Bio 2.1-2.3 flashcards

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Atom

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

Nucleus

The center of an atom, containing protons and neutrons.

Electron

A subatomic particle with a negative charge that orbits the nucleus.

Proton

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

Neutron

A subatomic particle with no charge (neutral) found in the nucleus.

Element

A pure substance that consists of only one type of atom.

Molecule

Two or more atoms bonded together.

Compound

A substance made of two or more different elements chemically combined.

Covalent bond

A chemical bond where electrons are shared between atoms.

Ionic bond

A chemical bond where one or more electrons are transferred from one atom to another.

Cohesion

The attraction between molecules of the same substance (e.g., water molecules sticking together).

Ion

An atom or molecule that has gained or lost electrons and has a charge.

Adhesion

The attraction between molecules of different substances (e.g., water sticking to plant cells).

Polar

A molecule with uneven distribution of charge, having a positive and negative end.

Solution

A homogeneous mixture of two or more substances.

Solute

The substance that is dissolved in a solution.

Solvent

The substance that does the dissolving in a solution.

Suspension

A mixture in which particles are dispersed throughout but not dissolved; particles may settle over time.

pH

A scale from 0–14 that measures how acidic or basic a solution is (7 is neutral, below 7 is acidic, above 7 is basic).

Acid

A substance that increases the concentration of hydrogen ions (H⁺) in a solution; pH below 7.

Base

A substance that decreases the concentration of hydrogen ions (H⁺) in a solution; pH above 7.

Buffer

A substance that resists changes in pH by accepting or donating hydrogen ions.

Monomer

A small molecule that can join with other molecules to form a polymer.

Polymer

A large molecule made up of repeating monomers.

Carbohydrate

An organic compound made of carbon, hydrogen, and oxygen; main source of energy.

Monosaccharide

A single sugar molecule (e.g., glucose).

Polysaccharide

A large molecule made of many monosaccharides (e.g., starch, cellulose).

Lipid

Organic compounds made mostly of carbon and hydrogen; store energy and make up cell membranes (e.g., fats, oils, waxes).

Nucleic acid

Macromolecules that store and transmit genetic information (DNA and RNA).

Nucleotide

The building block of nucleic acids, made of a sugar, phosphate, and nitrogenous base.

Protein

Macromolecules made of amino acids; perform a wide range of functions in the body.

Amino acid

The building block of proteins; contains an amino group, carboxyl group, and side chain (R group).