces of an organism that once lived

Genes – The units of hereditary information

Filtrate – The liquid that passes through the filter

Filtration – The process of separating a mixture composed of a solid and a liquid

Functional groups – Groups of atoms attached to carbon chains which are responsible for many of the characteristics of organic compounds

Gay Lussac’s Law – The law that states that the volume of gases used or produced in a chemical reaction can be expressed in ratios of small whole numbers under the same temperature and pressure

Graham’s Law of Diffusion – The law that states that the rates of diffusion of gases are inversely proportional to the square roots of their masses under constant temperature

Ground state – A stationary energy level normally occupied by electrons of relatively low energy level

Half-life – The length of time required fro a radioactive substance to decay to one-half of its original mass

Heterogeneous mixtures – Those that have two or more phases with definite boundaries

Homogeneous mixtures – Those that have the same properties throughout the system and show only one phase

Hydrogen bond – A bond formed between a hydrogen atom of one molecule and an electronegative atom of another molecule

Hygroscopic substance – A substance that readily absorbs moisture

Indicator – A substance which changes to a characteristic color in a reaction to the presence of a different substance

Ineffective collisions – Collisions that do not result in a chemical reaction

Inhibitors – Substances that interfere with the action of catalysts

Intermolecular forces of attraction – Much weaker forces that can hold molecules together and are responsible for the changes that occur in materials

Ionic bond – an electrostatic attraction between differently charged ions, cations and anions which involves a transfer of electrons from one atom to another

Ionization energy – The energy added to an atom to remove an outermost electron to form an ion

Ions – Atoms or a group of atoms carrying a charge

Isomer – A compound with the same molecular formula as another compound but with different structural formula

Isotopes – Atoms of the same element that have different atomic masses but of the same atomic number

Nature and behavior of gases – are influences by four quantities: pressure, temperature, volume and number of particles.

Pressure – is the force exerted per unit area of a surface

Temperature – is the measure of the average kinetic energy possessed by a body

Volume – is the amount of space an object occupies

Molecular Mass – is another factor that affects the rate of diffusion

Graham’s Law of Diffusion – states that the rate of diffusion of gases is inversely proportional to the square root of their masses under constant temperature

Boyle’s Law – states that at constant temperature, the volume of a gas is inversely proportional to the pressure

Avogadro’s Principle – states that at the same temperature and pressure, all gases that have the same volume have the same number of particles

Dalton’s Law of Partial Pressures – states that the total pressure of a mixture of gases is equal to the sum of the partial (individual) pressures of the component gases.

The Ideal Gas Law – is the combination of three special gas laws, namely Avogadro’s Boyle’s and Charles’ laws

Gases – are involved in such biological processes as photosynthesis and respiration.

Extrinsic property – is that which changes when the amount of material undergoes change. Examples of this property are mass, length and volume.

Intrinsic property – does not depend on the size or amount of the substance. Examples of this property are temperature, color, odor, hardness, density, melting and boiling point and molecular weight.

Homogeneous mixtures – have the same properties throughout the system and show only one phase. A solution is a homogeneous mixture. It is composed of a solute and solvent with uniform appearance.

Heterogeneous mixtures – shows two or more phases with definite boundaries. Suspensions are heterogeneous mixtures with undissolved particles in a liquid that tend to settle. Colloids are composed of particles that are suspended in the liquid. These particles scatter light.

Pure substances – cannot be broken down into simpler substances. They have a homogeneous or uniform appearance and composition. A substance may be an element or a compound.

Element – is the simplest form of matter and cannot be broken down or separated further even by chemical means.

Compound – is a chemical combination of two or more elements. It can be separated only by chemical means.

Metals – are elements that possesses metallic luster. They are good heat and electrical conductors. They are ductile and malleable object.

Organic compounds – are compounds that contain carbon while inorganic compounds are those containing no carbon.

Acids – are compounds that release hydrogen ions (H+) when dissolved in water. They have a sour taste and may be corrosive. They change blue litmus paper to red.

