Chapter 02 Chemical Basis of Life

Vocabulary flashcards covering the chemical basis of life, including elements, subatomic particles, atomic structure, chemical bonding, chemical reactions, electrolytes, pH scale, and organic macromolecules from Chapter 02 of Hole's Human Anatomy & Physiology.

Matter

Anything that takes up space and has mass; composed of elements.

Mass

The amount of matter present.

Chemistry

The branch of science that studies the composition, properties, and interactions of matter.

Biochemistry

The study of physiological processes and disease at the chemical level.

Elements

The simplest types of matter, consisting of $92$ naturally occurring types.

Compounds

Chemical combinations of different elements.

Atoms

The smallest particles of an element that retain the chemical properties of that element.

Bulk elements

Elements required by the body in large amounts.

Trace elements

Elements required by the body in small amounts.

Proton ($p^+$)

A relatively large particle within an atom that carries a single positive electrical charge and is located in the atomic nucleus.

Neutron ($n^0$)

A relatively large particle within an atom that has about the same weight as a proton, carries no electrical charge, and is found in the atomic nucleus.

Electron ($e^-$)

An extremely small particle within an atom that has almost no weight, carries a single negative electrical charge, and is in constant motion around the nucleus.

Ion

A particle formed from an atom that is electrically charged because it has gained or lost one or more electrons.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Molecule

A particle formed by the chemical union of two or more atoms.

Atomic Number

The number of protons in the nucleus of an atom of a specific element.

Mass Number

The total number of protons plus neutrons in a single atom.

Isotopes

Atoms of the same element that have identical atomic numbers but different mass numbers due to differing numbers of neutrons.

Atomic weight

The average of the mass numbers of all the isotopes of an element.

Ionic Bonds

Strong chemical bonds formed by the attraction between ions of opposite electrical charge.

Covalent Bonds

Strong chemical bonds formed between atoms that share electrons.

Nonpolar covalent bonds

Covalent bonds in which electrons are shared equally between atoms.

Polar covalent bonds

Covalent bonds in which electrons are shared unequally, resulting in a molecule with unequal charge distribution.

Hydrogen bonds

Relatively weak attractions between a slightly positive hydrogen ($H$) end of one polar molecule and a slightly negative oxygen ($O$) or nitrogen ($N$) end of a nearby polar molecule.

Reactants

The starting materials in a chemical reaction, such as atoms, ions, or molecules.

Products

The substances formed at the end of a chemical reaction.

Synthesis Reaction

A chemical reaction in which two or more atoms or molecules combine to form a more complex chemical structure.

Decomposition Reaction

A chemical reaction in which chemical bonds are broken to form simpler chemical structures.

Exchange Reaction

A chemical reaction in which chemical bonds are broken and new bonds are formed to trade components.

Reversible Reaction

A chemical reaction in which the products can change back to the original reactants.

Electrolytes

Substances that release ions in water, forming a solution that can conduct an electric current.

Acids

Electrolytes that dissociate in water to release hydrogen ions ($H^+$).

Bases

Substances that release ions that can combine with hydrogen ions ($H^+$).

Salts

Electrolytes formed by the chemical reaction between an acid and a base.

pH Scale

A scale ranging from $0$ to $14$ that indicates the concentration of hydrogen ions in a solution.

Buffers

Chemicals that resist pH changes by binding and releasing hydrogen ions to regulate pH.

Organic molecules

Molecules that contain carbon ($C$) and hydrogen ($H$), are non-electrolytes, and do not release ions in water.

Inorganic molecules

Molecules that generally lack carbon ($C$) and hydrogen ($H$), usually dissolve in water, dissociate into ions, and act as electrolytes.

Carbohydrates

Water-soluble organic compounds containing carbon ($C$), hydrogen ($H$), and oxygen ($O$) with an $H$ to $O$ ratio close to $2:1$, serving as the main source of cellular energy.

Monosaccharides

Single sugars, such as glucose and fructose, that serve as the fundamental units of carbohydrates.

Disaccharides

Double sugars formed by combining two monosaccharides, such as sucrose and lactose.

Polysaccharides

Complex carbohydrates made of many linked simple sugars, such as starch, glycogen, and cellulose.

Lipids

Organic molecules insoluble in water that include triglycerides, phospholipids, and steroids.

Triglycerides

The most abundant lipids in the body, composed of $1$ molecule of glycerol and $3$ fatty acid chains, used for cellular energy or storage.

Saturated fatty acids

Fatty acids containing only single carbon-carbon bonds, typically solid at room temperature and primarily of animal origin.

Unsaturated fatty acids

Fatty acids containing one or more carbon-carbon double bonds, typically liquid at room temperature and primarily of plant origin.

Phospholipids

Lipid molecules consisting of glycerol, $2$ fatty acid chains, and a phosphate group, forming the main structural component of cell membranes.

Steroids

Lipids composed of $4$ connected rings of carbon, used as membrane components and precursors for synthesizing adrenal and sex hormones.

Proteins

Organic macromolecules made of amino acids that function as structural materials, energy sources, hormones, receptors, enzymes, and antibodies.

Amino acids

The building blocks of proteins, containing an amino group ($-\text{NH}_2$), a carboxyl group ($-\text{COOH}$), and a unique $R$ (side chain) group.

Peptide bonds

Covalent bonds formed between the amino group of one amino acid and the carboxyl group of an adjacent amino acid.

Primary structure

The specific sequence of amino acids in a polypeptide chain.

Secondary structure

The pleated or twisted structure of a polypeptide chain formed by hydrogen bonding between nonadjacent amino acids.

Tertiary structure

The unique three-dimensional folded shape, or conformation, of a protein molecule that determines its specific biological function.

Quaternary structure

The structure formed when two or more distinct polypeptide chains combine to form a single protein molecule.

Denaturation

A change in the secondary and tertiary structure of a protein caused by heat, radiation, pH changes, or chemicals, which stops enzymes and other functional proteins from working.

Nucleic acids

Organic macromolecules that carry the genetic code (DNA) or assist in protein synthesis (RNA), composed of chains of nucleotides.

Nucleotides

The building block units of nucleic acids, each consisting of a 5-carbon sugar ($S$), a phosphate group ($P$), and an organic base ($B$).

DNA (Deoxyribonucleic acid)

A double-stranded, helical nucleic acid containing the sugar deoxyribose that stores the genetic code.

RNA (Ribonucleic acid)

A single-stranded nucleic acid containing the sugar ribose that interacts with DNA to conduct protein synthesis.