General Biology Vocabulary Flashcards

Vocabulary flashcards directly generated from biology lecture transcript definitions.

Hypothesis

A testable explanation for a set of observations based on the available data and guided by inductive reasoning. A hypothesis is narrower in scope than a theory.

Independent variable

A factor whose value is manipulated or changed during an experiment to reveal possible effects on another factor (the dependent variable).

Dependent variable

A factor whose value is measured during an experiment or other test to see whether it is influenced by changes in another factor (the independent variable).

Eukaryote

A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with eukaryotic cells (protists, plants, fungi, and animals) are called eukaryotes.

Prokaryote

Organism composed of a cell lacking nucleus and membrane enclosed organelle

Binomial nomenclature

Term for 2 part format for naming species.

Natural selection

Process in which individuals with inherited traits tend to survive and reproduce at height rates.

Matter

Anything that occupies space and has mass.

Element

Any substance that cannot be broken down to any other substance by chemical reactions.

Compound

A substance consisting of two or more different elements combined in a fixed ratio.

Atom

The smallest unit of matter that retains the properties of an element.

Neutrons

A subatomic particle having no electrical charge (electrically neutral), with a mass of about $1.7 \times 10^{-24}\,g$, found in the nucleus of an atom

Protons

A subatomic particle with a single positive electrical charge with a mass of about $1.7 \times 10^{-24}\,g$, found in the nucleus of an atom.

Electrons

A subatomic particle with a single negative electrical charge and a mass about 1 two-thousandths that of a neutron or proton. One or more electrons move around the nucleus of an atom.

Atomic number

The number of protons in the nucleus of an atom, unique for each element and designated by a subscript.

Mass number

The total number of protons and neutrons in an atom's nucleus.

Atomic mass

The total mass of an atom, numerically equivalent to the mass in grams of 1 mole of the atom. For an element with more than one isotope, the atomic mass is the average mass of the naturally occurring isotopes, weighted by their abundance.

Isotopes

One of several atomic forms of an element, each with the same number of protons, but a different number of neutrons, thus differing in atomic mass.

Valence shell

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.

Covalent bond

A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.

Single bond

A single covalent bond; the sharing of a pair of valence electrons by two atoms.

Double bond

A double covalent bond; the sharing of two pairs of valence electrons by two atoms.

Triple bond

A chemical link where 2 atoms share 6 electrons. (3 pairs)

Nonpolar covalent bond

A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.

Polar covalent bond

A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

Electronegativity

The attraction of a given atom for the electrons of a covalent bond.

Ions

An atom or a group of atoms that has gained or lost one or more electrons, thus acquiring a charge.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Ionic bond

A chemical bond resulting from the attraction between oppositely charged ions.

Hydrogen bond

A type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule.

Chemical reactions

The making and breaking of chemical bonds, leading to changes in the composition of matter.

Reactants

A starting material in a chemical reaction.

Products

A material resulting from a chemical reaction.

Hydrophobic

Having no affinity for water; tending to coalesce and form droplets in water.

Hydrophilic

Having no affinity for water; tending to coalesce and form droplets in water.

Surface tension

Having no affinity for water; tending to coalesce and form droplets in water.

Cohesion

Having no affinity for water; tending to coalesce and form droplets in water.

Adhesion

Having no affinity for water; tending to coalesce and form droplets in water.

Specific heat

Having no affinity for water; tending to coalesce and form droplets in water.

Evaporative cooling

Having no affinity for water; tending to coalesce and form droplets in water.

Solution

Having no affinity for water; tending to coalesce and form droplets in water.

Solvent

Having no affinity for water; tending to coalesce and form droplets in water.

Solute

Having no affinity for water; tending to coalesce and form droplets in water.

Aqueous solution

Having no affinity for water; tending to coalesce and form droplets in water.

Acid

A substance that increases the hydrogen ion concentration of a solution.

Base

A substance that reduces the hydrogen ion concentration of a solution.

