Domain Archaea
Prokaryotic, single-celled organisms; have cell walls; reproduce using binary fission (duplication); RNA sequence is most similar to Eukarya; live in extreme environments and therefore do not infect humans; oldest life forms; include methanogens, extreme thermophiles, and extreme halophiles
Domain Bacteria
Prokaryotic, single-celled organisms; have cell walls; reproduce using binary fission; differ from archaea in environment and materials in cell wall; includes cyanobacteria
Biology
The scientific study of life and its processes
Biosphere
"Largest ecosystem"; the Earth from atmosphere to core
Cell
An organism's basic unit of structure and function; enclosed by a membrane that regulates the passage of materials between its insides and its surroundings; uses DNA as genetic information
Community
A set of populations in a given area
Consumer
A heterotroph; an organism that obtains organic food molecules by eating other organisms or substances derived from them
Controlled Experiment
An experiment in which an experimental group is compared with a control group that varies only in the factor being tested
Domain Eukarya
All organisms made up of eukaryotic cells; includes the Kingdoms Plantae, Animalia, Fungi, and protists
Emergent Properties
Properties that become apparent as complexity is elevated
Eukaryotic Cell
Has a "true nucleus," and organelles with membranes; is much larger than the other type of cell
Gene
A unit of inheritance; determines physical traits
Genome
The entire genetic library of an organism
Theory
A widely accepted explanation of a biological phenomenon based on sound evidence from rigorous empirical experiments and scientific observations
Hypothesis
A testable explanation for a set of observations based on the available data and guided by inductive reasoning; narrower in scope than a theory
Inductive Reasoning
Bottom-up approach; a type of logic in which generalizations are based off a number of specific observations; specific to general
Deductive Reasoning
Top-down approach; specific results are predicted from a general premise; general to specific
Kingdom Animalia
A Kingdom of Domain Eukarya; multicellular, includes heterotrophic organisms with no cell wall
Kingdom Fungi
A Kingdom of Domain Eukarya; members have cell walls made of chitin, decompose organic material to obtain nutrients, and digest food outside themselves using enzymes
Kingdom Plantae
A Kingdom of Domain Eukarya; members are photosynthetic, have cell walls made of cellulose, and are multicellular
Positive Feedback
Regulation in which the end product speeds up its own production
Negative Feedback
Regulation in which accumulation of an end product of a process slows that process
Organ/Organ System
Functions as organelles do in cells, serving various purposes in an organism's body
Organelles
Small, usually membranous; located in the cytoplasm of eukaryotic cells
Organisms
Individual living things
Population
All individuals of a species within a given area
Producer
An autotroph; an organism that obtains organic food molecules using energy from the sun or oxidation of inorganic substances
Prokaryotic Cell
A type of cell lacking organelles and a "true nucleus;" found in unicellular organisms
Reductionism
An approach of reducing complex systems into simpler compounds that are more manageable to study; has limitations due to emergent properties
Systems Biology
An approach that attempts to model the dynamic behavior of whole biological systems based on a study of the interactions among the system's parts
Cyanobacteria
Members of Domain Bacteria; photosynthetic; produce oxygen and contain chlorophyll
Atom
The smallest unit of matter that still retains the properties of an element
Atomic Mass
An approximation of the total mass of an atom; measured in daltons
Atomic Nucleus
A dense core at the center of an atom containing protons and neutrons
Atomic Number
The number of protons in an element; written as a subscript
Cation
A positively charged ion
Anion
A negatively charged ion
Chemical Bond
An attraction that holds atoms together
Compound
A substance consisting of two or more different elements combined in a fixed ratio
Covalent Bond
The sharing of a pair of valence electrons by two atoms
Electron
A negatively charged subatomic particle
Electron Shells
Levels of differing energy in the electron cloud
Electronegativity
The attraction of a particular atom for the electrons of a covalent bond; the thirstiness of an atom
Element
A substance that cannot be broken down to other substances by chemical reactions
Energy
The capacity to cause change
Energy Level
Another name for an electron shell
Hydrogen Bond
The non-covalent attraction between a hydrogen atom and an electronegative atom; weak chemical bond
Ion
A charged atom
Ionic Bond
Chemical bond that occurs as a result of the transfer of an electron between two elements; usually present between a metal and a nonmetal
