Cellular Level

Matter

Anything that occupies space and has mass, composed of elements.

Atom

The building block of all matter.

Element

A pure substance composed of atoms; 96% of the body consists of Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N).

Nucleus

The core of an atom, containing protons and neutrons.

Electron Cloud

The region surrounding the nucleus of an atom, where electrons are found.

Atomic Number

The number of protons in an atom, which identifies the element.

Mass Number

The total number of protons and neutrons in an atom.

Isotope

Atoms of the same element that have different numbers of neutrons.

Valence Electrons

Electrons in the outermost shell involved in chemical bonding.

Octet Rule

Atoms tend to bond to achieve 8 valence electrons.

Molecule

Two or more atoms chemically bonded together.

Compound

A molecule composed of different elements.

Ionic Bonds

Bonds involving the transfer of electrons, forming charged ions.

Cation

An ion that has lost electrons and is positively charged.

Anion

An ion that has gained electrons and is negatively charged.

Covalent Bonds

Bonds that involve the sharing of electrons.

Non-Polar Covalent Bond

A bond where electrons are shared equally.

Polar Covalent Bond

A bond where electrons are shared unequally.

Hydrogen Bonds

Weak attractions between polar molecules.

Synthesis

A type of reaction where molecules combine to form a larger molecule.

Decomposition

A reaction where large molecules are broken down into smaller ones.

Oxidation-Reduction (Redox)

A type of reaction where oxidation is the loss of electrons and reduction is the gain of electrons.

Temperature

One of the factors that affect reaction rates.

Water

A universal solvent with high heat capacity, involved in hydrolysis and dehydration synthesis.

Salts

Dissociate into electrolytes (ions); important for nerve impulses and muscle contractions.

pH Scale

A measure of acidity or basicity based on H⁺ concentration.

Acidosis

A condition with low pH where bicarbonate binds with H⁺ to reduce concentration.

Alkalosis

A condition with high pH where carbonic acid dissociates to increase H⁺ concentration.

Carbohydrates

Organic molecules that provide quick energy and some cell structure.

Monosaccharides

The monomers of carbohydrates, also known as simple sugars.

Disaccharides

Molecules composed of two linked monosaccharides.

Polysaccharides

Long chains of monosaccharides (e.g., glycogen, starch).

Lipids

Organic molecules that include triglycerides, phospholipids, steroids, and eicosanoids.

Triglycerides

Lipids used for energy storage.

Proteins

Macromolecules that serve as enzymes, structural components, and for transport.

Amino Acids

The monomers of proteins, consisting of an acid group, amine group, and R group.

Nucleic Acids

Polymers made of nucleotides; include DNA and RNA.

ATP (Adenosine Triphosphate)

The energy currency of the cell, composed of adenine, ribose, and three phosphate groups.