Chapter 2: Chemical Basis of Life Vocabulary

Vocabulary flashcards covering chemical principles, elements, bonding, chemical reactions, pH balance, and organic and inorganic cellular constituents from Chapter 2.

Chemistry

The study of the composition of substances and how they change during chemical reactions.

Biochemistry

Biological chemistry that studies physiological processes and disease.

Matter

Anything that takes up space and has mass.

Mass

The amount of matter present.

Weight

The heaviness caused by gravitational pull on mass.

Element

The simplest type of matter with specific chemical properties.

Compound

A chemical combination of different elements.

Atom

The smallest particle of an element that still has the properties of that element.

Bulk Elements

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

Trace Elements

Elements needed by the body in small amounts, making up less than $0.1\%$ of body weight (e.g., Fe, I, Co, Cu, F, Mn, Zn).

Ultratrace Elements

Elements needed by the body in extremely tiny amounts, such as arsenic (As).

Proton

A relatively large subatomic particle with a positive electrical charge found in the nucleus.

Neutron

A relatively large subatomic particle with no electrical charge found in the nucleus.

Electron

An extremely small subatomic particle with a negative electrical charge and very little mass that moves around the nucleus.

Atomic Number

The unique number of protons in the nucleus of an atom.

Mass Number

The total number of protons plus neutrons in an atom's nucleus.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons and different mass numbers.

Ionizing Radiation

Radiation with enough energy to remove electrons from atoms, creating energy-charged ions and potentially damaging nearby atoms (e.g., alpha, beta, gamma radiation, X-rays).

Molecule

A particle formed when two or more atoms chemically combine.

Molecular Formula

A formula that shows which elements are present and how many atoms of each element are present in a molecule.

Ion

An electrically charged atom that has gained or lost electrons.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic Bond

A strong chemical bond formed when oppositely charged ions attract each other.

Covalent Bond

A strong chemical bond formed when atoms share electrons.

Nonpolar Covalent Bond

A covalent bond in which electrons are shared equally because the atoms have the same electronegativity.

Polar Covalent Bond

A covalent bond in which electrons are not shared equally because the atoms have different electronegativities, creating an unequal charge distribution.

Electronegativity

The ability of an atom to attract shared electrons toward its nucleus.

Hydrogen Bond

A relatively weak attraction between a slightly positive hydrogen atom and a slightly negative nitrogen or oxygen atom.

Reactants

Starting materials in a chemical reaction.

Products

Substances formed at the end of a chemical reaction.

Synthesis Reaction

A chemical reaction that forms a more complex chemical structure from simpler reactants.

Decomposition Reaction

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

Exchange Reaction

A chemical reaction where bonds are broken and new bonds are formed, exchanging parts between reactants.

Reversible Reaction

A chemical reaction where the products can change back into the original reactants.

Electrolytes

Substances that release ions in water and produce solutions that conduct electrical currents.

Acids

Electrolytes that release hydrogen ions ($\text{H}^+$) in water.

Bases

Substances that release ions capable of combining with hydrogen ions.

Salts

Electrolytes formed from the reaction between an acid and a base.

pH Scale

A scale running from $0$ to $14$ that indicates the concentration of hydrogen ions ($\text{H}^+$) in a solution.

Acidemia

A state in which blood pH drops to approximately $7.0$–$7.3$, causing potential fatigue and disorientation.

Alkalemia

A state in which blood pH rises to approximately $7.5$–$7.8$, causing potential dizziness and agitation.

Buffers

Chemicals that resist changes in pH by binding and releasing hydrogen ions ($\text{H}^+$).

Organic Molecules

Molecules that generally contain carbon and hydrogen, may dissolve in water or organic liquids, and do not release ions when water-soluble.

Inorganic Molecules

Molecules that generally do not contain both carbon and hydrogen, usually dissolve in water, and frequently dissociate into ions to act as electrolytes.

Monosaccharides

Single sugar carbohydrates, such as glucose and fructose.

Disaccharides

Double sugar carbohydrates, such as sucrose and lactose.

Polysaccharides

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

Triglycerides

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

Saturated Fatty Acid

A fatty acid with only single carbon-carbon bonds, typically solid at room temperature and originating from animals.

Unsaturated Fatty Acid

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

Phospholipid

A lipid composed of one glycerol, two fatty acids, and one phosphate group, featuring a water-soluble head and water-insoluble tails; forms the main structural component of cell membranes.

Steroids

Lipids characterized by four connected carbon rings, used as components of cell membranes and precursors for adrenal and sex hormones.

Primary Structure

The specific amino acid sequence of a protein.

Secondary Structure

The pleated or twisted arrangement of a protein formed by hydrogen bonding between nonadjacent amino acids.

Tertiary Structure

The unique 3-dimensional folded shape of a protein that determines its specific function.

Quaternary Structure

The protein structure level formed when two or more polypeptide chains connect together.

Denaturation

A change in the secondary and tertiary structure of a protein caused by heat, radiation, pH changes, or chemicals.

Nucleotide

The building block of nucleic acids, composed of a sugar, a phosphate group, and an organic base.

DNA (Deoxyribonucleic Acid)

A double-stranded double helix nucleic acid containing deoxyribose sugar and bases adenine, thymine, cytosine, and guanine, which stores genetic code.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid containing ribose sugar and bases adenine, uracil, cytosine, and guanine, which interacts with DNA to conduct protein synthesis.

Computerized Tomography (CT)

A medical imaging technique utilizing an X-ray-emitting device to produce 3-dimensional images of internal anatomy and soft tissue.

Positron Emission Tomography (PET)

A medical imaging technique utilizing positron-emitting radioactive isotopes to detect biochemical activity and evaluate blood flow.