Microbiology Chemical Principles

Atom

the smallest unit of matter that can enter into a chemical reaction

molecule

a combination of atoms forming a specific chemical compound

chemistry

the science of the interactions between atoms and molecules

nucleus

the part of an atom consisting of the protons and neutrons; the part of a eukaryote cell that contains the genetic material

electron

a negatively charged particle in motion around the nucleus of an atom

protons

a positively charged particle in the nucleus of an atom

neutrons

an uncharged particle in the nucleus of an atom

atomic number

the number of protons in the nucleus of an atom

atomic mass

the total number of protons nad neutrons in the nucleus of an atom

chemical element

a fundamental substance composed of atoms that have the same atomic number and behave the same way chemically

Isotope

a form of chemical element in which the number of neutrons in the nucleus is different from the other forms of that element

electron shell

a region of an atom where electrons orbit the nucleus, corresponding to an energy level

energy level

potential energy of an electron in an atom

energy configuration

the arrangement of electron in shells or energy levels in an atom

valence

the combining capacity of an atom or a molecule

compound

a substance compound of two or more different chemical elements

chemical bond

an attractive force between atoms forming a molecule

ion

a negatively or positively charged atom or group of atoms

ionic bond

a chemical bond formed when atoms gain or lose electrons in the outer energy levels

cation

a positively charged ion

anion

an ion with a negative charge

covalent bond

a chemical bond in which the electrons of one atom are shared with another atom

hydrogen bond

a bond between a hydrogen atom covalently bonded to oxygen or nitrogen and another covalently bonded oxygen or nitrogen atom

molecular mass

the sum of the atomic masses of all atoms making up a molecule

mole

an amount of a chemical equal to the atomic masses of all the atoms in a molecule of the chemical

Dalton; Atomic Mass Unit (amu)

unit of mass for atoms, ions or molecules; equal 1g/mole

chemical reaction

the process of making or breaking bond between atoms

endergonic reaction

a chemical reaction that requires energy

exergonic reaction

a chemical reaction that releases energy

synthesis reaction

a chemical reaction in which two or atoms combine to form a new, larger molecule

anabolism

all synthesis reactions in a living organism; the building of complex organic molecule from simpler ones

decomposition reaction

a chemical reaction in which bonds are broken to produce smaller parts form a larger molecule

catabolism

all decomposition reactions in a living organism; the breakdown of complex organic compounds into simpler ones

exchange reaction

a chemical reaction that has both synthesis and decomposition components

Reversible reaction

a chemical reaction in which the end products can readily rever to the orginal molecules

Inorganic Compound

a small molecule that does not contain carbon and hydrogen

Organic Compound

a molecule that contains carbon and hydrogen

polar molecule

a molecule with an unequal distribution of changes

Solvent

a dissolving medium

Dissociation

the separation of a compound into positive and negative ions in solution

Solute

a substance dissolved in another substance

Ionization

The separation (dissociation) of a molecule into ions

Acid

a substance that dissociates into one or more hydrogen ions (H+) and one or more negative ions

Base

a substance that dissociates into one or more hydrogen ions (OH2) and one or more positive ions

Salt

a substance that dissolves in water to cations and anions, neither of which is H+ or OH2

pH

the symbol for hydrogen ion (H+) concentration; a measure of the relative acidity or alkalinity of a solution

Buffer

a substance that tends to stabilize the pH of a solution

Carbon Skeleton

the basic chain or ring of carbon atoms in a molecule

functional groups

an arrangement of atoms in an organic molecule that is responsible for the most of the chemical properties of the molecule

Macromolecule

a large organic molecule

polymer

a molecule consisting of a sequence of similar molecules, or monomers

monomer

a small molecule that collectively combines to form polymers

dehydration synthesis/ Condensation synthesis

a chemical reaction in which a molecule of water is released; also called dehydration synthesis

carbohydrate

an organic compound composed of carbon, hydrogen, and oxygen, with the hydrogen and oxygen present in a 2:1 ratio; includes starches, sugars and cellulose

monosaccharide

a simple sugar consisting of 3-7 carbon atoms

disaccharide

a sugar consisting of two simple sugars, or monosaccharides

Oligosaccharide

a carbohydrate consisting of 2 to approximately 20 monosaccharides

Isomer

one or two molecules with the same chemical formula but different structures

hydrolysis

a decomposition reaction in which chemical react with the H+ and OH- of a water molecule

Polysaccharide

a carbohydrate consisting of 8 or more monosaccharides joined through dehydration synthesis

Lipid

a non-water soluble organic molecule, inlcusing triglycerides, phospholipids, and sterols

Steroids

a specific group of lipids, including cholesterol and hormones

proteins

a large molecule containing carbon, hydrogen, oxygen and nitrogen (and sulfur); some have a helical structure and others are pleated sheets

Amino Acid

an organic acid containing an amino group and a carboxyl group. In alpha-amino acids the amino and carboxyl groups are attached to the same carbon atom called alpha-carbon

stereoisomers

two molecules consisting of the same atoms, arranged in the same manner but differing in their relative positions; mirror images; also called D-ismoer and L-isomer

peptide bond

a bond joining the amino group of one amino acid to the carboxyl group of a second amino acid with the loss of a water molecule

denaturation

a change in the molecular structure of a protein, usually making it nonfunctional

nucleic acid

a macromolecule consisting of nucleotides; DNA and RNA

ribonucleic acid (RNA)

the class of nucleic acids that comprises messenger RNA, ribosomal RNA and transfer RNA

nucleotide

a compound consisting of a purine or pyrimidine base, a five-carbon sugar and a phosphate

deoxyribose

a five-carbon sugar contained in DNA nucleotides

ribose

a five-carbon sugar that is part of ribonucleotide molecules and RNA

purines

the class of nucleic acid bases that includes adenine and guanine

pyrimidines

the class of nucleic acid bases that includes uracil, thymine, and cytosine

Nucleoside

a compound consisting of a purine or pyrimidine base and a pentose sugar

double helix

refers to two adjacent, antiparallel strands of DNA sound into a spiral

messenger RNA (mRNA)

the type of RNA molecule that directs the incorporation of amino acids into proteins

ribosomal RNA (rRNA)

the type of RNA molecule that forms ribosomes

transfer RNA (tRNA)

the type of RNA molecule that brings amino acids to the ribosomal site where they are incorporated into proteins

RNA interference/ RNAi

stops gene expression at transcription by using a short interfering RNA to make double-stranded RNA

adenosine triphosphate (ATP)

an important intracellular energy source

adenosine diphosphate (ADP)

the substance formed when ATP is hydrolyzed and energy is released