Buffer

A solution that contains a weak acid and its corresponding base. A buffer minimizes changes in pH when acids or bases are added to the solution.

Organic chemistry

A substance that reduces the hydrogen ion concentration of a solution.

Hydrocarbon

An organic molecule consisting only of carbon and hydrogen.

Functional groups

A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions.

Isomers

One of two or more compounds that have the same numbers of atoms of the same elements but different structures and hence different properties.

Adenosine Triphosphate

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

Carbohydrates

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

Proteins

A biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure.

Lipids

Any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.

Nucleic acids

A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types are DNA and RNA.

Monomer

The subunit that serves as the building block of a polymer.

Polymer

A long molecule consisting of many similar or identical monomers linked together by covalent bonds.

Dehydration reaction

A chemical reaction in which two molecules become covalently bonded to each other with the removal of a water molecule.

Hydrolysis

A chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers to monomers.

Monosaccharides

The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also called simple sugars, monosaccharides have molecular formulas that are generally some multiple of $CH_2O$.

Polysaccharides

A polymer of many monosaccharides, formed by dehydration reactions.

Disaccharide

A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed by a dehydration reaction

Glycosidic linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

Starch

A storage polysaccharide in plants, consisting entirely of glucose monomers joined by glycosidic linkages.

Glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

Cellulose

A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by beta glycosidic linkages.

Chitin

A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods.

Fats (triglycerides)

A lipid consisting of three fatty acids linked to one glycerol molecule; also called a triacylglycerol or triglyceride.

Phospholipids

A lipid made up of glycerol joined to two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids act as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head. Phospholipids form bilayers that function as biological membranes.

Steroids

A type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached.

Saturated fatty acid

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that are attached to the carbon skeleton.

Unsaturated fatty acid

A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

Amino acids

An organic molecule possessing both a carboxyl and an amino group. Amino acids serve as the monomers of polypeptides.

Polypeptide

A polymer of many amino acids linked together by peptide bonds.

Peptide bond

The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction.

Nucleotides

The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and one to three phosphate groups.

Polynucleotides

A polymer consisting of many nucleotide monomers in a chain. The nucleotides can be those of DNA or RNA.

Pyrimidines

One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring. Cytosine (C), thymine (T), and uracil (U) are pyrimidines.

Purines

One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring fused to a five-membered ring. Adenine (A) and guanine (G) are purines.

ATP

(adenosine triphosphate) An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

Metabolism

The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.

Metabolic pathway

A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathway).

Anabolic pathway

A metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules.

Catabolic pathway

A metabolic pathway that releases energy by breaking down complex molecules to simpler molecules.

Energy

The capacity to cause change, especially to do work (to move matter against an opposing force).

Potential energy

The energy that matter possesses as a result of its location or spatial arrangement (structure).

Kinetic energy

The energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter.

Thermal energy

Kinetic energy due to the random motion of atoms and molecules; energy in its most random form; Thermal energy in transfer from one body of matter to another.

Chemical energy

Energy available in molecules for release in a chemical reaction; a form of potential energy.

Thermodynamics

The study of energy transformations that occur in a collection of matter; The principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed and the principle stating that every energy transfer or transformation increases the entropy of the universe. Usable forms of energy are at least partly converted to heat.

Entropy

A measure of molecular disorder, or randomness.

Free energy

The portion of a biological system’s energy that can perform work when temperature and pressure are uniform throughout the system. The change in free energy of a system ($\Delta G$) is calculated by taking the change in enthalphy ($\Delta H$) and subtracting the product of the temperature ($T$) and the change in entropy ($\Delta S$). In biological systems, the change in enthalphy is equivalent to total energy, and the change in temperature is the absolute temperature.

Endergonic reaction

A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings.

Exergonic reaction

A spontaneous chemical reaction in which there is a net release of free energy.

Catalyst

A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction.

Enzyme

A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. Most enzymes are proteins.

Activation energy

The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation.

Substrate

The reactant on which an enzyme works.