Bases – are compounds that release hydroxide (OH-) ions when dissolved in water. They have a characteristic bitter taste and are slippery to the touch. They turn red litmus paper to blue.

Salts – are compounds produced by neutralization

Compounds – are generally classified as organic and inorganic

Nonpolar bond – a bond where the electric charges are uniformly distributed

Nucleic acids – large molecules of biological systems which perform the essential functions of storage and transmission of genetic information the collective name for protons and neutrons

Nucleons – the collective name for protons and neutrons

Octet rule – a rule which states the tendency of most atoms to have eight electrons in their valence shell during the formation of bonds

Oxidation – the loss of electrons by a substance or the increase in its oxidation number

Peptide bond – a special case of an amide bond formed between an amino group of one acid and the carboxyl group of a second amino acid an instrument used to measure the concentration of hydrogen or hydroxide ions

pH meter – an instrument used to measure the concentration of hydrogen or hydroxide ions

Polar bond – a bond wherein the electric charges are unevenly distributed and is formed when atoms of different electronegativities bond with each other

Polymers – giant molecules consisting of repeating structural units

Precision – the degree of agreement between different measurements obtained under the same conditions

Proton – a positively charged subatomic particle

Pyrolysis – the decomposition of a compound by the action of the heat alone in the absence of O2.

Quark theory – the theory that states that leptons and quarks are the fundamental particles and not the electron, protons and neutron

Quarks – smaller charged particles comprising the protons and neutrons

Radioactivity – the spontaneous emission of high-energy radiation or high-energy particles from the nucleus of an atom

Rancidity – a property developed by fats and oil left at room temperature in which they develop an unpleasant odor and flavor

Reduction – the gain of electrons by a substance or the decrease in its oxidation number

Residue – the solid retained in the filter after filtration

Scientific notation – a system of expressing numbers as products consisting of a number between 1 and 10 multiplied by an appropriate power of 10

Combustion – a rapid oxidation reaction where heat and flame are given off

Condensation – the process by which gas changes into liquid

Covalent bond – a type of chemical bond that involves the sharing of electrons

Crystallization – the process by which the solvent is allowed to evaporate until the solution becomes supersaturated

Decantation – the process of separating heavy, coarse and insoluble solids from liquids

Decomposition reaction – a reaction which involves the breakdown of a compound into two or more substances

Denaturation – the process by which hydrogen bonds in proteins are broken, changing the structure and reactivity without breaking the peptide linkages

Deposition – the process by which gas changes into solid

Dialysis – a method of purifying colloids wherein substances are separated using semipermeable membrane

Dipole – partial positively and negatively charged ends exhibited by a polar molecule

Dipole-dipole force – the partial attraction between polar molecules

Distillation – the process of separating a mixture composed of volatile components

DNA – two complementary strands in which the based are linked side by side with hydrogen bonds and wound around each other in a double helix

Double displacement reaction– a reaction in which two compounds consisting of ions react by exchanging ions

Ductility – the property of metals to be drawn into wires

Effective collisions – collisions that result in a chemical reaction

Electron affinity – the energy released by an atom when an electron is added to it

Electron dot notation – also known as the Lewis structures. It is a way of representing valence electrons by dots placed around the chemical symbol of the element

Electronegativity – the tendency of an atom to attract a shared pair of electrons to itself

Empirical formula – an expression of the smallest whole number ratio of the numbers of atoms of each element in a substance

Emulsifier – a substance that helps disperse tiny particles of one liquid to another

Emulsion – a colloid that contains tiny droplets of liquid dispersed in another liquid

Endothermic reaction – a chemical reaction that absorbs energy in the form of light and electricity

Enthalpy – the heat content of a substance used in measuring the net of energy change involved during bond-making and bond-breaking

Evaporation – the process of separating a volatile substance from a nonvolatile one

Exothermic reaction – a chemical reaction that releases energy in the form of heat, light, electricity and other forms of energy

Parasitism – a symbiotic relationship in which one organism lives at the expense of another

Pedigree – a record of how a trait is inherited from generation to generation over several generations

