Chapter 1-5: Key Vocabulary from the Video Lecture on Chemistry and the Living Body

Vocabulary flashcards covering bonding, water properties, pH, emulsions, and the major biomolecules described in the lecture notes.

Element

A basic chemical substance that cannot be broken down into simpler substances by ordinary chemical means; the fundamental building block of matter.

Atom

The smallest unit of an element that retains the element’s properties; composed of a nucleus (protons and neutrons) and electrons.

Covalent bond

A chemical bond formed when two atoms share electrons.

Ionic bond

A bond formed by the transfer of electrons from one atom to another, creating oppositely charged ions that attract.

Hydrogen bond

A weak attraction between a hydrogen atom covalently bonded to an electronegative atom (like oxygen) and another electronegative atom.

Water (H2O)

A polar molecule that forms hydrogen bonds, acts as a solvent, aids transport, cushions tissues, and helps regulate temperature.

Inorganic compound

A compound that is not primarily built from carbon-hydrogen bonds; often derived from nonliving sources but can be essential to life.

Organic compound

A molecule that contains carbon (and often hydrogen and oxygen) and is typically associated with living systems.

Solvent

The dissolving medium in a solution; water is a common and highly effective solvent in biology.

Solute

The substance dissolved in a solvent within a solution.

pH

A measure of how acidic or basic a solution is, on a 0–14 scale; 7 is neutral; below 7 is acidic; above 7 is basic; scale is logarithmic.

Neutral (pH 7)

A solution with equal hydronium and hydroxide ion concentrations; neither acidic nor basic.

Acid

A substance that increases the concentration of hydrogen ions in solution, lowering pH.

Base

A substance that increases pH by reducing hydrogen ion concentration or increasing hydroxide ions.

Buffer

A system that resists changes in pH by neutralizing added acids or bases, helping maintain homeostasis.

Emulsion

A mixture of two immiscible liquids that are forced to mix, such as oil in water (as in mayonnaise).

Emulsification

The process of mixing immiscible liquids to form an emulsion, often requiring energy or emulsifying agents.

Suspension

A mixture in which larger particles are dispersed in a fluid but will settle out over time.

Centrifugation

A technique that uses high-speed spinning to separate components of a mixture by density.

Macromolecule

A very large molecule formed when smaller units bond together; includes carbohydrates, proteins, lipids, and nucleic acids.

Biomolecule

A macromolecule essential to life; a group of large, complex molecules such as carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates

Biomolecules built from sugars; provide quick energy; include monosaccharides, disaccharides, and polysaccharides (starches).

Proteins

Biomolecules made of amino acids; perform structural, enzymatic, and regulatory roles; build tissues like nails, hair, and skin.

Lipids

A group of hydrophobic biomolecules including fats, oils, and waxes; mainly carbon, hydrogen, and oxygen; often store energy and form membranes; some contain nitrogen or phosphorus.

Nucleic acids

Biomolecules (DNA and RNA) that store and transmit genetic information; built from nucleotides.

Blood

The body’s transport fluid; mostly water; carries nutrients, wastes, and cells; components can be separated by centrifugation to reveal dense components like cells.

Cerebrospinal fluid

Fluid surrounding the brain and spinal cord that cushions the nervous system.

Hydrophilic

Substances that mix well with water; water-loving and water-soluble.

Hydrophobic

Substances that do not mix with water; water-fearing, often fat-soluble.

Stomach acid (Hydrochloric acid, HCl)

A strong acid produced in the stomach to aid digestion; the stomach has protective tissues to prevent self-digestion.

Buffers and pH homeostasis

Biological systems (buffers) maintain blood and body fluid pH within a narrow range to preserve function and stability.

Emulsions vs. solutions in biology

Emulsions are mixtures of immiscible liquids (e.g., fat and water) forced to mix; solutions are homogeneous mixtures where substances are dissolved.