BIO102H Exam 1

emergent properties

New properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases

systems biology

An approack to studying biology that aims to model the dynamic behavior of whole biological systems based on a study of the interactions among the system’s parts

eukaryotic cell

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

prokaryotic cell

A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with prokaryotic cells (bacteria and archaea) are called prokaryotes

gene

A discrete unit of hereditary information of a specific nucletide sequence in DNA (or RNA, in some viruses)

genome

The genetic material of an organism or virus; the complete complement of an organism’s or virus’s genes along with its noncoding nucelic acid sequences

genomics

The study of whole sets of genes and their interactions within a species, as well as genome comparisons between species

proteomics

The systematic study of the full protein sets (proteomes) encoded by genomes

proteome

The entire set of proteins expressed by a given cell, tissue, or organism

bioinformatics

The use of computers, software, and mathematical models to process and integrate biological information from large data sets

climate change

A directional change in temperature, precipitation, or other aspect of the global climate that lasts for 3 decades or more

matter

Anything that takes up 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

essential element

A chemical element required for an organism to survive, grow, and reproduce

trace element

An element indispensable for life but required in extremely minute amounts

atom

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

neutron

A subatomic particle having no electrical charge (electrically neutral), with a mass of about 1.7x10^-24 g, found in the nucleus of an atom

proton

A subatomic particle with a single positive electrical charge, with a mass of about 1.7x10^-24 g, found in the nucleus of an atom

electron

A subatomic particle with a single negative electrical charge and a mass about 1/2000 that of a neutron or proton. One or more electrons move around the nucleus of an atom

atomic nucleus

An atom’s dense central core, containing protons and neutrons

dalton

A measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or amu

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

radioactive isotope

An isotope (an atomic form of a chemical element) that is unstable; the nucleus decays spontaneously, giving off detectable particle and energy

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)

electron shell

An energy level of electrons at a characteristic average distance from the nucleus of an atom

valence electron

An electron in the outermost electron shell

valence shell

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

chemical bond

An attraction between 2 atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells

covalent bond

A type of strong chemical bond in which 2 atoms share one or more pairs of valence electrons

molecule

2 or more atoms held together by covalent bonds

single bond

A single covalent bond; the sharing of a pair of valence electrons by 2 atoms

double bond

A double covalent bond; the sharing of two pairs of valence electrons by 2 atoms

valence

The bonding capacity of a given atom; the number of covalent bonds an atom can form, which usually equals the number of unpaired electrons in its outermost (valence) shell

electronegativity

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

nonpolar covalent bond

A type of covalent bind in which electrons are shared equally between 2 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

ion

An atom or 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

ionic compound/salt

A compound resulting from the formation of an ionic bond

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

Van de Waals interactions

Weak attractions between molecules or parts off molecules that result from transient local partial charges

chemical reactions

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

reactant

A starting material in a chemical reaction

product

A material resulting from a chemical reaction

chemical equilibrium

In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time

polar molecule

A molecule (such as water) with an uneven distribution of charges in different regions of the molecule

cohesion

The linking together of like molecules, often by hydrogen bonds

adhesion

The clinging of one substance to another, such as water to plant cell walls, in this case by means of hydrogen bonds

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid

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

temperature

A measure in degrees of the average kinetic energy (thermal energy) of the atoms and molecules in a body of matter

heat

Thermal energy in transfer from one body of matter to another

calorie

(cal) The amount of heat energy required to raise the temperature of 1 g of water by 1 degree C; also the amount of heat energy that 1 g of water releases when it cools by 1 degree C. The Calorie (with a capital C), usually used to indicate the energy content of food, is a kilocalorie

kilocalorie

(kcal) A thousand calories; the amount of heat energy required to rise the temperature of 1 kg of water by 1 degree C

joule

(J) A unit of energy: 1 joule equals 0.239 calories. 1 calorie equals 4.184 joules

specific heat

The amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1 degree C

heat of vaporization

The quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous phase

evaporative cooling

The process in which the surface of an object becomes cooler during evaporation, a result of the molecules with the greatest kinetic energy changing from the liquid to the gaseous phase

solution

A liquid that is a homogeneous mixture of 2 or more substances

solvent

The dissolving agent of a solution. Water is the most versatile solvent known

solute

A substance that is dissolved in a solution

aqueous solution

A solution in which water is the solvent

hydration sphere

The sphere of water molecules around a dissolved ion

hydrophilic

Having an affinity for water

hydrophobic

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

molecular mass

The sun of the masses of all the atoms in a molecule; sometimes called the molecular weight

mole

(mol) The number of grams of a substance that equals its molecular weight in daltons and contains Avogadro’s number of molecules

molarity

A common measure of solute concentration, referring to the number of moles of solute per liter of solution

hydrogen atom

A single proton with a charge of 1-plus. The dissociation of a water molecule leads to he generation of a hydroxide ion (O charge of 1-minus) and a hydrogen ion

hydroxide ion

A water molecule that has lost a proton; written as OH superscript minus

hydronium ion

A water molecule that has an extra proton bound to it; written as H subscript 3 O subscript plus, and commonly represented as H superscript +

acid

A substance that increases the hydrogen ion concentration of a solution

base

A substance that reduces the hydrogen ion concentration of a solution

pH

A measure of hydrogen ion concentration equal to the negative log of the concentration of hydrogen ions and ranging in value from 0 to 14

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

ocean acidification

The process by which the pH of the ocean is lowered (made more acidic) when excess carbon dioxide dissolves in seawater and forms carbonic acid

catalyst

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

polypeptide

A polymer of many amino acids linked together by peptide bonds

protein

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

amino acid

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

peptide bond

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

sickle-cell disease

A recessively inherited human blood disease in which a single nucleotide change in the beta-globin gene causes hemoglobin to aggregate, changing red blood cell shape and causing multiple symptoms in affected individuals

denaturation

In proteins, a process in which a protein loses its native shape due to the disruption of weak chemical bonds and interactions, thereby becoming biologically inactive; in DNA, the separation of the two strands of the double helix. Denaturation occurs under extreme (noncellular) conditions of pH, salt concentration, or temperature

x-ray crystallography

A technique used to study the three-dimensional structure of molecules. It depends on the diffraction of an x-ray beam by the individual atoms of a crystallized molecule

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)

catabolic pathway

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

anabolic pathway

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

bioenergetics

The overall flow and transformation of energy in an organism; the study of how energy flows through organisms

energy

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

heat

Thermal energy in transfer from one body of matter to another

potential energy

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