Photoperiodism – the process of plants to changing light and dark periods

Photosynthesis – the process by which plants use the energy coming from the Sun to produce carbohydrates or sugars

Scientific method – the logical way used by scientists to solve their problems or to answer their questions

Serendipity – accidental discovery

Species – organisms possessing similar anatomical characteristics and which are capable of interbreeding

Spermatogenesis – starts when the cell develops into a primary spermatocyte then undergoes the first meiotic division

Transgenic organisms – organisms that have genes transplanted from other animals usually of different species; products of a technology wherein scientists insert genes into animals to increase their size and weight

Taiga – stretches from Canada to Siberia. This foggy biome is dominated by conifers which include pines, firs and spruces. These trees are able to withstand extreme cold during winter. Snow is the form of precipitation in a taiga biome.

Desert – h as an extremely hot daytime temperature, reaching as high as 60°C. In contrast, it’s freezing nighttime temperature can drops as low as 5°C. Rainfall is sparse and evaporation is rapid. Organisms here experience the most drastic temperature changes. This biome has hot days and cold nights with high winds due to the absence of water vapor in the air.

SOME SPECIFIC SCIENCE OF BIOLOGY

Anatomy – the study of the morphology (form and structure) of organism and their elements

Bacteriology – the study of bacteria

Biochemistry – the study of the molecules within the cell and the chemistry or the chemical composition of living things

Cytology – the study of the formation, structure, pathology and function of cells

Embryology – the study of the formation, early growth and development of organisms

Entomology – the study of insects

Epidemiology – the study of patterns of diseases within a certain population, determining causes of diseases and how they spread

Ethnobotany – the study of the way plants are identified, classifies and used by various cultures

Herpetology – the study of reptiles and amphibians

Histology – the study of the minute structures of plant and animal tissues

Ichthyology – the study of fishes

Mammalogy – the study of mammals

Marine ecology – the study of the development, function and environment of organisms in the ocean

Mycology – the study of fungi

Ornithology – the study of birds

Paleontology – the study of fossils

Parasitology – the study of parasitism

Pathology – the study of the nature of diseases and their causes, processes, development, functions and activities of organisms

Terrestrial ecology – the study of the structures, development and functions of organisms

Virology – the study of viruses and viral disease

Biomes - are large community units that comprise a distinctive natural ecosystem in a particular region.

Biosphere – is a collection of several biomes.

Tropical Rainforest – are characterized by year-round warm temperature.

Phylum Labyrinthomorpha – are aquatic, although some are on land. Organisms of this phylum form colonies of cells that can move only when surrounded with slime.

Phylum Apicomplexa. All of the species of this phylum are parasitic. They posses apical complexes to penetrate host cells.

Phylum Microspora – As the name implies, the species of this phylum produce small spores during life cycle.

Phylum Myxomycota – are cellular slime molds that produces spore through meiosis and develop fruiting bodies with cell walls.

Phylum Ciliophora – are ciliated a distinguishing characteristic of this group.

Phylum Sporozoa – are mostly parasitic organisms.

Class Chondrichthyes – the members of this class are fishes with skeletons made up of cartilage, instead of bones.

Class Osteichthyes – the members of this class are called bony fishes because their skeletons are made up of bones.

Johanne Jacob Berzelius – invented the present system of chemical symbol.

Periodic Table – is the systematic arrangement of elements according to their atomic number.

John Dalton – set a table of elements according to their atomic weights.

Dmitri Mendeleev – arranged the elements in increasing order of atomic mass, leaving gaps for undiscovered elements.

Periodic Law – states that the chemical and physical properties of the elements vary periodically with increasing atomic number.

Electron affinity – is the energy released by an atom when an electron is added to it.

Electron negativity – is relative tendency of an atom to attract electrons to itself.

Periodic properties of elements – repeat at regular intervals corresponding to their positions in the periodic table

Atomic size – increased within a family due to the addition of energy levels.

Ionization energy – is the energy required to remove valence electrons in an atom.