Chapter 02: Chemical Basis of Life

Comprehensive vocabulary flashcards covering the chemical basis of life, including atomic structure, chemical bonding, reactions, pH, and the major organic and inorganic constituents of cells.

Matter

Anything that takes up space and has mass; it encompasses solids, liquids, and gases.

Mass

The amount of matter present in a substance.

Weight

The heaviness of an object resulting from the gravitational pull acting on its mass.

Biochemistry

The study of biological chemistry relative to physiological processes and disease.

Elements

The simplest types of matter possessing specific chemical properties, including $92$ naturally occurring varieties.

Compounds

Chemical combinations consisting of different elements.

Atoms

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

Bulk elements

Elements required by the body in large amounts, such as carbon ($C$), oxygen ($O$), hydrogen ($H$), nitrogen ($N$), sulfur ($S$), and phosphorus ($P$).

Trace elements

Elements required by the body in small amounts, such as iron ($Fe$) and iodine ($I$).

Ultratrace elements

Elements required by the human body in very minute amounts, such as arsenic ($As$).

Protons

Relatively large subatomic particles carrying a single positive charge ($p^+$) found within the nucleus.

Neutrons

Relatively large subatomic particles with no electrical charge ($n^0$) found within the nucleus.

Electrons

Extremely small particles carrying a single negative charge ($e^-$) that are in constant motion around the nucleus.

Nucleus

The central part of an atom composed of protons and neutrons.

Atomic Number

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

Mass Number

The sum of the number of protons and neutrons in one atom.

Isotopes

Atoms that have the same atomic number but different mass numbers due to varying numbers of neutrons.

Atomic Weight

The average of the mass numbers of all isotopes for a specific element.

Iodine-131

A radioactive isotope used to destroy cancerous thyroid gland tissue or assess physiological functions.

Ionizing Radiation

Energy (alpha, beta, or gamma) capable of removing electrons from atoms to form ions, potentially damaging nearby atoms.

Molecule

A particle formed when two or more atoms chemically combine.

Molecular Formula

A depiction showing the types of elements and the number of each atom present in a molecule, such as $H_2O$ or $C_6H_{12}O_6$.

Electron Shells

Regions of space encircling the nucleus; for the first three shells, the capacity is $2$, $8$, and $8$ electrons respectively.

Ion

An electrically charged particle formed when an atom gains or loses electrons to become stable.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Ionic Bond

A strong chemical bond formed by the attraction between ions of opposite charges.

Covalent Bond

A strong chemical bond formed between atoms that share electrons.

Structural Formula

An illustration showing how atoms bond and are arranged, using single lines for single bonds and double lines for double bonds.

Nonpolar Covalent Bond

A bond in which electrons are shared equally between atoms with the same electronegativity.

Polar Covalent Bond

A bond in which electrons are not shared equally, resulting in an unequal charge distribution within the molecule.

Hydrogen Bond

A relatively weak attraction between the slightly positive hydrogen end of one polar molecule and the slightly negative end of another.

Reactants

The starting materials (atoms, ions, or molecules) in a chemical reaction.

Products

The substances formed at the conclusion of a chemical reaction.

Synthesis Reaction

A reaction where a more complex chemical structure is formed from simpler ones ($A + B \rightarrow AB$).

Decomposition Reaction

A reaction where chemical bonds are broken to form simpler structures ($AB \rightarrow A + B$).

Electrolytes

Substances that release ions in water, creating a solution capable of conducting an electric current.

Acids

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

Bases

Substances that release ions capable of combining with hydrogen ions.

Salts

Electrolytes formed when an acid reacts with a base.

pH Scale

A shorthand notation for hydrogen ion concentration ranging from $0$ to $14$, where $7$ is neutral.

Acidemia

A condition occurring when blood pH drops into the $7.0$ to $7.3$ range.

Alkalemia

A condition occurring when blood pH rises into the $7.5$ to $7.8$ range.

Buffers

Chemicals that resist changes in pH by binding or releasing hydrogen ions.

Organic Molecules

Molecules containing carbon ($C$) and hydrogen ($H$), such as carbohydrates, lipids, proteins, and nucleic acids.

Water

The most abundant compound in living material, making up two-thirds of the weight of an adult human.

Monosaccharides

Single sugars, such as glucose and fructose, which serve as the building blocks for larger carbohydrates.

Triglycerides

The most abundant lipids in the body, used for cellular energy and composed of one glycerol and three fatty acids.

Saturated Fatty Acid

A fatty acid containing only single carbon-carbon bonds, typically solid at room temperature.

Unsaturated Fatty Acid

A fatty acid containing one or more carbon-carbon double bonds, typically liquid at room temperature.

Phospholipids

Structural components of cell membranes consisting of glycerol, two fatty acids, and a phosphate group.

Steroids

Lipids characterized by four connected rings of carbon, with cholesterol being the primary example in the body.

Amino Acids

The building blocks of proteins, each containing an amino group, a carboxyl group, and a unique R group.

Peptide Bond

A bond formed between the amino group of one amino acid and the carboxyl group of an adjacent amino acid.

Primary Structure

The first level of protein structure, referring to the specific sequence of amino acids.

Tertiary Structure

The unique three-dimensional folding of a protein that determines its specific function.

Denaturation

The irreversible or reversible change in a protein's secondary and tertiary structure caused by heat, radiation, or pH changes.

Nucleotides

The building blocks of nucleic acids, consisting of a sugar, a phosphate group, and an organic base.

DNA

Deoxyribonucleic acid; a double chain of nucleotides that stores the genetic code and contains deoxyribose sugar.

RNA

Ribonucleic acid; a single chain of nucleotides containing ribose sugar that aids in protein synthesis.

CT Imaging

Computerized Tomography; an imaging technique using X-rays to create 3D images of soft tissues.

PET Imaging

Positron Emission Tomography; uses radioactive isotopes to detect biochemical activity and brain disorders.