Chapter 2: The Chemistry of Life (Video Notes) – VOCABULARY Flashcards

A comprehensive set of vocabulary flashcards covering the key terms and concepts from the lecture notes on matter, atoms, chemical bonds, reactions, inorganic compounds, water, acids/bases/salts, organic compounds, carbohydrates, lipids, proteins, nucleotides/nucleic acids, and basic biochemical principles.

Atom

The smallest unit of matter that retains the original properties of an element.

Subatomic particles

The particles that compose an atom: protons, neutrons, and electrons.

Proton

Positively charged subatomic particle located in the atomic nucleus.

Neutron

Electrically neutral subatomic particle located in the atomic nucleus.

Electron

Negatively charged subatomic particle outside the nucleus in electron shells.

Nucleus

The central core of the atom containing protons and neutrons.

Electron shells

Regions surrounding the nucleus that hold electrons; each shell holds a specific number.

First shell

The electron shell closest to the nucleus; holds 2 electrons.

Second shell

Electron shell that typically holds 8 electrons.

Third shell

Electron shell that can hold up to 18 electrons; often filled with 8 in many atoms.

Atomic number

Number of protons in the nucleus; defines the element.

Element

A substance that cannot be broken down into simpler substances by chemical means.

Periodic table

Organization of elements by increasing atomic number and properties.

Group (periodic table)

Columns in the periodic table; elements with similar properties.

Chemical symbol

A one- or two-letter abbreviation that represents an element.

Hydrogen

One of the four major elements in the human body.

Oxygen

One of the four major elements in the human body.

Carbon

One of the four major elements in the human body.

Nitrogen

One of the four major elements in the human body.

Mineral elements

Elements required in small amounts by the body; example: calcium.

Trace elements

Elements required in very small amounts for normal body function.

Mass number

Sum of protons and neutrons in the atomic nucleus.

Isotope

Atom with the same number of protons but different mass number due to varying neutrons.

Radioisotope

Unstable isotope that releases energy or radiation as it decays.

Ions

Atoms that carry a net electric charge due to unequal numbers of protons and electrons.

Cation

Positively charged ion formed when a metal atom loses electrons.

Anion

Negatively charged ion formed when a nonmetal gains electrons.

Ionic bond

Bond formed by electrical attraction between oppositely charged ions.

Covalent bond

Strong bond formed when atoms share one, two, or three electron pairs.

Molecule

Two or more atoms bonded together by covalent bonds.

Compound

Substance formed when two or more different elements bond.

Valence electrons

Outermost electrons involved in bonding.

Octet rule

Atoms are most stable when their valence shell has 8 electrons.

Duet rule

Atoms with 5 or fewer electrons are most stable with 2 electrons in the valence shell.

Electronegativity

Ability of an atom to attract shared electrons in a bond.

Fluorine (F)

Most electronegative element.

Polar covalent bond

A covalent bond where electrons are shared unequally, creating partial charges.

Nonpolar covalent bond

Covalent bond where electrons are shared equally, often between identical atoms.

Hydrogen bond

Weak attraction between a partially positive H and a partially negative atom; key to water properties.

Water as solvent

Water is the universal solvent due to its polarity and ability to surround solutes.

Hydrophilic

Solutes that readily dissolve in water (water-loving).

Hydrophobic

Solutes that do not dissolve in water (water-fearing).

Solute

Substance dissolved in a solvent.

Solvent

Substance that dissolves the solute.

Suspension

Mixture with large, unevenly distributed particles that settle out.

Colloid

Mixture with small, evenly distributed particles that do not settle out.

Solution

Homogeneous mixture with very small particles that do not settle.

Acid

Hydrogen ion donor; increases hydrogen ion concentration in solution.

Base

Hydrogen ion acceptor; decreases hydrogen ion concentration in solution.

pH scale

Scale from 0 to 14 showing hydrogen ion concentration.

Neutral

pH of 7; equal numbers of hydrogen and base ions.

Buffer

Chemical system that resists changes in pH.

Carbonic acid-bicarbonate buffer

Major buffer system in body fluids.

Salt

Ionic compound formed from a metal cation and nonmetal anion.

Electrolyte

Dissolved salt that conducts electricity in solution.

Dehydration synthesis

Bond-forming reaction where water is removed as monomers join.

Hydrolysis

Catabolic reaction using water to break polymers into subunits.

Monomer

A single subunit that can join with others to form polymers.

Polymer

A large molecule built from many monomer subunits.

Carbohydrate

Organic molecules that primarily serve as fuel; contain C, H, and O.

Monosaccharide

Simple sugar; basic unit of carbohydrates.

Glucose

A common monosaccharide and main cellular fuel.

Fructose

A simple sugar (monosaccharide) found in fruits.

Galactose

A monosaccharide; component of lactose.

Ribose

Five-carbon sugar found in RNA.

Deoxyribose

Five-carbon sugar found in DNA (lacks one oxygen).

Disaccharide

Two monosaccharides joined by dehydration synthesis.

Lactose

Disaccharide composed of glucose and galactose.

Sucrose

Disaccharide common table sugar; glucose + fructose.

Maltose

Disaccharide composed of two glucose units.

Polysaccharide

Many monosaccharides linked; used for energy storage or structure.

Glycogen

Storage polysaccharide in liver and skeletal muscle.

Lipid

Nonpolar, hydrophobic molecules rich in carbon and hydrogen.

Fatty acid

Lipid monomer with a hydrocarbon chain; may be saturated or unsaturated.

Saturated fatty acid

No double bonds; typically solid at room temperature.

Monounsaturated fatty acid

One double bond in the hydrocarbon chain; usually liquid.

Polyunsaturated fatty acid

Two or more double bonds in the carbon chain; usually liquid.

Triglyceride

Three fatty acids linked to glycerol; major energy storage fat.

Glycerol

Three-carbon backbone of triglycerides.

Phospholipid

Lipid with two fatty acids and a phosphate group; amphiphilic.

Amphiphilic

Molecule with both polar (head) and nonpolar (tail) regions.

Cholesterol

Steroid lipid; backbone for steroid hormones and membrane structure.

Steroid

Lipid with a four-ring hydrocarbon structure.

Proteins

Macromolecules made of amino acids; perform many cellular functions.

Amino acids

Monomers that join to form proteins.

Peptide bond

Bond linking amino acids in a protein chain.

Primary structure

Amino acid sequence of a polypeptide.

Secondary structure

Folding patterns like alpha helices and beta-pleated sheets.

Alpha helix

Coiled, spring-like secondary structure of proteins.

Beta-pleated sheet

Folded sheet-like secondary structure in proteins.

Tertiary structure

Three-dimensional shape of a single polypeptide.

Quaternary structure

Arrangement of two or more polypeptide chains in a protein.

Protein denaturation

Loss of protein shape due to heat, pH changes, or chemicals.

Nucleotides

Monomers of nucleic acids consisting of a base, sugar, and phosphate.

Nitrogenous base

Part of a nucleotide; includes purines and pyrimidines.

Purines

Double-ringed bases (adenine; guanine).

Pyrimidines

Single-ringed bases (cytosine; uracil in RNA; thymine in DNA).

Adenine

Purine base that pairs with thymine in DNA and with uracil in RNA.

Guanine

Purine base that pairs with cytosine.

Cytosine

Pyrimidine base that pairs with guanine.