Microbiology: Chapter 2 Chemical Principles Flashcards

Vocabulary flashcards covering chemical principles, atomic structure, bonds, reactions, organic and inorganic compounds, and biological macromolecules based on Chapter 2.

Atom

The smallest unit of matter that cannot be subdivided into smaller substances.

Electron

A negatively charged subatomic particle arranged in electron shells corresponding to different energy levels.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

An uncharged subatomic particle found in the nucleus of an atom.

Compound

A molecule that contains two or more kinds of atoms held together by chemical bonds.

Ion

A charged atom that has gained or lost electrons.

Cation

An atom that loses electrons and becomes a positively charged ion.

Anion

An atom that gains electrons and becomes a negatively charged ion.

Ionic bond

An attraction between ions of opposite charge formed when one atom loses electrons and another gains electrons.

Covalent bond

A chemical bond formed when two atoms share one or more pairs of electrons.

Hydrogen bond

A bond formed when a hydrogen atom covalently bonded to an oxygen or nitrogen atom is attracted to another nitrogen or oxygen atom in another molecule.

Endergonic reaction

A chemical reaction that absorbs energy.

Exergonic reaction

A chemical reaction that releases energy.

Anabolism

The synthesis of molecules in a cell.

Catabolism

Decomposition reactions in a cell.

Exchange reaction

A chemical reaction that is part synthesis and part decomposition.

Organic compound

A structurally complex compound that always contains carbon and hydrogen.

Inorganic compound

A typically small, structurally simple compound that usually lacks carbon.

Acid

A substance that dissociates into one or more $\text{H}^+$ (protons) and one or more negative ions.

Base

A substance that dissociates into one or more $\text{OH}^-$ (hydroxide) ions.

Macromolecule

A large molecule formed when small organic molecules combine into polymers.

Monomer

A small repeating molecule that joins with others to form polymers or macromolecules.

Isomer

Molecules with the same chemical formula, but different structural arrangements.

Monosaccharide

A simple sugar containing three to seven carbon atoms, such as glucose and deoxyribose.

Disaccharide

A sugar molecule formed when two monosaccharides are joined together in a dehydration synthesis.

Polysaccharide

A carbohydrate consisting of tens or hundreds of monosaccharides joined through dehydration synthesis.

Dehydration synthesis

A chemical reaction where two molecules are joined together with the elimination of a water molecule.

Hydrolysis

A chemical breakdown reaction that splits a complex molecule by adding water.

Lipid

A nonpolar organic compound insoluble in water, consisting of C, H, and O, that serves as a primary component of cell membranes.

Phospholipid

A lipid molecule containing a polar, hydrophilic head and nonpolar, hydrophobic tails, forming the structural basis of plasma membranes.

Amino acid

A protein subunit consisting of an alpha-carbon attached to an amino group ($-\text{NH}_2$), a carboxyl group ($-\text{COOH}$), and a side group.

Primary structure

The specific linear sequence of amino acids forming a polypeptide strand.

Secondary structure

The localized, repetitive folding of a polypeptide chain into helix or pleated sheet structures maintained by hydrogen bonds.

Tertiary structure

The overall three-dimensional folding pattern of a polypeptide chain into a 3D shape.

Quaternary structure

The structural relationship and aggregation of several folded polypeptide chains forming a protein.

Nucleotide

A structural unit of nucleic acids consisting of a nitrogen-containing base, a pentose sugar, and a phosphate group.

Deoxyribonucleic acid (DNA)

A double-stranded, double-helical molecule containing deoxyribose that stores genetic information in cells.

Adenosine triphosphate (ATP)

A molecule composed of ribose, adenine, and three phosphate groups that stores and liberates chemical energy for cellular processes.