Ionic Compounds
Compounds formed by Ionic Bonds; also known as salts
Isotope
Different atomic forms of the same element; has more or less neutrons than usual
Mass Number
The sum of neutrons and protons in an atom; written as a superscript
Matter
Anything that has mass and takes up space
Molecular Formula
A formula giving the number of atoms of each of the elements present in one molecule of a specific compound
Molecule
Two or more atoms held together by covalent bonds
Neutron
A neutral subatomic particle
Nonpolar Covalent Bond
A covalent bond between two elements of the same electronegativity
Orbital
The three-dimensional space where an electron is found 90% of the time
Periodic Table of the Elements
A tabular display of the chemical elements
Polar Covalent Bond
A type of covalent bond that occurs when one atom is more electronegative than the other
Potential Energy
The energy that matter possesses because of its location or structure
Proton
Positively charged subatomic particle
Radioactive Isotope
An isotope in which the nucleus decays spontaneously, giving off particles and energy
Structural Formula
A formula that shows the arrangement of atoms in the molecule of a compound
Valence
Number of open electron spots on an atom's valence shell
Valence Electrons
Electrons on an atom's valence shell
Valence Shell
The outermost electron shell of an atom
Van der Waals Interactions
A weak attractive force between atoms or non-polar molecules caused by a temporary change in dipole moment arising from a brief shift of orbital electrons to one side of one atom or molecule, creating a similar shift in adjacent atoms or molecules
Polar Molecule
A molecule consisting of polar covalent bonds; overall charge is unevenly distributed
Cohesion
The tendency of water to be attracted to itself; occurs due to multiple hydrogen bonds
Adhesion
The clinging of one substance to another
Surface Tension
The measure of how difficult it is to break or stretch a liquid
Specific Heat
The amount of heat that must be absorbed or lost for 1 gram of a substance to change its temperature by 1 degree Celsius
Heat of Vaporization
The quantity of heat that a liquid must absorb for 1 gram of it to be converted from the liquid to the gaseous state
Evaporative Cooling
As a liquid evaporates, the surface of the liquid that remains behind cools down - this is known as ____________
Solution
A liquid that is a completely homogenous mixture of two or more substances
Solvent
The dissolving agent of a solution
Solute
The substance in a solution being dissolved
Hydration Shell
The sphere of water molecules around each dissolved ion in a solution
Hydrophyllic
Describes any substance that has an affinity for water
Hydrophobic
Describes any substance that is repelled by water
Hydrogen Ion
A single proton with a charge of 1+
Hydroxide Ion
A water molecule that has lost a proton; has a charge of 1-
Acid
Substance that increases the hydrogen ion concentration of a solution
Base
Substance that decreases the hydrogen ion concentration of a solution
pH
The negative logarithm of the hydrogen ion concentration
Buffer
A substance that minimizes changes in the concentration of H+ and OH- in a solution
Organic Chemistry
Branch of chemistry that specializes in the study of carbon compounds
Hydrocarbons
Organic molecules consisting of only Carbon and Hydrogen atoms
Isomers
Compounds that have the same molecular formula but different structures/properties
Structural Isomers
Isomers that differ in the covalent arrangements of their atoms
Geometric Isomers
Also known as cis-trans isomers; have covalent bonds to the same atoms, but differ in their spatial arrangements due to the inflexibility of double bonds
Enantiomers
Isomers that are mirror images of each other
Functional Groups
Groups of compounds that are important in biological chemical reactions
Hydroxyl Group
In a ____________, a hydrogen atom is bonded to an oxygen atom, which in turn is bonded to the carbon skeleton of the organic molecule; Alcohols; polar (--OH)
Carbonyl Group
A ____________ consists of a carbon atom joined to an oxygen atom by a double bond; Ketones and Aldehydes (which can be structural isomers); found in sugars; polar (>CO)
Carboxyl Group
When an oxygen atom is double bonded to a carbon atom that is also bonded to an --OH group, the entire assembly is called a ____________; Carboxylic Acids or organic acids; acidic; polar (--COOH)
Amino Group
The ____________ consists of a nitrogen atom bonded to two hydrogen atoms and to the carbon skeleton; Amines; basic; polar (--NH2)
Sulfhydryl Group
A ____________ consists of a sulfur atom bonded to an atom of hydrogen; it resembles of hydroxyl group in shape; Thiols; polar (--SH)
Phosphate Group
In the ____________, a phosphorus atom is bonded to four oxygen atoms; one oxygen is bonded to a carbon skeleton; two oxygens carry negative charges; Organic phosphates; polar (--OPO3^2-)