Chapter 02: The Chemistry of Biology Flashcards

A set of vocabulary flashcards based on Chapter 02: The Chemistry of Biology, covering fundamental chemical principles, bonds, reactions, and biological macromolecules.

Matter

All tangible materials that occupy space and have mass.

Atom

A tiny particle that cannot be subdivided into smaller substances without losing its properties.

Protons

Positively charged subatomic particles found in the nucleus.

Neutrons

Subatomic particles with no charge, also found in the nucleus.

Electrons

Negatively charged subatomic particles that surround the nucleus.

Element

An atom with a characteristic atomic structure and predictable chemical behavior.

Isotopes

Variant forms of the same element that differ in the number of neutrons.

Radioactive isotopes

Isotopes with unstable nuclei that spontaneously release energy in the form of radiation.

Orbitals

Pathways in which electrons rotate around the nucleus, representing volumes of space where an electron is likely to be found.

Valence

The number of electrons in the outermost shell of an element, which determines reactivity and bond types.

Molecule

A chemical substance resulting from the combination of two or more atoms, such as $O_2$ or $N_2$.

Compound

A molecule composed of two or more different elements, such as $H_2O$ or $C_6H_{12}O_6$.

Covalent bonds

Chemical bonds that form between atoms that share electrons rather than donating or receiving them.

Polar molecule

A molecule formed between two atoms that have different electronegativity or ability to attract electrons.

Nonpolar molecule

Molecules formed when atoms have similar electronegativity.

Ionic bonds

Bonds formed when electrons are transferred completely from one atom to another and are not shared.

Ionization

The formation of charged particles (ions) when a molecule formed by ionic bonds dissolves in a solvent.

Cations

Positively charged ions.

Anions

Negatively charged ions.

Electrolytes

Substances such as salts, acids, and bases that release ions when dissolved in water.

Hydrogen bonds

Weak, temporary bonds formed due to attractive forces between a hydrogen covalently bonded to one molecule and an oxygen or nitrogen on another.

van der Waals forces

Weak attractions between molecules that show polarity, allowing neighboring groups to interact and remain associated.

Reactants

Molecules entering or starting a chemical reaction.

Products

Substances left after a chemical reaction has occurred.

Synthesis reaction

A reaction where reactants bond together in a manner that produces an entirely new molecule.

Decomposition reaction

A reaction where bonds on a single reactant molecule are permanently broken to release two or more product molecules.

Exchange reactions

Reactions where reactants trade portions with each other to release products that are combinations of the two; expressed as $AB + XY \rightleftharpoons AX + BY$.

Catalysts

Substances that increase the rate of a reaction without being consumed in the process; enzymes fulfill this role in cells.

Solute

A substance that is uniformly dispersed in a dissolving medium.

Solvent

A dissolving medium, such as water, which is the most common example in natural systems.

Hydrophilic

Molecules, such as salt or sugar, that attract water to their surface.

Hydrophobic

Nonpolar molecules, such as benzene, that repel water.

Amphipathic

Molecules like phospholipids that possess both hydrophilic and hydrophobic properties.

Acidic solution

A solution that occurs when a component dissolved in water releases excess hydrogen ions ($H^+$).

Basic solution

A solution that occurs when a component dissolved in water releases excess hydroxyl ions ($OH^-$).

pH scale

A logarithmic scale ranging from $0$ to $14$ used to measure the acid and base concentrations of solutions.

Neutralization reactions

Reactions in which acids react with bases to give rise to water and salts.

Inorganic chemicals

Molecules that do not contain both carbon and hydrogen, such as $NaCl$, $CaCO_3$, and $CO_2$.

Organic chemicals

Molecules with a basic framework of carbon bonded to other atoms, considered the fundamental element of life.

Functional groups

Molecular groups or accessory molecules, such as $-OH$ or $-COOH$, that bind to organic compounds and confer unique reactive properties.

Biochemistry

The scientific field that explores the compounds of life.

Macromolecules

Large compounds assembled from smaller molecular subunits, including carbohydrates, lipids, proteins, and nucleic acids.

Polymerization

The process where monomers (repeating subunits) are bound into varying lengths called polymers.

Monosaccharide

A simple sugar containing three to seven carbons, such as glucose or fructose.

Polysaccharide

A polymer consisting of five or more monosaccharides.

Glycosidic bonds

Bonds in which carbons on adjacent sugar units are bonded to the same oxygen atom like links in a chain.

Dehydration synthesis

A polymerization process where one carbon group releases an $H$ and the other releases an $OH$, forming water as a byproduct.

Cellulose

A long, fibrous polymer that gives strength and rigidity to plants and microscopic algae.

Agar

A polysaccharide derived from seaweed used in preparing solid culture media.

Peptidoglycan

A network of polysaccharides linked to peptide fragments that provides structural support to bacterial cell walls.

Lipopolysaccharide

A complex of lipid and polysaccharide in the outer membrane of gram-negative bacteria responsible for fever and shock.

Glycocalyx

A layer of polysaccharides bound to proteins on the outer surface of cells, functioning in attachment or as receptor sites.

Hydrolysis

The digestion or breakdown of polysaccharides that requires the addition of water.

Triglycerides

Storage lipids composed of a single molecule of glycerol bound to three fatty acids.

Saturated fatty acid

A fatty acid where all carbons in the chain are single-bonded to two other carbons and two hydrogens.

Unsaturated fatty acid

A fatty acid in which at least one double bond exists between carbon atoms.

Phospholipids

Lipids containing two fatty acids and a phosphate group, forming the structural basis of cell membranes.

Steroids

Ringed compounds found in cell membranes and hormones; examples include cholesterol and ergosterol.

Amino acids

The building blocks of proteins, existing in $22$ naturally occurring forms.

Peptide

A molecule composed of short chains of amino acids.

Primary ($1^{\circ}$) structure

The specific type, number, and order of amino acids in a protein chain.

Secondary ($2^{\circ}$) structure

Protein patterns such as the $\alpha$ helix and $\beta$-pleated sheet formed by interactions between functional groups.

Denature

The disruption of a protein's functional, three-dimensional form through heat, acid, alcohol, or disinfectants.

Nucleotides

The repeating subunits of DNA and RNA, each consisting of a nitrogen base, a pentose sugar, and a phosphate.

Purines

Nitrogen bases with two rings, specifically Adenine ($A$) and Guanine ($G$).

Pyrimidines

Nitrogen bases with a single ring, including Thymine ($T$), Cytosine ($C$), and Uracil ($U$).

ATP

Adenosine Triphosphate, a high-energy molecule containing adenine, ribose, and three phosphates.